Full alphabetical reference · 480 meanings
4D — Four-dimensional construction modeling
BIM & digital coordination · Acronym or initialism · Industry-wide — A model use that links three-dimensional project information with schedule or time information.
In practice: The team uses a 4D sequence to review crane access by phase.
4D is a model-use label, not a guarantee of schedule accuracy.
GSA ↗
5D — Five-dimensional construction modeling
BIM & digital coordination · Acronym or initialism · Industry-wide — A common model-use label connecting modeled quantities and project information with cost information.
In practice: The estimator links model quantities to cost data for a 5D review.
The meaning and integration scope should be defined in the BEP.
GSA ↗
A/E — Architect-engineer
Project team & organizations · Acronym or initialism · Industry-wide — A collective reference to architectural and engineering professionals or their services.
In practice: The agency selects an A/E firm for design services.
Often written AE in procurement documents.
Acquisition.gov ↗
AAC — Autoclaved aerated concrete
Concrete & masonry · Acronym or initialism · Industry-wide — A lightweight cellular concrete product cured under heat and pressure.
In practice: The enclosure design uses AAC wall panels.
American Concrete Institute ↗
AADT — Annual average daily traffic
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Traffic volume averaged across all days of a year at a specified location.
In practice: The engineer uses AADT with vehicle classification data.
FHWA ↗
AASHTO — American Association of State Highway and Transportation Officials
Project team & organizations · Organization · U.S. specific — An organization representing state transportation departments and publishing transportation standards and technical guidance.
In practice: The bridge specification identifies an AASHTO document and edition.
Use the edition incorporated into the project's governing requirements.
FHWA ↗
AB — Air barrier
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A connected system of materials intended to control air leakage through the enclosure.
In practice: The enclosure review checks AB continuity at the roof-wall joint.
AB may mean anchor bolt in structural notes.
ASHRAE ↗
AB — Anchor bolt
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A bolt used to connect a component to concrete, masonry, or another supporting material.
In practice: The base plate detail locates each AB.
The specification may use anchor rod; verify type, embedment, and design requirements.
AISC ↗
ABA — Architectural Barriers Act
Codes & accessibility · Code, standard or program · U.S. specific — A U.S. law addressing accessibility of specified federally funded facilities.
In practice: The federal project identifies the applicable ABA accessibility standards.
U.S. Access Board ↗
ABC — Associated Builders and Contractors
Project team & organizations · Organization · U.S. specific — A U.S. construction trade association associated with merit shop construction.
In practice: The contractor checks ABC workforce development resources.
Associated Builders and Contractors ↗
AC — Alternating current
Electrical & fire protection · Acronym or initialism · Industry-wide — Electric current that periodically reverses direction.
In practice: The motor nameplate identifies its AC supply requirements.
AC on a mechanical drawing can mean air conditioning.
OSHA ↗
AC — Air conditioning
Electrical & fire protection · Acronym or initialism · Industry-wide — The process or equipment used to control indoor air conditions, commonly cooling and dehumidification.
In practice: The mechanical schedule lists the AC equipment serving the room.
ASHRAE ↗
AC — Actual cost
Estimating & project controls · Acronym or initialism · Industry-wide — The cost incurred for the work performed within the defined accounting scope.
In practice: The cost report compares AC with EV.
AC also means alternating current or air conditioning.
U.S. Department of Energy ↗
ACH — Air changes per hour
Mechanical & HVAC · Acronym or initialism · Industry-wide — The airflow through a space expressed as multiples of its volume per hour.
In practice: The engineer calculates ACH from the specified airflow and room volume.
Identify whether the value refers to total, outdoor, or equivalent clean airflow.
ASHRAE ↗
ACI — American Concrete Institute
Project team & organizations · Organization · U.S. specific — An organization developing concrete knowledge, standards, and certification programs.
In practice: The specification identifies an ACI standard and edition.
American Concrete Institute ↗
ACT — Acoustical ceiling tile
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A ceiling panel product used as part of an acoustical ceiling system.
In practice: The RCP shows a suspended ACT grid.
Some schedules use ACT for acoustical ceiling treatment; check the legend.
U.S. Department of Veterans Affairs ↗
ADA — Americans with Disabilities Act
Codes & accessibility · Code, standard or program · U.S. specific — A U.S. civil rights law that includes accessibility requirements affecting covered facilities.
In practice: The designer reviews ADA requirements alongside the building code.
Code compliance and ADA compliance are related but distinct inquiries.
U.S. Access Board ↗
ADAAG — Americans with Disabilities Act Accessibility Guidelines
Codes & accessibility · Code, standard or program · U.S. specific — Accessibility guidelines that form part of the background to applicable federal accessibility standards.
In practice: An older specification references ADAAG terminology.
Use the applicable enforceable standards for the facility and project.
U.S. Access Board ↗
AED — Automated external defibrillator
Safety & occupational health · Acronym or initialism · Industry-wide — A device that analyzes heart rhythm and can deliver a shock when indicated.
In practice: The emergency plan identifies the AED location.
OSHA ↗
AFCI — Arc-fault circuit interrupter
Electrical & fire protection · Acronym or initialism · Industry-wide — A protective device intended to detect specified hazardous arcing conditions and interrupt the circuit.
In practice: The dwelling circuit schedule identifies AFCI protection.
AFCI and GFCI address different hazards.
OSHA ↗
AFF — Above finished floor
Drawings & specifications · Drawing abbreviation · Industry-wide — A vertical dimension measured upward from the completed floor surface.
In practice: A device mounting note calls for 48 inches AFF.
Check which finished floor level applies; it is not automatically the structural slab elevation.
U.S. Department of Veterans Affairs ↗
AFG — Above finished grade
Drawings & specifications · Drawing abbreviation · Industry-wide — A height measured from the completed exterior ground level.
In practice: The outlet mounting height is specified AFG.
U.S. Department of Veterans Affairs ↗
AGC — Associated General Contractors of America
Project team & organizations · Organization · U.S. specific — A U.S. construction trade association representing general contractors and related firms.
In practice: The company uses AGC training resources for project staff.
AGC of America ↗
AHA — Activity hazard analysis
Safety & occupational health · Acronym or initialism · Industry-wide — A documented analysis of hazards and controls for an activity, commonly used on USACE projects.
In practice: The team prepares an AHA for the planned excavation activity.
Use the contract's required process and acceptance requirements.
USACE ↗
AHJ — Authority having jurisdiction
Project team & organizations · Organization · U.S. specific — The organization, office, or individual empowered to administer or enforce applicable requirements.
In practice: The team confirms the inspection sequence with the AHJ.
More than one AHJ may be involved in a project.
NFPA ↗
AHU — Air-handling unit
Mechanical & HVAC · Acronym or initialism · Industry-wide — Equipment that moves and conditions air using components such as fans, filters, and coils.
In practice: The AHU schedule lists airflow and coil capacities.
A unit may perform several functions; check its schedule.
ASHRAE ↗
AIA — American Institute of Architects
Project team & organizations · Organization · U.S. specific — A professional organization for architects in the United States.
In practice: The specification cites an AIA contract document by number and edition.
AIA Contract Documents ↗
AIC — Ampere interrupting capacity
Electrical & fire protection · Acronym or initialism · Industry-wide — Common industry shorthand for a protective device's interrupting rating under specified conditions.
In practice: The panel submittal lists the circuit breaker's AIC rating.
Use the manufacturer's actual interrupting rating and voltage basis.
OSHA ↗
AISC — American Institute of Steel Construction
Project team & organizations · Organization · U.S. specific — An organization developing structural steel standards and technical resources.
In practice: The structural notes reference an AISC specification.
AISC ↗
ALT — Alternate
Drawings & specifications · Drawing abbreviation · Industry-wide — An identified alternative scope, material, or bid item for consideration.
In practice: The bid form asks for an ALT price for a different roof system.
Alternates require explicit acceptance according to the procurement documents.
U.S. Department of Veterans Affairs ↗
ANSI — American National Standards Institute
Project team & organizations · Organization · U.S. specific — An organization coordinating the U.S. voluntary standards and conformity-assessment system.
In practice: The equipment specification calls for a named ANSI-approved standard.
ASHRAE ↗
AOR — Architect of record
Project team & organizations · Acronym or initialism · Industry-wide — The architect responsible for architectural documents and services within the assigned scope.
In practice: The AOR coordinates the permit drawing revision.
Role allocation can differ on projects with separate design and record architects.
AIA Contract Documents ↗
APA — APA – The Engineered Wood Association
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An industry organization providing engineered wood product certification and technical guidance.
In practice: The inspector checks the APA panel mark.
APA is the organization's current name, not a direction to expand an obsolete name.
APA – The Engineered Wood Association ↗
APF — Assigned protection factor
Safety & occupational health · Acronym or initialism · Industry-wide — The expected level of respiratory protection from a properly functioning respirator class used within an effective program.
In practice: The respiratory program uses the applicable APF when selecting equipment.
APF is not a guarantee for an improperly fitted or used respirator.
OSHA ↗
APP — Atactic polypropylene
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A polymer used to modify bitumen in some roofing membranes.
In practice: The roof replacement specification calls for an APP-modified system.
NRCA ↗
ASD — Allowable strength design
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An AISC design method comparing required strength with nominal strength divided by a safety factor.
In practice: The steel calculation identifies ASD load combinations and capacities.
Older and other-discipline documents may use ASD for allowable stress design.
AISC ↗
ASD — Allowable stress design
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A design approach checking calculated stresses against allowable values.
In practice: An older design report labels its method ASD.
In current AISC terminology, ASD means allowable strength design.
AISC ↗
ASHRAE — American Society of Heating, Refrigerating and Air-Conditioning Engineers
Project team & organizations · Organization · U.S. specific — A professional society developing building-services technical guidance and standards, branded ASHRAE.
In practice: The mechanical design criteria identify an ASHRAE standard.
ASHRAE ↗
ASI — Architect's supplemental instructions
Project delivery & contracts · Acronym or initialism · Industry-wide — Written clarification or instruction from the architect, commonly used for minor changes without changing contract sum or time.
In practice: An ASI clarifies a finish transition detail.
If an instruction affects cost or time, use the applicable change procedure.
AIA Contract Documents ↗
ASTM — ASTM International
Project team & organizations · Organization · U.S. specific — A standards organization publishing test methods and material specifications used in construction.
In practice: The concrete specification cites the applicable ASTM test method.
The current organization name is ASTM International; the older expanded name remains common in legacy documents.
American Concrete Institute ↗
ATS — Automatic transfer switch
Electrical & fire protection · Acronym or initialism · Industry-wide — A device that transfers a load between power sources under defined automatic controls.
In practice: The standby system uses an ATS to transfer selected loads.
ASHRAE ↗
AWG — American wire gauge
Electrical & fire protection · Acronym or initialism · Industry-wide — A sizing system for electrical conductors.
In practice: The conductor schedule lists the required AWG size.
ASHRAE ↗
AWP — Aerial work platform
Safety & occupational health · Acronym or initialism · Industry-wide — A commonly used term for elevated work platforms, often appearing in older equipment terminology.
In practice: The rental quote describes the unit as an AWP.
OSHA ↗
AWS — American Welding Society
Project team & organizations · Organization · U.S. specific — An organization producing welding standards, training, and certification programs.
In practice: The project identifies an AWS welding code in the specifications.
American Welding Society ↗
BAC — Budget at completion
Estimating & project controls · Acronym or initialism · Industry-wide — The total authorized budget for the defined earned-value scope.
In practice: The baseline sets BAC before reporting performance.
U.S. Department of Energy ↗
BACnet — Building Automation and Control Networks
Mechanical & HVAC · Acronym or initialism · Industry-wide — A communications protocol standard used for interoperable building automation data exchange.
In practice: The controls specification calls for BACnet communication.
Protocol support alone does not guarantee every required integration function.
ASHRAE ↗
BAS — Building automation system
Mechanical & HVAC · Acronym or initialism · Industry-wide — A system monitoring and controlling building equipment and operating sequences.
In practice: The BAS trends fan status and space temperatures.
ASHRAE ↗
BC — Bottom of curb
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation at the lower curb reference identified in the civil legend.
In practice: The grader compares BC and TOC elevations.
Some drawings use BC for back of curb or base cabinet; follow the project legend.
U.S. Department of Veterans Affairs ↗
BCF — BIM Collaboration Format
BIM & digital coordination · Acronym or initialism · Industry-wide — An open format for exchanging model-related issues and viewpoints among applications.
In practice: The coordinator sends clash comments as BCF issues.
buildingSMART International ↗
BCY — Bank cubic yard
Civil, survey & earthwork · Unit or symbol · Industry-wide — A cubic yard of material measured in its original, undisturbed ground condition.
In practice: The excavation estimate reports quantities in BCY.
Do not equate bank, loose, and compacted volumes without appropriate factors.
FHWA ↗
BEP — BIM execution plan
BIM & digital coordination · Acronym or initialism · Industry-wide — A plan defining model uses, responsibilities, exchanges, and coordination procedures.
In practice: The team agrees on the BEP before model development.
AIA documents may use BIM execution plan without the BEP acronym.
BIMForum ↗
BFP — Backflow preventer
Plumbing & utilities · Acronym or initialism · Industry-wide — A device or assembly intended to prevent reverse flow into a protected water supply.
In practice: The site detail identifies the BFP assembly.
Device selection depends on hazard classification and local requirements.
International Code Council ↗
BIM — Building information modeling
BIM & digital coordination · Acronym or initialism · Industry-wide — A process using coordinated digital information and models to support building delivery and operation.
In practice: The BIM team coordinates structural and MEP systems before installation.
The term can also refer to building information models; the delivery requirements define the actual scope.
GSA ↗
BM — Benchmark
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A survey reference point with an established elevation.
In practice: The surveyor ties layout elevations to the designated BM.
BM can mean beam in structural drawing legends.
NOAA / NGS ↗
BMP — Best management practice
Environment & sustainability · Acronym or initialism · Industry-wide — A structural measure or operating practice used to prevent or reduce pollution.
In practice: The erosion-control plan identifies a stabilized entrance as a BMP.
U.S. EPA ↗
BMS — Building management system
Mechanical & HVAC · Acronym or initialism · Industry-wide — A supervisory system used to manage building services, often overlapping with BAS terminology.
In practice: The owner reviews alarms through the BMS interface.
The project's naming convention and integration scope determine the distinction.
ASHRAE ↗
BO — Bottom of
Drawings & specifications · Drawing abbreviation · Industry-wide — An elevation or position prefix referring to the underside of a named element.
In practice: A section labels the BO beam elevation.
The object following BO is essential to interpretation.
U.S. Department of Veterans Affairs ↗
BOD — Basis of design
Design phases & commissioning · Acronym or initialism · Industry-wide — The design team's explanation of technical approaches and assumptions used to satisfy project requirements.
In practice: The engineer documents system selection in the BOD.
BOD is a design rationale; the OPR expresses what the owner needs.
WBDG / NIBS ↗
BOQ — Bill of quantities
Estimating & project controls · Acronym or initialism · Industry-wide — An itemized document listing measured work quantities for pricing or administration.
In practice: The bidder prices each item in the BOQ.
Usage varies; U.S. projects may use bid schedules or other quantity formats.
Acquisition.gov ↗
BOS — Bottom of steel
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation at the bottom surface of a structural steel member.
In practice: The coordinator compares BOS with the duct clearance.
AISC ↗
BTU — British thermal unit
Units & measurements · Unit or symbol · Industry-wide — A customary heat-energy unit used in U.S. mechanical work.
In practice: The energy report expresses a heat quantity in BTU.
Heating and cooling capacity requires an energy-per-time unit.
ASHRAE ↗
BTU/h — British thermal units per hour
Units & measurements · Unit or symbol · Industry-wide — A rate of heat transfer commonly used for heating or cooling capacity.
In practice: The heater schedule lists its output in BTU/h.
Do not omit the time basis when comparing capacity.
ASHRAE ↗
BUR — Built-up roofing
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A roof system assembled from multiple reinforcing plies and bituminous layers.
In practice: The roof survey identifies an existing BUR assembly.
System composition and repair compatibility vary.
NRCA ↗
C&D — Construction and demolition
Environment & sustainability · Acronym or initialism · Industry-wide — The construction and demolition activities or material stream described in a waste plan.
In practice: The waste log records C&D materials sent for recycling.
Diversion claims need a defined measurement and destination basis.
U.S. EPA ↗
CAD — Computer-aided design
BIM & digital coordination · Acronym or initialism · Industry-wide — Software-supported preparation of drawings or digital design geometry.
In practice: The consultant issues CAD drawings under the project standards.
A CAD drawing is not necessarily an information-rich BIM model.
GSA ↗
CAR — Corrective action request
Quality & inspection · Acronym or initialism · Industry-wide — A request to investigate and correct a nonconformance and, when required, address its cause.
In practice: The quality manager opens a CAR after a recurring defect.
Some systems expand CAR as corrective action report.
AISC ↗
CAV — Constant air volume
Mechanical & HVAC · Acronym or initialism · Industry-wide — An air-distribution approach designed to maintain a substantially constant airflow in its operating mode.
In practice: The mechanical plan labels a CAV system serving the room.
ASHRAE ↗
CBA — Collective bargaining agreement
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — An agreement between an employer and a labor organization governing specified employment terms.
In practice: The payroll setup reflects the applicable CBA classifications and benefits.
U.S. Department of Labor ↗
CBR — California bearing ratio
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A penetration-based index used to assess subgrade and aggregate support characteristics.
In practice: The pavement designer reviews soaked CBR results.
FHWA ↗
CCD — Construction change directive
Project delivery & contracts · Acronym or initialism · Industry-wide — A contract instrument directing a change before the parties have fully agreed on its cost or time effects.
In practice: A CCD directs revised work while the adjustment is evaluated.
Authority and pricing procedures depend on the contract.
AIA Contract Documents ↗
CCIP — Contractor-controlled insurance program
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A project insurance arrangement sponsored by a contractor for defined participants and coverage.
In practice: The trade contractor reviews the CCIP manual before enrollment.
The acronym does not specify every line of coverage.
AIA Contract Documents ↗
CCY — Compacted cubic yard
Civil, survey & earthwork · Unit or symbol · Industry-wide — A cubic yard of material measured after compaction to the defined condition.
In practice: The fill estimate states the required CCY in place.
FHWA ↗
CD — Construction documents
Design phases & commissioning · Acronym or initialism · Industry-wide — The drawings and specifications prepared to communicate requirements for construction and related approvals.
In practice: The team completes the CD package for the next issue.
Document status, completeness, and permitted use depend on the issue and contract.
AIA Contract Documents ↗
CDE — Common data environment
BIM & digital coordination · Acronym or initialism · Industry-wide — An agreed source and process for collecting, managing, and sharing project information.
In practice: The team controls document status and access through the CDE.
A shared folder alone does not define a complete information-management process.
buildingSMART International ↗
CDX — C-D plywood with exterior glue bond
Structural steel, wood & welding · Acronym or initialism · Industry-wide — Common trade shorthand for plywood with C and D veneer grades and a moisture-resistant glue bond.
In practice: The buyer checks the actual panel grade stamp against the CDX description.
CDX is shorthand, not a complete panel specification; Exposure 1 is not intended for permanent weather exposure.
APA – The Engineered Wood Association ↗
CFCI — Contractor furnished, contractor installed
Project delivery & contracts · Acronym or initialism · Industry-wide — A responsibility split assigning both supply and installation to the contractor.
In practice: The equipment matrix marks the exhaust fans CFCI.
U.S. Department of Veterans Affairs ↗
CFM — Cubic feet per minute
Mechanical & HVAC · Unit or symbol · Industry-wide — A U.S. customary volumetric airflow rate.
In practice: The balancing report lists 300 CFM at the diffuser.
Air density and rating conditions matter for some comparisons.
ASHRAE ↗
CFS — Cold-formed steel
Structural steel, wood & welding · Acronym or initialism · Industry-wide — Steel members shaped at relatively low temperatures, commonly from sheet or strip.
In practice: The partition design uses CFS studs.
Cold-formed steel design follows the applicable member and system standards.
AISC ↗
CGL — Commercial general liability
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A category of liability insurance addressing specified third-party claims subject to policy terms.
In practice: The subcontract requires CGL coverage with identified limits and endorsements.
AIA Contract Documents ↗
CGP — Construction general permit
Environment & sustainability · Acronym or initialism · Industry-wide — A general permit providing coverage for eligible construction stormwater discharges under stated conditions.
In practice: The operator checks the applicable CGP before submitting the NOI.
EPA and authorized states have different permits and coverage areas.
U.S. EPA ↗
CHW — Chilled water
Mechanical & HVAC · Acronym or initialism · Industry-wide — Water circulated to absorb heat in cooling coils or other cooling equipment.
In practice: The mechanical plan identifies CHW piping to the AHU.
ASHRAE ↗
CHWR — Chilled water return
Mechanical & HVAC · Acronym or initialism · Industry-wide — The chilled-water flow path returning water from the load toward the cooling source.
In practice: The coil detail identifies the CHWR connection.
ASHRAE ↗
CHWS — Chilled water supply
Mechanical & HVAC · Acronym or initialism · Industry-wide — The chilled-water pipe or flow path delivering cooled water to the load.
In practice: The installer traces CHWS from the plant to the coil.
ASHRAE ↗
CI — Continuous insulation
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — Insulation extending across structural members with limited interruptions as defined by the governing criteria.
In practice: The wall section shows exterior CI outside the sheathing.
CI in plumbing schedules can instead mean cast iron.
U.S. Department of Energy ↗
CI — Cast iron
Plumbing & utilities · Acronym or initialism · Industry-wide — An iron-based material commonly identified in drainage pipe schedules.
In practice: The plumbing specification calls for CI soil pipe.
CI means continuous insulation in enclosure discussions.
ASHRAE ↗
CIP — Cast-in-place
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete placed in its final location at the project rather than delivered as a finished precast element.
In practice: The drawings call for a CIP retaining wall.
Also written cast in situ in some international documents.
American Concrete Institute ↗
CJ — Control joint
Drawings & specifications · Drawing abbreviation · Industry-wide — A planned joint used to manage the location of cracking or movement.
In practice: The slab plan identifies CJ locations.
Some concrete documents use CJ for construction joint.
American Concrete Institute ↗
CJ — Construction joint
Drawings & specifications · Drawing abbreviation · Industry-wide — The interface between concrete placements made at different times.
In practice: The pour plan locates a CJ at the approved stopping point.
This is not automatically a contraction or control joint.
American Concrete Institute ↗
CJP — Complete joint penetration
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A groove weld condition with weld metal extending through the joint thickness as specified.
In practice: The connection detail calls for a CJP groove weld.
AISC ↗
CL — Centerline
Drawings & specifications · Drawing abbreviation · Industry-wide — A reference line through the middle of a feature used for layout or dimensioning.
In practice: The drawing dimensions the column CL from the grid.
The centerline symbol may appear instead of the letters.
U.S. Department of Veterans Affairs ↗
CLG — Ceiling
Drawings & specifications · Drawing abbreviation · Industry-wide — The overhead interior finish surface or ceiling system.
In practice: The room finish schedule lists the CLG material.
U.S. Department of Veterans Affairs ↗
CLT — Cross-laminated timber
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An engineered timber panel made from bonded layers with adjacent layers oriented across each other.
In practice: The floor assembly uses CLT panels.
Fire, acoustics, connections, and moisture protection require coordinated design.
APA – The Engineered Wood Association ↗
CM — Construction manager
Project team & organizations · Acronym or initialism · Industry-wide — A person or firm managing construction planning, coordination, cost, or delivery under a defined role.
In practice: The CM leads a coordination meeting with the owner.
A construction manager may act as adviser or hold construction risk.
AIA Contract Documents ↗
CM/GC — Construction manager/general contractor
Project delivery & contracts · Acronym or initialism · Industry-wide — A delivery method involving early contractor participation followed by negotiated construction work under program rules.
In practice: The highway agency uses CM/GC to plan staging before construction.
Public program details differ by agency.
FHWA ↗
CMAR — Construction manager at risk
Project delivery & contracts · Acronym or initialism · Industry-wide — A delivery approach where a construction manager provides preconstruction input and later assumes contractual construction responsibility.
In practice: The CMAR team helps develop trade packages before construction.
Also written CM at risk or CM/GC in some public programs.
AIA Contract Documents ↗
CMMS — Computerized maintenance management system
Design phases & commissioning · Acronym or initialism · Industry-wide — Software used to manage assets, maintenance work orders, and related records.
In practice: The facilities team imports asset data into the CMMS.
WBDG / NIBS ↗
CMP — Corrugated metal pipe
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Metal drainage pipe formed with corrugations for stiffness.
In practice: The culvert schedule identifies an existing CMP.
FHWA ↗
CMU — Concrete masonry unit
Concrete & masonry · Acronym or initialism · Industry-wide — A manufactured concrete block used in masonry construction.
In practice: The wall schedule specifies reinforced CMU.
Unit dimensions, strength, grout, and reinforcement follow the specification.
American Concrete Institute ↗
CO — Change order
Project delivery & contracts · Acronym or initialism · Industry-wide — A formal change to the construction contract that records agreed changes to work, price, or time.
In practice: The owner approves a CO for an added entrance canopy.
Confirm approvals required by the actual contract; CO has other construction meanings.
AIA Contract Documents ↗
CO — Cleanout
Plumbing & utilities · Acronym or initialism · Industry-wide — An accessible fitting or opening allowing cleaning and inspection of drainage piping.
In practice: The floor plan locates a CO at the base of the stack.
The same letters also refer to contract changes and occupancy documents.
ASHRAE ↗
CO — Certificate of occupancy
Codes & accessibility · Code, standard or program · U.S. specific — An official document authorizing occupancy or use under the issuing jurisdiction's process.
In practice: The owner coordinates final inspections before requesting the CO.
It is distinct from a contract change order and does not resolve every contractual closeout obligation.
International Code Council ↗
CO — Carbon monoxide
Safety & occupational health · Chemical symbol · Industry-wide — A toxic, colorless, odorless gas produced by incomplete combustion and other processes.
In practice: The safety plan addresses CO from fuel-powered equipment in enclosed areas.
This chemical symbol is unrelated to change orders or occupancy certificates.
NIOSH / CDC ↗
COBie — Construction-Operations Building information exchange
BIM & digital coordination · Acronym or initialism · Industry-wide — A structured information exchange for handing over asset data for operation and maintenance.
In practice: The owner requests COBie equipment data at handover.
The required fields and delivery format belong in the project requirements.
GSA ↗
COI — Certificate of insurance
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A document summarizing information about insurance policies identified on it.
In practice: The owner requests a COI before site mobilization.
A certificate is not the policy and does not itself expand coverage.
AIA Contract Documents ↗
COR — Change order request
Project delivery & contracts · Acronym or initialism · Industry-wide — A request asking for a change to contract scope, compensation, or schedule.
In practice: The subcontractor submits a COR with labor and material backup.
A request is not the same as an approved change.
AIA Contract Documents ↗
CPI — Cost performance index
Estimating & project controls · Acronym or initialism · Industry-wide — An earned-value ratio calculated as earned value divided by actual cost.
In practice: A CPI below 1 indicates more cost than earned value on that reporting basis.
The ratio is undefined when actual cost is zero; it is not a profit margin.
U.S. Department of Energy ↗
CPM — Critical path method
Estimating & project controls · Acronym or initialism · Industry-wide — A scheduling method using activity logic and durations to calculate timing and paths controlling completion.
In practice: The scheduler updates the CPM model after progress review.
The critical path can change as progress and logic change.
FHWA ↗
CPR — Cardiopulmonary resuscitation
Safety & occupational health · Acronym or initialism · Industry-wide — Emergency measures used to support circulation and breathing in cardiac arrest.
In practice: The site identifies trained CPR responders and emergency contacts.
A definition does not substitute for recognized training.
OSHA ↗
CPR — Certified payroll report
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A payroll submission accompanied by the required certification under the applicable prevailing wage program.
In practice: The payroll team reconciles time records before submitting the CPR.
CPR in a safety context means cardiopulmonary resuscitation.
U.S. Department of Labor ↗
CPT — Cone penetration test
Civil, survey & earthwork · Acronym or initialism · Industry-wide — An in-situ test measuring resistance as an instrumented cone is pushed into soil.
In practice: The geotechnical team uses CPT data to characterize subsurface layers.
FHWA ↗
CPVC — Chlorinated polyvinyl chloride
Plumbing & utilities · Acronym or initialism · Industry-wide — A chlorinated thermoplastic used in specified piping systems.
In practice: The submittal identifies CPVC pipe and compatible fittings.
Temperature, pressure, listing, and chemical compatibility depend on the system.
ASHRAE ↗
CQC — Contractor quality control
Quality & inspection · Acronym or initialism · Industry-wide — The contractor's program for controlling the quality of its work under the contract.
In practice: The CQC manager documents required inspections and corrections.
USACE and other agencies may prescribe specific CQC processes.
Acquisition.gov ↗
CSI — Construction Specifications Institute
Project team & organizations · Organization · U.S. specific — A professional organization associated with construction specifications and information standards.
In practice: The project manual organizes work using CSI-related classification conventions.
Construction Specifications Institute ↗
CWHSSA — Contract Work Hours and Safety Standards Act
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A federal law addressing work hours, overtime, and safety on certain covered government contracts.
In practice: The contract review identifies applicable CWHSSA clauses.
Coverage and obligations depend on the contract and statute.
U.S. Department of Labor ↗
CWI — Certified Welding Inspector
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An AWS certification designation for welding inspection personnel.
In practice: The quality plan identifies the assigned CWI.
American Welding Society ↗
Cx — Commissioning
Design phases & commissioning · Acronym or initialism · Industry-wide — A quality-focused process verifying and documenting that systems meet defined project requirements.
In practice: The Cx plan coordinates reviews, testing, training, and documentation.
Commissioning extends beyond equipment startup.
WBDG / NIBS ↗
CxA — Commissioning authority
Design phases & commissioning · Acronym or initialism · Industry-wide — A commonly used title for the party leading the commissioning process.
In practice: The owner appoints the CxA early in design.
Some standards and contracts prefer commissioning provider; authority follows the contract.
WBDG / NIBS ↗
CxP — Commissioning provider
Design phases & commissioning · Acronym or initialism · Industry-wide — The party providing the defined commissioning services.
In practice: The CxP maintains the issues log through functional testing.
The provider coordinates verification; it does not automatically replace designers or installers.
WBDG / NIBS ↗
CY — Cubic yard
Units & measurements · Unit or symbol · Industry-wide — A U.S. customary unit of volume equal to 27 cubic feet.
In practice: The concrete takeoff reports quantities in CY.
Earthwork volumes need a bank, loose, or compacted condition.
NIST ↗
DART — Days away, restricted, or transferred
Safety & occupational health · Acronym or initialism · Industry-wide — A recordkeeping category and related rate involving cases with days away, restricted work, or job transfer.
In practice: The safety report separates DART cases from all recordable cases.
DART rates typically use the 200,000-hour base; case counting follows recordkeeping rules.
OSHA ↗
DB — Design-build
Project delivery & contracts · Acronym or initialism · Industry-wide — A delivery approach in which one entity contracts with the owner for both design and construction.
In practice: The owner selects a DB team for the facility.
The allocation of design responsibility still depends on the contract.
Acquisition.gov ↗
DBA — Davis-Bacon Act
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A federal law establishing prevailing wage requirements for covered federal construction contracts.
In practice: The payroll team checks the DBA clauses and applicable wage determination.
DBA also commonly means doing business as in business names.
U.S. Department of Labor ↗
DBB — Design-bid-build
Project delivery & contracts · Acronym or initialism · Industry-wide — A delivery approach in which design is completed for bidding and construction is separately procured.
In practice: The agency completes design before soliciting DBB construction bids.
Actual packages may be phased; check the procurement documents.
Acquisition.gov ↗
DBRA — Davis-Bacon and Related Acts
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — The Davis-Bacon Act and related statutes extending prevailing wage requirements to covered federally assisted construction.
In practice: The contractor identifies DBRA obligations before assigning payroll classifications.
U.S. Department of Labor ↗
DC — Direct current
Electrical & fire protection · Acronym or initialism · Industry-wide — Electric current that flows in one direction.
In practice: The solar array produces DC before conversion by an inverter.
OSHA ↗
DCW — Domestic cold water
Mechanical & HVAC · Acronym or initialism · Industry-wide — The cold-water distribution system serving domestic plumbing uses.
In practice: The riser diagram labels the DCW main.
ASHRAE ↗
DD — Design development
Design phases & commissioning · Acronym or initialism · Industry-wide — A design phase refining the selected concept, systems, materials, and coordination.
In practice: The DD review resolves major equipment and space requirements.
AIA Contract Documents ↗
DDC — Direct digital control
Mechanical & HVAC · Acronym or initialism · Industry-wide — Control performed by programmable digital devices using measured inputs and control logic.
In practice: The DDC controller adjusts the heating valve.
ASHRAE ↗
DET — Detail
Drawings & specifications · Drawing abbreviation · Industry-wide — An enlarged or focused drawing of a particular assembly or condition.
In practice: The plan points to DET 4 for the parapet connection.
U.S. Department of Veterans Affairs ↗
DFU — Drainage fixture unit
Plumbing & utilities · Acronym or initialism · Industry-wide — A relative drainage loading unit assigned to plumbing fixtures under the applicable code.
In practice: The designer totals DFU values for a branch drain.
It is not a direct flow rate in gallons per minute.
International Code Council ↗
DHW — Domestic hot water
Mechanical & HVAC · Acronym or initialism · Industry-wide — Heated water provided for plumbing fixtures and domestic uses.
In practice: The DHW system serves lavatories and showers.
ASHRAE ↗
DIM — Dimension
Drawings & specifications · Drawing abbreviation · Industry-wide — A stated measurement controlling the size or location of a feature.
In practice: The installer checks the written DIM before fabrication.
U.S. Department of Veterans Affairs ↗
DIP — Ductile iron pipe
Plumbing & utilities · Acronym or initialism · Industry-wide — Pipe made from ductile iron, commonly used for buried water services and mains.
In practice: The utility drawing specifies DIP for the water main.
ASHRAE ↗
DL — Dead load
Structural steel, wood & welding · Acronym or initialism · Industry-wide — The load from permanent components and other specified permanent items.
In practice: The structural design includes cladding weight in DL.
AISC ↗
DOAS — Dedicated outdoor air system
Mechanical & HVAC · Acronym or initialism · Industry-wide — A system dedicated to conditioning and delivering outdoor ventilation air.
In practice: The DOAS handles ventilation while local units handle zone loads.
ASHRAE ↗
DOL — Department of Labor
Project team & organizations · Organization · U.S. specific — The federal department responsible for major labor and employment programs.
In practice: The payroll team reviews DOL guidance for a covered construction contract.
U.S. Department of Labor ↗
DOT — Department of Transportation
Project team & organizations · Organization · U.S. specific — A federal or state transportation department, depending on the document.
In practice: The plans use the state DOT's standard details.
Identify which department and jurisdiction the abbreviation denotes.
FHWA ↗
DWG — Drawing
Drawings & specifications · Drawing abbreviation · Industry-wide — A project drawing or, in some digital contexts, a particular CAD file format.
In practice: The RFI references the relevant DWG and detail number.
U.S. Department of Veterans Affairs ↗
DWV — Drain, waste, and vent
Plumbing & utilities · Acronym or initialism · Industry-wide — The plumbing system that removes wastewater and provides required venting.
In practice: The plumber coordinates DWV stacks with structural openings.
ASHRAE ↗
DX — Direct expansion
Mechanical & HVAC · Acronym or initialism · Industry-wide — Cooling in which refrigerant evaporates in a coil directly conditioning the air or other medium.
In practice: The AHU includes a DX cooling coil.
ASHRAE ↗
EA — Each
Drawings & specifications · Drawing abbreviation · Industry-wide — A count unit used for individual items in schedules and estimates.
In practice: The takeoff counts six access panels as EA.
NIST ↗
EA — Exhaust air
Mechanical & HVAC · Acronym or initialism · Industry-wide — Air discharged from a space or system to the outdoors or another designated discharge point.
In practice: The mechanical plan routes EA from the toilet room.
EA in a quantity schedule means each.
ASHRAE ↗
EAC — Estimate at completion
Estimating & project controls · Acronym or initialism · Industry-wide — The forecast total cost when the defined work is complete.
In practice: The PM updates EAC after reviewing remaining work.
Several forecasting methods exist; state the method and assumptions.
U.S. Department of Energy ↗
EAP — Emergency action plan
Safety & occupational health · Acronym or initialism · Industry-wide — A plan defining responsibilities and actions for workplace emergencies.
In practice: The orientation reviews the EAP and assembly locations.
OSHA ↗
EC — Electrical contractor
Electrical & fire protection · Acronym or initialism · Industry-wide — The contractor responsible for the assigned electrical scope.
In practice: The EC coordinates feeder routing with the mechanical trade.
OSHA ↗
EF — Each face
Drawings & specifications · Drawing abbreviation · Industry-wide — A note applying a reinforcement or other requirement to both faces of an element.
In practice: The wall note specifies vertical reinforcement EF.
EF can also mean exhaust fan on mechanical drawings.
American Concrete Institute ↗
EF — Exhaust fan
Mechanical & HVAC · Acronym or initialism · Industry-wide — A fan serving an exhaust air system.
In practice: The roof plan locates EF-2 over the service area.
EF on reinforcement drawings often means each face.
ASHRAE ↗
EG — Existing grade
Drawings & specifications · Drawing abbreviation · Industry-wide — The ground surface or elevation before the proposed work.
In practice: The section shows EG beneath the proposed embankment.
U.S. Department of Veterans Affairs ↗
EGC — Equipment grounding conductor
Electrical & fire protection · Acronym or initialism · Industry-wide — A conductive path connecting equipment metal parts into the grounding and bonding system.
In practice: The feeder detail identifies the EGC.
Do not confuse an EGC with a neutral conductor.
OSHA ↗
EIFS — Exterior insulation and finish system
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — An exterior wall cladding system combining insulation with reinforced base and finish coats.
In practice: The facade detail coordinates EIFS with flashings and drainage.
The complete approved assembly determines performance.
ASHRAE ↗
EJ — Expansion joint
Drawings & specifications · Drawing abbreviation · Industry-wide — A joint intended to accommodate movement from temperature or other dimensional change.
In practice: The facade detail identifies a continuous EJ.
Joint design and sealant selection depend on the assembly.
U.S. Department of Veterans Affairs ↗
EL — Elevation
Drawings & specifications · Drawing abbreviation · Industry-wide — A vertical level or an upright view of a building face, depending on context.
In practice: The section labels the landing EL beside the stair.
A number beside EL often indicates a level; a view title may indicate an elevation drawing.
U.S. Department of Veterans Affairs ↗
EMR — Experience modification rate
Safety & occupational health · Acronym or initialism · Industry-wide — A workers' compensation insurance factor reflecting an employer's loss experience under the applicable rating system.
In practice: The bid submission requests the contractor's EMR documentation.
It is an insurance measure, not the same as an OSHA injury rate.
NCCI ↗
EMT — Electrical metallic tubing
Electrical & fire protection · Acronym or initialism · Industry-wide — A thin-wall metal raceway for electrical conductors.
In practice: The electrical specification permits EMT in the designated interior area.
ASHRAE ↗
EOR — Engineer of record
Project team & organizations · Acronym or initialism · Industry-wide — The engineer identified as responsible for the engineering design within the assigned scope.
In practice: The contractor forwards a structural design question to the EOR.
AISC ↗
EOT — Extension of time
Estimating & project controls · Acronym or initialism · Industry-wide — An approved or requested adjustment to a contractual completion period.
In practice: The contractor submits an EOT request with supporting schedule analysis.
Entitlement and notice requirements depend on the contract.
Acquisition.gov ↗
EPA — Environmental Protection Agency
Project team & organizations · Organization · U.S. specific — The federal agency administering major U.S. environmental programs.
In practice: The environmental lead identifies whether EPA or a state administers the permit.
U.S. EPA ↗
EPC — Engineering, procurement, and construction
Project delivery & contracts · Acronym or initialism · Industry-wide — A project delivery arrangement combining engineering, purchasing, and construction responsibilities.
In practice: An EPC contractor coordinates process equipment and field installation.
Acquisition.gov ↗
EPD — Environmental product declaration
Environment & sustainability · Acronym or initialism · Industry-wide — A standardized declaration reporting environmental information for a product based on life-cycle assessment rules.
In practice: The submittal includes an EPD for the selected concrete mixture.
An EPD reports data; it does not by itself establish that a product is environmentally preferable.
U.S. Green Building Council ↗
EPDM — Ethylene propylene diene monomer
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A synthetic rubber used in roofing membranes, seals, and other building products.
In practice: The roof detail specifies an EPDM membrane.
NRCA ↗
EQ — Equal
Drawings & specifications · Drawing abbreviation · Industry-wide — A drawing instruction indicating equal dimensions, spacing, or distribution.
In practice: The ceiling plan marks three panel widths EQ.
U.S. Department of Veterans Affairs ↗
ERV — Energy recovery ventilator
Mechanical & HVAC · Acronym or initialism · Industry-wide — Ventilation equipment exchanging sensible and latent energy between air streams under its design conditions.
In practice: The DOAS includes an ERV section.
ASHRAE ↗
ESAL — Equivalent single axle load
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A pavement design measure expressing traffic loading in terms of an equivalent reference axle.
In practice: The pavement study estimates ESAL demand over the design period.
FHWA ↗
ESC — Erosion and sediment control
Environment & sustainability · Acronym or initialism · Industry-wide — Measures that limit soil erosion and keep sediment from leaving disturbed areas.
In practice: The ESC inspection checks perimeter controls and exposed slopes.
U.S. EPA ↗
ESP — External static pressure
Mechanical & HVAC · Acronym or initialism · Industry-wide — The static pressure available or required outside the equipment boundary defined by the rating or schedule.
In practice: The fan selection checks the scheduled ESP against duct losses.
ASHRAE ↗
ETC — Estimate to complete
Estimating & project controls · Acronym or initialism · Industry-wide — The forecast cost required to finish the remaining work.
In practice: The controls team revises ETC for the unawarded packages.
U.S. Department of Energy ↗
EV — Earned value
Estimating & project controls · Acronym or initialism · Industry-wide — The budgeted value of work actually completed under the measurement method.
In practice: The team calculates EV using accepted progress rules.
Earned value is not the same as money billed or revenue received.
U.S. Department of Energy ↗
EVM — Earned value management
Estimating & project controls · Acronym or initialism · Industry-wide — A method integrating scope, schedule, and cost using a defined performance baseline.
In practice: The project controls team compares earned value with cost and plan.
U.S. Department of Energy ↗
EVSE — Electric vehicle supply equipment
Electrical & fire protection · Acronym or initialism · Industry-wide — Equipment that delivers electrical energy to an electric vehicle and provides the specified control and protection functions.
In practice: The electrical design includes EVSE load and circuit information.
ASHRAE ↗
EW — Each way
Drawings & specifications · Drawing abbreviation · Industry-wide — A note applying a reinforcement or spacing requirement in both directions.
In practice: The slab reinforcement is specified EW.
American Concrete Institute ↗
f'c — Specified compressive strength of concrete
Concrete & masonry · Unit or symbol · Industry-wide — The concrete compressive strength required at the stated test age and under the specified test method.
In practice: The structural notes specify f'c for each concrete class.
The test age and acceptance criteria matter as much as the number.
American Concrete Institute ↗
FA — Fire alarm
Electrical & fire protection · Acronym or initialism · Industry-wide — The building system for detecting, notifying, and communicating specified fire or emergency conditions.
In practice: The FA drawings coordinate devices and pathways.
NFPA ↗
FACP — Fire alarm control panel
Electrical & fire protection · Acronym or initialism · Industry-wide — The control equipment receiving initiating signals and managing fire-alarm system outputs.
In practice: The riser diagram locates the FACP.
NFPA ↗
FAR — Federal Acquisition Regulation
Codes & accessibility · Code, standard or program · U.S. specific — The principal regulation governing acquisition by U.S. federal executive agencies, with agency supplements and contract clauses where applicable.
In practice: The federal construction solicitation identifies relevant FAR clauses.
Check the actual solicitation, contract, and applicable agency supplement.
Acquisition.gov ↗
FCAW — Flux cored arc welding
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An arc welding process using a tubular flux-filled electrode, with shielding determined by the process variant.
In practice: The fabricator selects the specified FCAW procedure.
Self-shielded and gas-shielded variants have different requirements.
American Welding Society ↗
FCO — Floor cleanout
Plumbing & utilities · Acronym or initialism · Industry-wide — A drainage cleanout accessed through the floor surface.
In practice: The finish plan coordinates access to the FCO.
ASHRAE ↗
FCU — Fan-coil unit
Mechanical & HVAC · Acronym or initialism · Industry-wide — A local air-conditioning unit containing a fan and heating or cooling coil.
In practice: The room schedule identifies an FCU above the ceiling.
FCU can mean fixture connection unit in some plumbing legends; check context.
ASHRAE ↗
FD — Floor drain
Plumbing & utilities · Acronym or initialism · Industry-wide — A plumbing fixture receiving drainage at the floor.
In practice: The mechanical room floor slopes toward the FD.
FD in an HVAC legend can mean fire damper.
ASHRAE ↗
FD — Fire damper
Plumbing & utilities · Acronym or initialism · Industry-wide — A listed damper intended to restrict fire passage through an air-distribution opening under specified conditions.
In practice: The mechanical detail shows an FD at the rated wall penetration.
A fire damper and a floor drain are unrelated uses of FD.
NFPA ↗
FDC — Fire department connection
Electrical & fire protection · Acronym or initialism · Industry-wide — A connection allowing the fire department to supply water to a fire-protection system.
In practice: The site plan preserves access to the FDC.
NFPA ↗
FF — Finished floor
Drawings & specifications · Drawing abbreviation · Industry-wide — The completed walking surface, often used as a dimensional reference on drawings.
In practice: The section measures the sill height from FF.
FF also denotes floor flatness in concrete testing; read the legend.
U.S. Department of Veterans Affairs ↗
FF — Floor flatness
Concrete & masonry · Acronym or initialism · Industry-wide — An F-number measure describing short-range variation in a concrete floor surface.
In practice: The flooring report lists tested FF results.
FF on drawings can instead mean finished floor; testing follows the specified method.
American Concrete Institute ↗
FF — Finish-to-finish
Estimating & project controls · Acronym or initialism · Industry-wide — A dependency relating the successor's finish to the predecessor's finish with any stated lag.
In practice: The schedule links cleanup FF to the final installation activity.
FF also means finished floor or floor flatness in other contexts.
FHWA ↗
FFE — Finished floor elevation
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation assigned to the top of the completed floor at a stated location.
In practice: The site plan sets the first-floor FFE relative to the survey datum.
Confirm the datum and whether multiple finished floor elevations occur.
U.S. Department of Veterans Affairs ↗
FFP — Firm-fixed-price
Project delivery & contracts · Acronym or initialism · Industry-wide — A contract pricing arrangement with a price generally not adjusted for the contractor's actual cost experience.
In practice: The agency awards an FFP contract for a defined scope.
Acquisition.gov ↗
FG — Finished grade
Drawings & specifications · Drawing abbreviation · Industry-wide — The designed final elevation or surface of exterior earthwork and landscaping.
In practice: The grading plan slopes FG away from the building.
Some legends use finish grade as the expansion.
U.S. Department of Veterans Affairs ↗
FHWA — Federal Highway Administration
Project team & organizations · Organization · U.S. specific — A U.S. Department of Transportation agency supporting federal highway programs.
In practice: The road project references FHWA guidance on work-zone planning.
FHWA ↗
FL — Floor levelness
Concrete & masonry · Acronym or initialism · Industry-wide — An F-number measure describing variation in a concrete floor's level over the test spacing.
In practice: The slab acceptance report lists FL values for the test areas.
F-number levelness is not the same as a single survey elevation.
American Concrete Institute ↗
FLSA — Fair Labor Standards Act
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — The federal law addressing minimum wage, overtime, recordkeeping, and child labor for covered employment.
In practice: The employer checks FLSA treatment of recorded work hours.
U.S. Department of Labor ↗
FMC — Flexible metal conduit
Electrical & fire protection · Acronym or initialism · Industry-wide — A flexible metal raceway used where the installation calls for flexibility.
In practice: The connection detail uses FMC at the equipment.
ASHRAE ↗
FOPS — Falling-object protective structure
Safety & occupational health · Acronym or initialism · Industry-wide — A structure intended to protect an equipment operator from specified falling objects.
In practice: The machine selection considers the required FOPS rating.
A rating does not cover every possible impact scenario.
OSHA ↗
FP — Fire protection
Electrical & fire protection · Acronym or initialism · Industry-wide — Systems and measures intended to limit fire effects, often used for the sprinkler trade package.
In practice: The FP model coordinates sprinkler mains with ducts.
NFPA ↗
FPT — Functional performance test
Design phases & commissioning · Acronym or initialism · Industry-wide — A test exercising system operation against defined functional requirements.
In practice: The team performs an FPT of the air-handling sequence.
Test procedures, prerequisites, acceptance, and retesting belong in the commissioning plan.
WBDG / NIBS ↗
FRC — Fiber-reinforced concrete
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete containing discrete fibers intended to improve specified performance characteristics.
In practice: The slab mix includes FRC for the specified application.
Fibers do not automatically replace all conventional reinforcement.
American Concrete Institute ↗
FRP — Fiber-reinforced polymer
Concrete & masonry · Acronym or initialism · Industry-wide — A composite material combining fibers with a polymer matrix.
In practice: The repair design uses externally bonded FRP reinforcement.
Fire, durability, bond, and installation requirements depend on the system.
American Concrete Institute ↗
FRP — Fiberglass-reinforced plastic panel
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — Common trade shorthand for durable fiberglass-reinforced wall panels used in wet or service areas.
In practice: The finish schedule calls for FRP panels in the wash area.
This product meaning is narrower than the structural composite category.
ASHRAE ↗
FS — Finish-to-start
Estimating & project controls · Acronym or initialism · Industry-wide — A schedule dependency in which the successor's start depends on the predecessor's finish, with any stated lag.
In practice: The schedule links cure completion FS to the next operation.
Dates also depend on calendars, constraints, and other logic.
FHWA ↗
FSD — Fire/smoke damper
Plumbing & utilities · Acronym or initialism · Industry-wide — A combination damper intended to perform both fire and smoke control functions.
In practice: The controls sequence coordinates the FSD actuator and alarm interface.
Installation, access, and testing must suit the listed assembly.
NFPA ↗
FTE — Full-time equivalent
Workforce, payroll & insurance · Acronym or initialism · Industry-wide — A staffing measure converting work hours to an equivalent number of full-time positions under a defined basis.
In practice: The staffing plan states the hours used to calculate FTE.
Different programs use different full-time definitions.
TimeTrex ↗
FV — Field verify
Drawings & specifications · Drawing abbreviation · Industry-wide — A note asking the responsible party to check an existing condition on site.
In practice: The millwork dimensions are marked FV.
U.S. Department of Veterans Affairs ↗
GBCI — Green Business Certification Inc.
Environment & sustainability · Acronym or initialism · Industry-wide — An organization administering certification and credentialing for LEED and other programs.
In practice: The project team prepares the required GBCI certification submission.
GBCI ↗
GC — General contractor
Project team & organizations · Acronym or initialism · Industry-wide — The contractor responsible for coordinating and delivering the overall construction work under its agreement.
In practice: The GC coordinates site access for the trades.
GC may also refer to general conditions in estimates and contracts.
AIA Contract Documents ↗
GC — General conditions
Project team & organizations · Acronym or initialism · Industry-wide — Contract provisions governing project administration; also used for certain project support costs in estimates.
In practice: The estimate lists temporary facilities under GC costs.
Distinguish contract general conditions from the cost category in a budget.
AIA Contract Documents ↗
GEC — Grounding electrode conductor
Electrical & fire protection · Acronym or initialism · Industry-wide — The conductor connecting the system or equipment to the grounding electrode system as required.
In practice: The service detail sizes the GEC.
OSHA ↗
GFCI — Ground-fault circuit interrupter
Electrical & fire protection · Acronym or initialism · Industry-wide — A protective device that interrupts a circuit under defined ground-fault conditions to reduce shock risk.
In practice: The temporary-power plan identifies required GFCI protection.
Protection, testing, and installation follow applicable requirements.
OSHA ↗
GFRP — Glass fiber-reinforced polymer
Concrete & masonry · Acronym or initialism · Industry-wide — A composite of glass fibers and polymer resin used in selected reinforcement or building products.
In practice: The design specifies GFRP bars for a corrosive exposure.
Design properties differ from steel reinforcement.
American Concrete Institute ↗
GGBFS — Ground granulated blast-furnace slag
Concrete & masonry · Acronym or initialism · Industry-wide — A finely ground ironmaking by-product used as a cementitious material in concrete.
In practice: The mix design includes GGBFS as a portion of the binder.
Slag cement is common terminology in U.S. specifications.
American Concrete Institute ↗
GHS — Globally Harmonized System of Classification and Labelling of Chemicals
Safety & occupational health · Acronym or initialism · Industry-wide — An international framework for communicating chemical hazards through classification, labels, and safety data sheets.
In practice: The safety training explains GHS hazard pictograms.
Jurisdictions implement the framework through their own requirements.
OSHA ↗
GIS — Geographic information system
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A system for storing, analyzing, and displaying information tied to geographic locations.
In practice: The utility team maps assets in a GIS.
USGS ↗
GLT — Glue-laminated timber
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An engineered wood member made by bonding lumber laminations with grain mainly along its length.
In practice: The roof spans between GLT beams.
Commonly called glulam.
APA – The Engineered Wood Association ↗
GMAW — Gas metal arc welding
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An arc welding process using a continuously fed wire electrode and externally supplied shielding gas.
In practice: The shop uses an approved GMAW procedure.
MIG is common shop terminology, though shielding gas and transfer mode vary.
American Welding Society ↗
GMP — Guaranteed maximum price
Project delivery & contracts · Acronym or initialism · Industry-wide — A contractual price ceiling subject to the agreement's scope, allowances, exclusions, and adjustment terms.
In practice: The team reconciles the scope before agreeing on the GMP.
A GMP is not a promise that every later owner change is included.
AIA Contract Documents ↗
GNSS — Global navigation satellite system
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The collective term for satellite navigation systems used for positioning.
In practice: The rover uses GNSS signals from multiple constellations.
NOAA / NGS ↗
GPM — Gallons per minute
Plumbing & utilities · Unit or symbol · Industry-wide — A volumetric liquid flow rate used in U.S. building-system schedules.
In practice: The pump schedule lists a design flow of 50 GPM.
Confirm U.S. gallons when comparing international data; 1 U.S. gallon is 3.785411784 liters.
NIST ↗
GPS — Global Positioning System
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A U.S. satellite positioning system used in surveying and equipment guidance.
In practice: The survey crew uses GPS observations for control work.
NOAA / NGS ↗
GSA — General Services Administration
Project team & organizations · Organization · U.S. specific — A federal agency managing many federal facilities and acquisitions.
In practice: The design team reviews the GSA project deliverables.
GSA ↗
GTAW — Gas tungsten arc welding
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An arc welding process using a nonconsumable tungsten electrode and shielding gas.
In practice: The piping WPS specifies GTAW for a root pass.
Often called TIG welding.
American Welding Society ↗
GWB — Gypsum wallboard
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A gypsum panel used for wall or ceiling surfaces in specified assemblies.
In practice: The wall type lists two layers of GWB on each side.
U.S. Department of Veterans Affairs ↗
GWP — Global warming potential
Environment & sustainability · Acronym or initialism · Industry-wide — A measure comparing a greenhouse gas's climate effect with carbon dioxide over a defined time horizon.
In practice: The EPD reports GWP for the declared product unit.
Compare values only when scope, units, and assessment rules are compatible.
U.S. Green Building Council ↗
H2S — Hydrogen sulfide
Safety & occupational health · Chemical symbol · Industry-wide — A toxic, flammable gas that can occur in sewers and other environments.
In practice: The confined-space assessment considers possible H2S exposure.
Odor is not a reliable warning or exposure measurement.
NIOSH / CDC ↗
HazCom — Hazard communication
Safety & occupational health · Acronym or initialism · Industry-wide — The workplace program for communicating chemical hazards through labels, safety data sheets, and training.
In practice: The site HazCom program covers products brought by subcontractors.
Often abbreviated HCS when referring to OSHA's standard.
OSHA ↗
HDD — Horizontal directional drilling
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A trenchless method for installing a bore or utility along a planned curved path.
In practice: The utility contractor proposes HDD beneath the roadway.
FHWA ↗
HDPE — High-density polyethylene
Plumbing & utilities · Acronym or initialism · Industry-wide — A thermoplastic used in water, drainage, and other utility pipe systems.
In practice: The utility plan specifies fused HDPE pipe.
Pipe dimension ratio, pressure rating, and joining requirements are project-specific.
ASHRAE ↗
HEPA — High-efficiency particulate air
Mechanical & HVAC · Acronym or initialism · Industry-wide — A category of high-efficiency air filtration meeting specified test criteria.
In practice: The containment equipment uses a specified HEPA filter.
Filter efficiency alone does not establish complete containment-system performance.
ASHRAE ↗
HHW — Heating hot water
Mechanical & HVAC · Acronym or initialism · Industry-wide — Heated water circulated through a hydronic space-heating system.
In practice: The HHW loop serves the air-handling heating coils.
Distinguish building heating water from domestic hot water.
ASHRAE ↗
HLL — Horizontal lifeline
Safety & occupational health · Acronym or initialism · Industry-wide — A horizontal anchorage line forming part of a designed fall-protection system.
In practice: The roof plan identifies the approved HLL system.
System loads and clearance must be evaluated by appropriately qualified personnel.
OSHA ↗
HMA — Hot-mix asphalt
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Asphalt paving mixture produced and placed at elevated temperatures.
In practice: The paving plan identifies an HMA surface course.
Mix properties and temperatures depend on the specified system.
FHWA ↗
HRV — Heat recovery ventilator
Mechanical & HVAC · Acronym or initialism · Industry-wide — Ventilation equipment primarily exchanging sensible heat between air streams.
In practice: The residential design specifies an HRV.
ASHRAE ↗
HSS — Hollow structural section
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A structural steel member with a hollow circular, square, or rectangular cross section.
In practice: The canopy columns are specified as square HSS.
Match the exact section dimensions, wall thickness, grade, and specification.
AISC ↗
HVAC — Heating, ventilation, and air conditioning
Mechanical & HVAC · Acronym or initialism · Industry-wide — Building systems that provide heating, cooling, air movement, and ventilation.
In practice: The HVAC package includes equipment, ductwork, piping, and controls.
The exact package boundaries depend on the project.
ASHRAE ↗
IAQ — Indoor air quality
Environment & sustainability · Acronym or initialism · Industry-wide — The condition of indoor air as it relates to occupants' health and comfort.
In practice: The construction IAQ plan addresses dust and moisture before occupancy.
U.S. EPA ↗
IBC — International Building Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing building design and construction.
In practice: The code summary identifies the adopted IBC edition.
Local adoption and amendments determine enforceable requirements.
International Code Council ↗
ICC — International Code Council
Project team & organizations · Organization · U.S. specific — An organization publishing model building and related codes.
In practice: The permit set identifies the adopted ICC code edition.
International Code Council ↗
ICF — Insulating concrete form
Concrete & masonry · Acronym or initialism · Industry-wide — A formwork system, commonly left in place, that combines concrete placement with insulation.
In practice: The residential wall system uses ICF forms and reinforced concrete.
The form product is only one part of the structural and enclosure assembly.
U.S. Department of Energy ↗
IDLH — Immediately dangerous to life or health
Safety & occupational health · Acronym or initialism · Industry-wide — A NIOSH exposure condition or value relevant to escape impairment and serious health danger.
In practice: The respiratory protection assessment considers IDLH conditions.
IDLH values are not routine acceptable exposure targets.
NIOSH / CDC ↗
IECC — International Energy Conservation Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing building energy efficiency.
In practice: The energy compliance documents identify the applicable IECC provisions.
International Code Council ↗
IFB — Invitation for bids
Project delivery & contracts · Acronym or initialism · Industry-wide — A formal invitation to submit bids for specified work under stated bidding rules.
In practice: The agency publishes an IFB with plans and a bid schedule.
Acquisition.gov ↗
IFC — International Fire Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing fire prevention and fire-safety conditions.
In practice: The site fire-access plan references the adopted IFC.
IFC also means issued for construction or Industry Foundation Classes.
International Code Council ↗
IFC — Industry Foundation Classes
BIM & digital coordination · Digital standard · Industry-wide — An open data schema for exchanging and sharing built-asset information.
In practice: The design team exports an IFC model for coordination.
IFC also means issued for construction or International Fire Code.
buildingSMART International ↗
IFC — Issued for construction
Design phases & commissioning · Acronym or initialism · Industry-wide — A document status indicating issuance for construction use under the project's control process.
In practice: The superintendent checks that the field set carries the correct IFC revision.
The stamp is not a substitute for required permits or contractual authorization.
AIA Contract Documents ↗
IFT — Issued for tender
Design phases & commissioning · Acronym or initialism · Industry-wide — A document status indicating an issue for bidding or tendering.
In practice: The estimator prepares the bid from the IFT set.
U.S. projects may instead say issued for bid; status terminology varies.
AIA Contract Documents ↗
IGU — Insulating glass unit
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A sealed glazing assembly of multiple panes separated by a spacer and enclosed space.
In practice: The window schedule specifies the IGU makeup.
ASHRAE ↗
IIC — Impact insulation class
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A single-number rating for impact sound transmission through a floor-ceiling assembly.
In practice: The flooring submittal reports the tested IIC assembly.
Field performance and tested laboratory ratings can differ.
ASHRAE ↗
IMC — Intermediate metal conduit
Electrical & fire protection · Acronym or initialism · Industry-wide — A metal raceway with dimensions and construction between common tubing and rigid conduit systems.
In practice: The specification allows IMC for selected exposed runs.
ASHRAE ↗
IMC — International Mechanical Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing mechanical systems.
In practice: The mechanical notes identify the adopted IMC edition.
IMC also means intermediate metal conduit in electrical specifications.
International Code Council ↗
INV — Invert elevation
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The elevation of the inside bottom of a pipe or channel at a stated location.
In practice: The drainage profile labels the INV at the structure outlet.
Some legends use INV simply for invert; confirm the datum and units.
U.S. Department of Veterans Affairs ↗
IPC — International Plumbing Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing plumbing systems.
In practice: The plumbing design cites the adopted IPC edition.
International Code Council ↗
IPD — Integrated project delivery
Project delivery & contracts · Acronym or initialism · Industry-wide — A collaborative delivery approach that coordinates owner, designer, and builder interests early in the project.
In practice: The IPD team jointly evaluates constructability and cost.
Some projects use multiparty contracts; collaborative practices alone do not define contract terms.
AIA Contract Documents ↗
IRC — International Residential Code
Codes & accessibility · Code, standard or program · U.S. specific — An ICC model code addressing qualifying detached one- and two-family dwellings and townhouses.
In practice: The permit drawings identify whether the work falls under the adopted IRC.
International Code Council ↗
ITB — Invitation to bid
Project delivery & contracts · Acronym or initialism · Industry-wide — A request for contractors or suppliers to submit a bid on described work.
In practice: The GC sends an ITB to electrical subcontractors.
Acquisition.gov ↗
ITP — Inspection and test plan
Quality & inspection · Acronym or initialism · Industry-wide — A plan identifying inspections, tests, acceptance criteria, and responsible parties for the work.
In practice: The ITP identifies witness and hold points before concealment.
AISC ↗
JHA — Job hazard analysis
Safety & occupational health · Acronym or initialism · Industry-wide — A structured review of job steps, associated hazards, and protective measures.
In practice: The crew reviews the JHA before beginning a new task.
OSHA ↗
JMF — Job mix formula
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The approved target proportions and properties for a paving mixture.
In practice: The plant operates to the accepted JMF and specified tolerances.
FHWA ↗
JSA — Job safety analysis
Safety & occupational health · Acronym or initialism · Industry-wide — A task analysis identifying hazards and ways to control them, often used similarly to JHA.
In practice: The foreperson updates the JSA when the work sequence changes.
Terminology and forms vary among employers.
OSHA ↗
kcmil — Thousand circular mils
Electrical & fire protection · Unit or symbol · Industry-wide — A conductor cross-sectional area unit commonly used for larger cables.
In practice: The feeder schedule specifies a 500 kcmil conductor.
Legacy drawings may use MCM for the same unit.
NIST ↗
ksi — Kips per square inch
Units & measurements · Unit or symbol · Industry-wide — A stress unit equal to 1,000 pounds per square inch.
In practice: The steel material schedule states yield strength in ksi.
A kip is 1,000 pounds-force, not 1,000 pounds of mass in a general physics calculation.
NIST ↗
kVA — Kilovolt-ampere
Units & measurements · Unit or symbol · Industry-wide — A unit of apparent electrical power equal to 1,000 volt-amperes.
In practice: The transformer schedule lists its kVA rating.
Real power in kW depends on power factor and operating conditions.
NIST ↗
kW — Kilowatt
Units & measurements · Unit or symbol · Industry-wide — A unit of power equal to 1,000 watts.
In practice: The equipment schedule lists a 15 kW electrical input.
Power and energy are different quantities.
NIST ↗
kWh — Kilowatt-hour
Units & measurements · Unit or symbol · Industry-wide — A unit of energy equal to one kilowatt of power sustained for one hour.
In practice: The meter records monthly consumption in kWh.
A kWh is a unit of energy, not an instantaneous demand.
NIST ↗
LCA — Life-cycle assessment
Environment & sustainability · Acronym or initialism · Industry-wide — A method assessing environmental impacts across defined stages of a product or building life cycle.
In practice: The design team compares alternatives using an LCA with consistent boundaries.
Results depend on functional unit, boundaries, assumptions, and data quality.
U.S. EPA ↗
LCCA — Life-cycle cost analysis
Estimating & project controls · Acronym or initialism · Industry-wide — An economic comparison including relevant costs over a defined analysis period.
In practice: The owner compares roof options using LCCA.
LCCA addresses costs; LCA assesses environmental impacts.
FHWA ↗
LCY — Loose cubic yard
Civil, survey & earthwork · Unit or symbol · Industry-wide — A cubic yard of excavated or handled material in a loose condition.
In practice: The haul plan converts bank excavation into estimated LCY.
FHWA ↗
LD — Liquidated damages
Project delivery & contracts · Acronym or initialism · Industry-wide — A contractually stated amount used for a specified breach, often late completion, subject to applicable law.
In practice: The scheduler reviews the LD clause alongside milestone dates.
Enforceability and application depend on the agreement and law.
Acquisition.gov ↗
LEED — Leadership in Energy and Environmental Design
Environment & sustainability · Acronym or initialism · Industry-wide — A green building rating system administered through the USGBC and certification framework.
In practice: The project tracks documentation for targeted LEED credits.
A product alone does not make a building LEED certified.
U.S. Green Building Council ↗
LEL — Lower explosive limit
Safety & occupational health · Acronym or initialism · Industry-wide — The minimum fuel concentration in air capable of propagating flame under specified conditions.
In practice: The atmospheric test report states results as percent LEL.
Instrument readings, calibration gas, and oxygen conditions require competent interpretation.
NIOSH / CDC ↗
LF — Linear foot
Units & measurements · Unit or symbol · Industry-wide — A length measurement of one foot along an item.
In practice: The takeoff records base trim in LF.
State whether allowances, waste, and accessories are included.
NIST ↗
LFL — Lower flammable limit
Safety & occupational health · Acronym or initialism · Industry-wide — The lower fuel concentration boundary for flame propagation under stated conditions.
In practice: The safety data sheet lists an LFL value for the product.
LEL and LFL are commonly used for the same lower flammability boundary.
NIOSH / CDC ↗
LFMC — Liquidtight flexible metal conduit
Electrical & fire protection · Acronym or initialism · Industry-wide — Flexible metal conduit with an outer covering providing the specified liquidtight protection.
In practice: The motor connection uses LFMC with listed fittings.
ASHRAE ↗
LiDAR — Light detection and ranging
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A ranging method using laser measurements to capture positions and surfaces.
In practice: A LiDAR scan records the existing facade geometry.
Point-cloud accuracy and coverage must suit the intended use.
NOAA / NGS ↗
LL — Liquid limit
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The moisture content at a defined boundary between plastic and liquid soil behavior in a standardized test.
In practice: The laboratory reports LL for the clay sample.
On structural plans, LL usually means live load.
FHWA ↗
LL — Live load
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A variable load associated with occupancy or use under the governing design criteria.
In practice: The floor design uses the specified office LL.
LL in a soil laboratory report means liquid limit.
AISC ↗
LOD — Level of development
BIM & digital coordination · Acronym or initialism · Industry-wide — A framework describing the reliability and development of model elements for specified uses.
In practice: The BIM deliverable sets LOD requirements by element and milestone.
Level of development is not simply visual detail; some documents use LOD for level of detail.
BIMForum ↗
LOI — Letter of intent
Project delivery & contracts · Acronym or initialism · Industry-wide — A letter recording an intended arrangement or proposed next step before a fuller agreement.
In practice: The parties issue an LOI for early procurement discussions.
Whether provisions bind the parties depends on the wording and applicable law.
Acquisition.gov ↗
LOTO — Lockout/tagout
Safety & occupational health · Acronym or initialism · Industry-wide — Procedures using locks, tags, and other required measures to control hazardous energy during servicing or work.
In practice: The crew follows the applicable LOTO procedure before maintenance.
Construction tasks may be governed by task-specific energy-control provisions; identify the applicable rules.
OSHA ↗
LPS — Last Planner System
Estimating & project controls · Acronym or initialism · Industry-wide — A collaborative production planning and control system associated with Lean construction.
In practice: The team uses LPS to make work ready before weekly commitments.
Lean Construction Institute ↗
LRFD — Load and resistance factor design
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A design approach using factored loads and factored resistance to check limit states.
In practice: The steel calculation uses LRFD combinations.
Do not mix ASD loads or capacities with LRFD values.
AISC ↗
LSL — Laminated strand lumber
Structural steel, wood & welding · Acronym or initialism · Industry-wide — Engineered structural lumber made from oriented wood strands bonded into a member.
In practice: The wall system uses LSL rim board.
APA – The Engineered Wood Association ↗
LVL — Laminated veneer lumber
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An engineered wood product made by bonding wood veneers, generally with grain oriented along the member.
In practice: The opening header is specified as LVL.
APA – The Engineered Wood Association ↗
LVT — Luxury vinyl tile
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A commercial term for decorative layered vinyl flooring products.
In practice: The designer specifies an LVT plank product.
The term alone does not define wear layer, installation, or performance.
ASHRAE ↗
MBH — Thousand British thermal units per hour
Units & measurements · Unit or symbol · Industry-wide — A common U.S. HVAC capacity abbreviation meaning 1,000 Btu per hour.
In practice: The boiler schedule lists 200 MBH output.
In this usage M means one thousand, not one million.
ASHRAE ↗
MCC — Motor control center
Electrical & fire protection · Acronym or initialism · Industry-wide — An assembly grouping motor controllers and related protective equipment.
In practice: The electrical room layout reserves space for the MCC.
ASHRAE ↗
MDD — Maximum dry density
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The highest dry density obtained for a soil under a specified laboratory compaction method.
In practice: Field density is compared with the specified percentage of MDD.
Different compaction test methods can produce different reference values.
FHWA ↗
MEP — Mechanical, electrical, and plumbing
Project team & organizations · Acronym or initialism · Industry-wide — The three major building-services disciplines frequently coordinated together.
In practice: The MEP team resolves conflicts above the corridor ceiling.
ASHRAE ↗
MEPF — Mechanical, electrical, plumbing, and fire protection
Project team & organizations · Acronym or initialism · Industry-wide — An expanded building-services grouping that explicitly includes fire protection.
In practice: The MEPF coordination model includes sprinkler mains.
ASHRAE ↗
MERV — Minimum efficiency reporting value
Mechanical & HVAC · Acronym or initialism · Industry-wide — A filter efficiency rating under the applicable ASHRAE test procedure.
In practice: The filter schedule specifies a MERV rating and pressure-drop limits.
ASHRAE ↗
MEWP — Mobile elevating work platform
Safety & occupational health · Acronym or initialism · Industry-wide — A category of powered equipment used to elevate workers to work positions.
In practice: The lift plan identifies the MEWP type and required familiarization.
Use the manufacturer's instructions and applicable equipment standard.
OSHA ↗
MH — Manhole
Civil, survey & earthwork · Acronym or initialism · Industry-wide — An access structure for inspection or maintenance of underground utilities.
In practice: The utility profile identifies the MH rim and invert elevations.
U.S. Department of Veterans Affairs ↗
MO — Masonry opening
Drawings & specifications · Drawing abbreviation · Industry-wide — The opening formed within masonry to receive a frame or other assembly.
In practice: The mason confirms the MO before laying the jamb.
U.S. Department of Veterans Affairs ↗
MOT — Maintenance of traffic
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Planning and operations used to maintain traffic movement and safety during work.
In practice: The contractor submits an MOT plan for the bridge staging.
Agency terminology differs; confirm the required plan format.
FHWA ↗
MPa — Megapascal
Units & measurements · Unit or symbol · Industry-wide — An SI pressure or stress unit equal to one million pascals.
In practice: An imported test report gives concrete strength in MPa.
Convert units before comparing specifications and test results.
NIST ↗
MS4 — Municipal separate storm sewer system
Environment & sustainability · Acronym or initialism · Industry-wide — A publicly owned stormwater conveyance system covered by the relevant regulatory definition.
In practice: The site discharges toward a regulated MS4.
An MS4 is distinct from a combined sanitary and storm sewer system.
U.S. EPA ↗
MSDS — Material safety data sheet
Safety & occupational health · Legacy terminology · Industry-wide — The older name for chemical hazard information sheets preceding standardized SDS terminology.
In practice: The archive contains a document labeled MSDS.
Request the current SDS for current product decisions.
OSHA ↗
MT — Magnetic particle testing
Quality & inspection · Acronym or initialism · Industry-wide — A nondestructive method detecting suitable surface and near-surface discontinuities in ferromagnetic materials.
In practice: The inspection plan requires MT at selected weld locations.
It is not applicable to every metal or defect type.
American Welding Society ↗
MUTCD — Manual on Uniform Traffic Control Devices
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The U.S. manual establishing standards for traffic control devices on roads open to public travel.
In practice: The traffic engineer identifies the applicable MUTCD edition and supplements.
Use the edition and jurisdictional requirements applicable to the project.
FHWA ↗
N-value — SPT blow count
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The reported penetration resistance from a standard penetration test under its test procedure.
In practice: The engineer reviews corrected N-values when evaluating soil behavior.
Raw, corrected, and normalized values are not interchangeable.
FHWA ↗
N/A — Not applicable
Drawings & specifications · Drawing abbreviation · Industry-wide — A marker showing that a listed requirement or field does not apply in the stated context.
In practice: The schedule marks the unused finish field N/A.
A blank field and an explicit N/A can carry different meanings.
U.S. Department of Veterans Affairs ↗
NAC — Notification appliance circuit
Electrical & fire protection · Acronym or initialism · Industry-wide — A circuit supplying or controlling fire-alarm notification appliances.
In practice: The FA contractor checks NAC loading for horns and strobes.
NFPA ↗
NAVD 88 — North American Vertical Datum of 1988
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A vertical reference datum appearing on many U.S. survey and construction documents.
In practice: The plans state that elevations are referenced to NAVD 88.
Check the project datum and transformation requirements; never mix datums casually.
NOAA / NGS ↗
NCR — Nonconformance report
Quality & inspection · Acronym or initialism · Industry-wide — A record identifying work or material that does not meet a stated requirement.
In practice: The inspector issues an NCR for an unapproved substitution.
Disposition requires the authority identified in the quality process.
AISC ↗
NDE — Nondestructive examination
Quality & inspection · Acronym or initialism · Industry-wide — Examination of material or work using methods that do not destroy its intended usefulness.
In practice: The specification identifies required NDE of selected welds.
Often used alongside NDT; the governing specification controls terminology.
American Welding Society ↗
NDS — National Design Specification for Wood Construction
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An American Wood Council design standard for wood members and connections.
In practice: The structural notes identify the applicable NDS edition.
APA – The Engineered Wood Association ↗
NDT — Nondestructive testing
Quality & inspection · Acronym or initialism · Industry-wide — Testing used to evaluate material or work without destroying its intended usefulness.
In practice: The weld inspection plan specifies NDT methods and acceptance criteria.
Method suitability and personnel qualification depend on the application.
American Welding Society ↗
NEC — National Electrical Code
Electrical & fire protection · Acronym or initialism · Industry-wide — NFPA 70, the model electrical installation code widely adopted in U.S. jurisdictions.
In practice: The electrical notes identify the adopted NEC edition and amendments.
Publication of a new edition does not automatically make it the locally enforced edition.
NFPA ↗
NECA — National Electrical Contractors Association
Project team & organizations · Organization · U.S. specific — A trade association representing electrical contractors and publishing installation resources.
In practice: The electrical contractor uses NECA training materials.
NECA ↗
NFPA — National Fire Protection Association
Project team & organizations · Organization · U.S. specific — An organization developing fire, electrical, and life-safety codes and standards.
In practice: The electrical notes identify the relevant NFPA document.
NFPA ↗
NIBS — National Institute of Building Sciences
Project team & organizations · Organization · U.S. specific — A U.S. organization supporting building science and information resources.
In practice: The team consults NIBS resources for building coordination.
GSA ↗
NIC — Not in contract
Drawings & specifications · Drawing abbreviation · Industry-wide — An indication that an item falls outside the identified contract scope.
In practice: The equipment schedule labels loose furnishings NIC.
Confirm whose contract is being referenced.
U.S. Department of Veterans Affairs ↗
NIOSH — National Institute for Occupational Safety and Health
Project team & organizations · Organization · U.S. specific — The federal institute conducting occupational safety and health research within CDC.
In practice: The industrial hygienist checks NIOSH technical guidance.
NIOSH / CDC ↗
NOI — Notice of intent
Environment & sustainability · Acronym or initialism · Industry-wide — A formal notice requesting coverage or initiating a process under the relevant program.
In practice: The construction operator submits an NOI for general-permit coverage.
Submission and authorization timing depend on the actual permit.
U.S. EPA ↗
NOT — Notice of termination
Environment & sustainability · Acronym or initialism · Industry-wide — A notice ending permit coverage when applicable conditions are satisfied.
In practice: The operator evaluates stabilization requirements before filing the NOT.
Do not assume project completion automatically terminates permit duties.
U.S. EPA ↗
NPDES — National Pollutant Discharge Elimination System
Environment & sustainability · Acronym or initialism · Industry-wide — The U.S. water-pollution permitting program for covered point-source discharges.
In practice: The operator determines the applicable NPDES construction permit authority.
U.S. EPA ↗
NRC — Noise reduction coefficient
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A single-number rating summarizing sound absorption at selected frequencies.
In practice: The ceiling schedule lists the ACT panel's NRC.
Absorption is different from blocking sound through a wall.
ASHRAE ↗
NTE — Not to exceed
Project delivery & contracts · Acronym or initialism · Industry-wide — A stated spending or authorization limit for a defined item or scope.
In practice: The owner authorizes investigation up to an NTE amount.
Clarify included costs and what approval is needed to exceed the limit.
Acquisition.gov ↗
NTP — Notice to proceed
Project delivery & contracts · Acronym or initialism · Industry-wide — A formal instruction establishing permission or a contractual date to begin specified work.
In practice: The owner issues the NTP after required prerequisites are complete.
Acquisition.gov ↗
NTS — Not to scale
Drawings & specifications · Drawing abbreviation · Industry-wide — A warning that a view is schematic or not drawn to a usable measurement scale.
In practice: The wiring diagram is labeled NTS.
Use stated dimensions and clarification; do not measure the graphic to infer size.
U.S. Department of Veterans Affairs ↗
O&M — Operations and maintenance
Design phases & commissioning · Acronym or initialism · Industry-wide — The information and activities needed to operate, inspect, and maintain an asset.
In practice: The closeout package includes O&M manuals and training records.
Operation and maintenance is another common expansion.
WBDG / NIBS ↗
OA — Outdoor air
Mechanical & HVAC · Acronym or initialism · Industry-wide — Air drawn from outside the building for ventilation or other system purposes.
In practice: The sequence specifies minimum OA flow.
OA may appear as outside air in project legends.
ASHRAE ↗
OAC — Owner-architect-contractor
Project team & organizations · Acronym or initialism · Industry-wide — The core parties in a common project coordination meeting format.
In practice: The OAC meeting reviews decisions, schedule, and pending changes.
AIA Contract Documents ↗
OC — On center
Drawings & specifications · Drawing abbreviation · Industry-wide — Spacing measured between corresponding centerlines of repeated elements.
In practice: Studs are shown at 16 inches OC.
Verify the specified spacing and exceptions around openings.
U.S. Department of Veterans Affairs ↗
OCIP — Owner-controlled insurance program
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A project insurance arrangement sponsored by the owner for defined enrolled parties and coverage.
In practice: The contractor reviews OCIP enrollment and excluded activities.
Covered parties, work, periods, exclusions, and deductibles follow the program documents.
AIA Contract Documents ↗
OFCI — Owner furnished, contractor installed
Project delivery & contracts · Acronym or initialism · Industry-wide — A responsibility split where the owner supplies an item and the contractor installs it.
In practice: The schedule identifies OFCI imaging equipment delivery dates.
Confirm unloading, storage, testing, and warranty responsibilities.
U.S. Department of Veterans Affairs ↗
OFOI — Owner furnished, owner installed
Project delivery & contracts · Acronym or initialism · Industry-wide — A responsibility split where the owner supplies and installs an item.
In practice: The drawing notes OFOI furniture in the reception area.
U.S. Department of Veterans Affairs ↗
OJT — On-the-job training
Workforce, payroll & insurance · Acronym or initialism · Industry-wide — Training delivered through supervised work activities.
In practice: The apprentice's OJT record tracks qualifying work experience.
OJT is not a substitute for required task-specific certification.
TimeTrex ↗
OMC — Optimum moisture content
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The moisture content associated with maximum dry density under a specified compaction test.
In practice: The crew conditions the fill near the specified OMC before compaction.
FHWA ↗
OPP — Opposite
Drawings & specifications · Drawing abbreviation · Industry-wide — A direction or instruction applying a detail to an opposite side or hand.
In practice: The detail note says OPP hand at the second entrance.
U.S. Department of Veterans Affairs ↗
OPR — Owner's project requirements
Design phases & commissioning · Acronym or initialism · Industry-wide — A document expressing the owner's functional needs, performance expectations, and success criteria.
In practice: The owner updates the OPR when occupancy requirements change.
Keep accepted revisions aligned with design and testing.
WBDG / NIBS ↗
OS&Y — Outside screw and yoke
Electrical & fire protection · Acronym or initialism · Industry-wide — A valve construction with the stem threads outside the valve body and a visible stem position.
In practice: The sprinkler riser detail identifies an OS&Y valve.
Confirm the valve's listing and intended system use.
NFPA ↗
OSB — Oriented strand board
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A wood structural panel made from bonded strands arranged in oriented layers.
In practice: The sheathing schedule specifies OSB thickness and fastening.
APA – The Engineered Wood Association ↗
OSHA — Occupational Safety and Health Administration
Project team & organizations · Organization · U.S. specific — The federal workplace safety and health agency within the U.S. Department of Labor.
In practice: The safety manager consults OSHA construction requirements.
OSHA ↗
OT — Overtime
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — Work time or premium pay treated as overtime under applicable law, agreement, or employer policy.
In practice: The payroll reviewer checks OT across job-coded time entries.
Job changes do not automatically restart an employee's workweek for overtime purposes.
U.S. Department of Labor ↗
PAPR — Powered air-purifying respirator
Safety & occupational health · Acronym or initialism · Industry-wide — A respirator that uses a powered blower to move air through filtering components.
In practice: The respiratory program identifies the appropriate PAPR configuration.
Filter, atmosphere, fit, and program requirements depend on the equipment and exposure.
OSHA ↗
PC — Precast concrete
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete cast away from its final installed position and moved into place after gaining sufficient strength.
In practice: The crane plan includes erection of PC wall panels.
PC has many meanings; confirm the structural legend.
American Concrete Institute ↗
PCC — Portland cement concrete
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Concrete made with portland cement or a specified blended cementitious system, commonly distinguished from asphalt paving.
In practice: The roadway details show PCC pavement at the intersection.
FHWA ↗
PCO — Potential change order
Project delivery & contracts · Acronym or initialism · Industry-wide — A proposed or anticipated contract change tracked before final approval.
In practice: The team logs a PCO while the subcontractor prices revised footings.
Some project systems expand PCO as proposed change order.
AIA Contract Documents ↗
PDM — Precedence diagramming method
Estimating & project controls · Acronym or initialism · Industry-wide — A schedule network approach linking activities through defined dependency relationships.
In practice: The schedule uses PDM relationships between trade activities.
FHWA ↗
PE — Project engineer
Project team & organizations · Acronym or initialism · Industry-wide — A project staff role supporting coordination, submittals, RFIs, and field documentation.
In practice: The contractor's PE maintains the submittal log.
This job title does not establish professional engineering licensure.
AIA Contract Documents ↗
PE — Professional engineer
Project team & organizations · Acronym or initialism · Industry-wide — A person licensed to practice engineering by a U.S. licensing jurisdiction.
In practice: A PE seals documents where required for the assigned discipline.
License status, discipline, and permitted services must be checked with the relevant board.
Acquisition.gov ↗
PEL — Permissible exposure limit
Safety & occupational health · Acronym or initialism · Industry-wide — An enforceable occupational exposure limit under the applicable OSHA provision.
In practice: The exposure assessment compares results with the relevant PEL.
The substance, averaging period, jurisdiction, and applicable rule matter.
NIOSH / CDC ↗
PEX — Cross-linked polyethylene
Plumbing & utilities · Acronym or initialism · Industry-wide — A polymer piping material used in water distribution and other approved applications.
In practice: The water distribution detail specifies PEX connections.
Use compatible listed fittings and the specified installation method.
ASHRAE ↗
PFAS — Personal fall arrest system
Safety & occupational health · Acronym or initialism · Industry-wide — A connected system designed to arrest a worker's fall under specified conditions.
In practice: The fall-protection plan identifies compatible PFAS components and rescue arrangements.
In environmental documents PFAS refers to a family of chemicals, not fall protection.
OSHA ↗
PFAS — Per- and polyfluoroalkyl substances
Environment & sustainability · Acronym or initialism · Industry-wide — A broad group of manufactured fluorinated chemicals relevant to some environmental and material assessments.
In practice: The remediation report evaluates PFAS in sampled water.
In construction safety, PFAS means personal fall arrest system; the meanings are unrelated.
U.S. EPA ↗
PFC — Prefunctional checklist
Design phases & commissioning · Acronym or initialism · Industry-wide — A checklist recording installation and readiness conditions before functional testing.
In practice: The installer completes the PFC before the witnessed test.
Project terminology may call these construction checklists.
WBDG / NIBS ↗
PI — Plasticity index
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The difference between a soil's liquid limit and plastic limit.
In practice: The earthwork specification sets a PI criterion for imported fill.
Test results describe material behavior; acceptance follows the project specification.
FHWA ↗
PIV — Post indicator valve
Electrical & fire protection · Acronym or initialism · Industry-wide — A valve assembly with a visible indication of valve position, commonly used on fire-protection mains.
In practice: The utility plan identifies the PIV outside the building.
NFPA ↗
PJP — Partial joint penetration
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A groove weld condition with penetration limited to the specified portion of joint thickness.
In practice: The shop drawing identifies the required PJP weld size.
AISC ↗
PL — Plastic limit
Civil, survey & earthwork · Acronym or initialism · Industry-wide — The moisture content at a defined boundary between semisolid and plastic soil behavior.
In practice: The laboratory measures PL for the soil classification.
FHWA ↗
PLA — Project labor agreement
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A pre-hire collective bargaining agreement setting terms for work on a specified construction project.
In practice: The contractor reviews the project's PLA before planning labor deployment.
Applicability and terms are project-specific.
Acquisition.gov ↗
PM — Project manager
Project team & organizations · Acronym or initialism · Industry-wide — The person coordinating project scope, schedule, budget, and communication for an organization.
In practice: The PM tracks unresolved decisions before the next milestone.
The same title can represent the owner, designer, or contractor.
AIA Contract Documents ↗
PO — Purchase order
Project delivery & contracts · Acronym or initialism · Industry-wide — A purchasing document identifying ordered goods or services and commercial terms.
In practice: The buyer issues a PO for specified pumps.
Acquisition.gov ↗
PPC — Percent plan complete
Estimating & project controls · Acronym or initialism · Industry-wide — A Lean planning measure of commitments completed as promised during a defined planning period.
In practice: The weekly review measures PPC and discusses reasons for variance.
Use a consistent definition of a completed commitment.
Lean Construction Institute ↗
PPE — Personal protective equipment
Safety & occupational health · Acronym or initialism · Industry-wide — Equipment worn to reduce exposure to specific workplace hazards.
In practice: The JHA identifies task-appropriate PPE before work starts.
PPE selection is one part of hazard control, not a complete safety plan.
OSHA ↗
PQR — Procedure qualification record
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A record of welding variables and test results supporting procedure qualification.
In practice: The fabricator submits a PQR supporting the proposed WPS.
American Welding Society ↗
PR — Proposal request
Project delivery & contracts · Acronym or initialism · Industry-wide — A request to price a possible change so the owner can assess its effects.
In practice: The architect issues a PR for upgraded doors.
A proposal request generally seeks pricing; check whether separate authorization is needed to proceed.
AIA Contract Documents ↗
PRCS — Permit-required confined space
Safety & occupational health · Acronym or initialism · Industry-wide — A confined space with one or more specified hazards triggering permit-space requirements.
In practice: The entry assessment determines whether the space is a PRCS.
Do not determine entry safety from the acronym alone.
OSHA ↗
PS — Prestressed concrete
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete in which intentional compressive stresses counteract some effects of applied loading.
In practice: The bridge uses PS girders fabricated off site.
Prestressing includes pretensioning and post-tensioning approaches.
American Concrete Institute ↗
psi — Pounds per square inch
Units & measurements · Unit or symbol · Industry-wide — A U.S. customary pressure or stress unit.
In practice: The concrete schedule states strength in psi.
Distinguish pressure from strength and specify gauge or absolute pressure where relevant.
NIST ↗
PSL — Parallel strand lumber
Structural steel, wood & welding · Acronym or initialism · Industry-wide — Structural composite lumber made from long wood strands bonded mainly parallel to the member length.
In practice: The design specifies PSL posts.
APA – The Engineered Wood Association ↗
PT — Post-tensioning
Concrete & masonry · Acronym or initialism · Industry-wide — A prestressing method that tensions tendons after concrete has gained specified strength.
In practice: The slab sequence includes PT stressing and inspection.
Do not cut, drill, or alter tendons based on a glossary explanation.
American Concrete Institute ↗
PT — Penetrant testing
Quality & inspection · Acronym or initialism · Industry-wide — A nondestructive method using liquid penetrant to reveal surface-breaking discontinuities in suitable materials.
In practice: The inspector performs PT on the specified component.
PT means post-tensioning in concrete work.
American Welding Society ↗
PV — Photovoltaic
Electrical & fire protection · Acronym or initialism · Industry-wide — Technology that converts light into electrical energy.
In practice: The roof plan coordinates PV arrays with access paths.
ASHRAE ↗
PV — Planned value
Estimating & project controls · Acronym or initialism · Industry-wide — The budgeted value of work scheduled to be performed by a specified date.
In practice: The controls report compares PV with EV at the data date.
PV in electrical design usually means photovoltaic.
U.S. Department of Energy ↗
PVC — Polyvinyl chloride
Plumbing & utilities · Acronym or initialism · Industry-wide — A thermoplastic used in pipes, conduit, membranes, and other building products.
In practice: The plumbing specification identifies permitted PVC pipe applications.
PVC pipe, conduit, and roofing products are not interchangeable.
ASHRAE ↗
QA — Quality assurance
Quality & inspection · Acronym or initialism · Industry-wide — Planned activities providing confidence that requirements will be met.
In practice: The owner defines QA oversight for the construction process.
QA and QC responsibilities should be explicit in the quality plan.
AISC ↗
QA/QC — Quality assurance and quality control
Quality & inspection · Acronym or initialism · Industry-wide — The combined planning, oversight, testing, and checking processes supporting conformance.
In practice: The project QA/QC plan defines inspection responsibilities and records.
The combined label does not erase the distinction between the two functions.
AISC ↗
QC — Quality control
Quality & inspection · Acronym or initialism · Industry-wide — Operational checks and activities used to verify that work meets requirements.
In practice: The contractor's QC team checks the installation before inspection.
AISC ↗
QL — Quality level
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A classification describing the reliability and collection basis of subsurface utility information.
In practice: The utility plan distinguishes QL B mapping from QL A exposure data.
The applicable SUE standard defines each level.
FHWA ↗
QTO — Quantity takeoff
Estimating & project controls · Acronym or initialism · Industry-wide — Measurement or counting of work quantities from project information.
In practice: The estimator checks the concrete QTO against slab dimensions.
Model quantities still require scope and measurement-rule review.
Acquisition.gov ↗
R-value — Thermal resistance
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A measure of resistance to heat flow through a material or assembly under stated conditions.
In practice: The wall schedule distinguishes cavity insulation R-value from whole-wall performance.
U.S. and SI R-values have different numeric scales.
U.S. Department of Energy ↗
RA — Return air
Mechanical & HVAC · Acronym or initialism · Industry-wide — Air drawn from a conditioned space back toward the air-handling system.
In practice: The corridor ceiling contains the RA grille.
ASHRAE ↗
RAP — Reclaimed asphalt pavement
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Recovered asphalt pavement material processed for reuse.
In practice: The mix design lists the permitted RAP content.
FHWA ↗
RC — Reinforced concrete
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete containing reinforcement intended to act together under applied loads.
In practice: The section shows an RC foundation wall.
American Concrete Institute ↗
RCC — Roller-compacted concrete
Concrete & masonry · Acronym or initialism · Industry-wide — A stiff concrete mixture placed and compacted using earthmoving and roller equipment.
In practice: The pavement contractor places RCC in planned lifts.
It differs from conventional slump concrete and normal asphalt paving.
American Concrete Institute ↗
RCP — Reflected ceiling plan
Drawings & specifications · Drawing abbreviation · Industry-wide — A plan view showing ceiling layout, heights, finishes, and coordinated devices.
In practice: The RCP locates lights relative to ceiling tiles.
On utility plans, RCP commonly means reinforced concrete pipe.
U.S. Department of Veterans Affairs ↗
RCP — Reinforced concrete pipe
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Concrete pipe containing reinforcement for the intended structural and service conditions.
In practice: The drainage plan specifies RCP beneath the road.
RCP means reflected ceiling plan in architectural coordination.
FHWA ↗
RCS — Respirable crystalline silica
Safety & occupational health · Acronym or initialism · Industry-wide — Airborne crystalline silica particles small enough to reach deep into the lungs.
In practice: The task assessment addresses RCS during concrete cutting.
OSHA ↗
RCx — Retro-commissioning
Design phases & commissioning · Acronym or initialism · Industry-wide — Commissioning applied to an existing building or system that was not previously commissioned under the intended process.
In practice: The owner uses RCx to investigate existing operating problems.
Recommissioning is a related term for repeating commissioning; scope definitions vary.
WBDG / NIBS ↗
REL — Recommended exposure limit
Safety & occupational health · Acronym or initialism · Industry-wide — A NIOSH-recommended occupational exposure limit.
In practice: The industrial hygienist reviews the NIOSH REL with applicable legal limits.
A recommendation is not automatically an enforceable limit.
NIOSH / CDC ↗
RFI — Request for information
Project delivery & contracts · Acronym or initialism · Industry-wide — A documented question used to clarify drawings, specifications, or other project information.
In practice: The GC sends an RFI about a conflict between the beam and duct layouts.
An RFI response does not itself authorize added cost or time; follow the contract change process.
AIA Contract Documents ↗
RFP — Request for proposals
Project delivery & contracts · Acronym or initialism · Industry-wide — A solicitation asking respondents to propose an approach, qualifications, and often price.
In practice: The owner issues an RFP for a design-build team.
Acquisition.gov ↗
RFQ — Request for qualifications
Project delivery & contracts · Acronym or initialism · Industry-wide — A solicitation focused on a firm's experience, personnel, and ability to perform.
In practice: An RFQ shortlists firms before the owner requests detailed proposals.
In purchasing, RFQ can instead mean request for quotation.
Acquisition.gov ↗
RFQ — Request for quotation
Project delivery & contracts · Acronym or initialism · Industry-wide — A purchasing request for pricing and supply terms on defined goods or services.
In practice: The estimator sends an RFQ to three switchgear suppliers.
Distinguish a price quotation from a qualifications submission.
Acquisition.gov ↗
RMC — Rigid metal conduit
Electrical & fire protection · Acronym or initialism · Industry-wide — A robust threaded metal raceway used for conductor protection in specified locations.
In practice: The service installation uses RMC where detailed.
ASHRAE ↗
RO — Rough opening
Drawings & specifications · Drawing abbreviation · Industry-wide — The framed or unfinished opening sized to receive a door, window, or other assembly.
In practice: The framer checks the RO against the window schedule.
U.S. Department of Veterans Affairs ↗
ROM — Rough order of magnitude
Estimating & project controls · Acronym or initialism · Industry-wide — An early estimate used for planning when project definition is limited.
In practice: The owner requests a ROM budget before selecting a concept.
A ROM estimate is not a firm bid; state scope, assumptions, and uncertainty.
Acquisition.gov ↗
ROPS — Rollover protective structure
Safety & occupational health · Acronym or initialism · Industry-wide — A protective structure intended to reduce crushing hazards during equipment rollover under its design conditions.
In practice: The equipment inspection checks the ROPS and restraint system.
Protection depends on the equipment design and proper use.
OSHA ↗
ROW — Right-of-way
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Land or legal rights designated for a road, utility, or other corridor purpose.
In practice: The utility alignment remains within the indicated ROW.
Confirm the legal boundaries and permitted rights, not just the graphic line.
FHWA ↗
RPZ — Reduced pressure zone assembly
Plumbing & utilities · Acronym or initialism · Industry-wide — Common terminology for a backflow prevention assembly using a reduced-pressure zone and relief arrangement.
In practice: The domestic water service includes the specified RPZ assembly.
Some standards prefer reduced pressure principle assembly; verify approved device terminology.
International Code Council ↗
RTK — Real-time kinematic
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A GNSS survey technique using correction data for precise positioning in real time.
In practice: The surveyor checks RTK results against site control.
Accuracy depends on equipment, corrections, conditions, and verification.
NOAA / NGS ↗
RTU — Rooftop unit
Mechanical & HVAC · Acronym or initialism · Industry-wide — Packaged mechanical equipment located on a roof, commonly for heating and cooling.
In practice: The crane plan coordinates RTU placement with curb installation.
ASHRAE ↗
SA — Supply air
Mechanical & HVAC · Acronym or initialism · Industry-wide — Air delivered by a system to a space or process.
In practice: The plan shows SA diffusers along the perimeter.
ASHRAE ↗
SBS — Styrene-butadiene-styrene
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A polymer used to modify bitumen for roofing and waterproofing products.
In practice: The roofing submittal identifies an SBS-modified sheet.
NRCA ↗
SCBA — Self-contained breathing apparatus
Safety & occupational health · Acronym or initialism · Industry-wide — Respiratory equipment carrying its own supply of breathing air.
In practice: The trained response team checks the specified SCBA equipment.
Its use requires appropriate training and procedures.
OSHA ↗
SCC — Self-consolidating concrete
Concrete & masonry · Acronym or initialism · Industry-wide — Concrete proportioned to flow into place and around reinforcement with little or no mechanical consolidation.
In practice: The precaster submits an SCC mixture for congested panels.
Fresh-property tests and placement limits must follow the approved procedure.
American Concrete Institute ↗
SCCR — Short-circuit current rating
Electrical & fire protection · Acronym or initialism · Industry-wide — The specified maximum prospective short-circuit current an assembly or component can withstand under stated conditions.
In practice: The engineer compares equipment SCCR with available fault current.
SCCR is distinct from an interrupting rating.
OSHA ↗
SCM — Supplementary cementitious material
Concrete & masonry · Acronym or initialism · Industry-wide — A material used with cement to contribute to concrete properties through hydraulic or pozzolanic activity.
In practice: The mix submittal identifies the SCM content.
Common examples include slag cement and fly ash; performance depends on the mixture.
American Concrete Institute ↗
SD — Schematic design
Design phases & commissioning · Acronym or initialism · Industry-wide — An early design phase developing the concept, major relationships, and initial systems approach.
In practice: The owner reviews the SD concept before further design development.
SD in fire-protection drawings may mean smoke detector or smoke damper.
AIA Contract Documents ↗
SDS — Safety data sheet
Safety & occupational health · Acronym or initialism · Industry-wide — A standardized document describing a chemical product's hazards and handling information.
In practice: The supervisor checks the SDS before approving a new adhesive.
Use the sheet for the actual product and current formulation.
OSHA ↗
SE — Structural engineer
Project team & organizations · Acronym or initialism · Industry-wide — An engineer working in structural engineering; in some U.S. jurisdictions, SE is also a separately regulated license or title.
In practice: The team checks the SE's authority for the project jurisdiction.
A job title or acronym alone does not prove a current professional license.
AISC ↗
SEC — Section
Drawings & specifications · Drawing abbreviation · Industry-wide — A cut-through view showing the relationship of components in depth or height.
In practice: The wall SEC shows flashing behind the cladding.
U.S. Department of Veterans Affairs ↗
SER — Structural engineer of record
Project team & organizations · Acronym or initialism · Industry-wide — The professional responsible for the project's structural design within the agreed scope.
In practice: The SER reviews a proposed framing revision.
AISC ↗
SF — Start-to-finish
Estimating & project controls · Acronym or initialism · Industry-wide — A dependency relating the successor's finish to the predecessor's start with any stated lag.
In practice: A handover model uses SF where one coverage period cannot end before another begins.
This uncommon dependency should be used deliberately and checked carefully.
FHWA ↗
SF — Square foot
Units & measurements · Unit or symbol · Industry-wide — A U.S. customary unit of area equal to 144 square inches.
In practice: The estimate measures flooring in SF.
SF in scheduling means start-to-finish.
NIST ↗
SHGC — Solar heat gain coefficient
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — The fraction of incident solar radiation entering through a glazing or fenestration assembly as heat.
In practice: The window selection meets the specified SHGC.
Compare values for the same rated product scope.
U.S. Department of Energy ↗
SIM — Similar
Drawings & specifications · Drawing abbreviation · Industry-wide — A drawing reference to a comparable detail that may require identified adjustments.
In practice: A SIM detail applies to the opposite end of the wall.
Similar does not necessarily mean identical.
U.S. Department of Veterans Affairs ↗
SLC — Signaling line circuit
Electrical & fire protection · Acronym or initialism · Industry-wide — A fire-alarm circuit communicating data among addressable devices and control equipment.
In practice: The fire-alarm riser shows the SLC device loop.
NFPA ↗
SMACNA — Sheet Metal and Air Conditioning Contractors' National Association
Project team & organizations · Organization · U.S. specific — A trade association producing technical standards used for sheet metal and duct construction.
In practice: The duct specification references a SMACNA construction standard.
ASHRAE ↗
SMAW — Shielded metal arc welding
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An arc welding process using a flux-covered consumable electrode.
In practice: The erection WPS permits SMAW for the field connection.
Often called stick welding.
American Welding Society ↗
SOG — Slab on grade
Concrete & masonry · Acronym or initialism · Industry-wide — A slab supported by the prepared ground or subbase beneath it.
In practice: The SOG detail includes vapor control and joint locations.
A slab on grade is not necessarily part of the structural foundation system.
American Concrete Institute ↗
SOQ — Statement of qualifications
Project delivery & contracts · Acronym or initialism · Industry-wide — A submission describing a team's relevant experience, credentials, and capacity.
In practice: The architect includes similar completed projects in its SOQ.
Acquisition.gov ↗
SOV — Schedule of values
Estimating & project controls · Acronym or initialism · Industry-wide — A breakdown allocating the contract value among work items for payment administration.
In practice: The pay application reports progress against the SOV.
An SOV supports billing and does not necessarily equal the internal cost estimate.
AIA Contract Documents ↗
SOW — Scope of work
Project delivery & contracts · Acronym or initialism · Industry-wide — The work, deliverables, and boundaries assigned under an agreement or package.
In practice: The SOW identifies who installs roof penetrations.
SOW can also be expanded as statement of work; read the document's definition.
Acquisition.gov ↗
SPCC — Spill Prevention, Control, and Countermeasure
Environment & sustainability · Acronym or initialism · Industry-wide — An EPA oil-pollution prevention program and associated plan requirements for covered facilities.
In practice: The environmental lead checks whether site oil storage triggers SPCC requirements.
U.S. EPA ↗
SPI — Schedule performance index
Estimating & project controls · Acronym or initialism · Industry-wide — An earned-value ratio calculated as earned value divided by planned value.
In practice: The controls team reports SPI alongside critical-path analysis.
SPI does not directly state the number of days late and can mask critical-path issues.
U.S. Department of Energy ↗
SPT — Standard penetration test
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A geotechnical field test recording penetration resistance during soil sampling.
In practice: The geotechnical report provides SPT results by depth.
FHWA ↗
SRL — Self-retracting lifeline
Safety & occupational health · Acronym or initialism · Industry-wide — A fall-protection device that retracts line and locks under defined fall conditions.
In practice: The competent person checks the specified SRL for the intended application.
Clearance, leading-edge rating, anchorage, and rescue requirements vary by device and use.
OSHA ↗
SS — Start-to-start
Estimating & project controls · Acronym or initialism · Industry-wide — A dependency relating the successor's start to the predecessor's start with any stated lag.
In practice: The schedule uses SS to model overlapping work areas.
SS can mean stainless steel in material schedules.
FHWA ↗
SSMA — Steel Stud Manufacturers Association
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An industry association associated with cold-formed steel framing products and technical resources.
In practice: The specification references SSMA member designations.
SSMA ↗
STC — Sound transmission class
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A single-number rating of airborne sound isolation derived from standardized testing.
In practice: The partition schedule specifies an STC-rated assembly.
The installed assembly and flanking paths affect real performance.
ASHRAE ↗
STEL — Short-term exposure limit
Safety & occupational health · Acronym or initialism · Industry-wide — An exposure limit averaged over a defined short period under the relevant authority or guidance.
In practice: The hygienist checks short-duration exposure against the applicable STEL.
The source defines the duration and conditions.
NIOSH / CDC ↗
SUE — Subsurface utility engineering
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A process for managing risks associated with buried utility information using defined investigation methods.
In practice: The design team requests SUE before finalizing foundations near utilities.
FHWA ↗
SWL — Safe working load
Safety & occupational health · Acronym or initialism · Industry-wide — A stated allowable working load under defined conditions, often used in lifting documentation.
In practice: The lift plan identifies the SWL stated for the equipment.
Terminology varies; never infer a lifting capacity from the acronym alone.
OSHA ↗
SWPPP — Stormwater pollution prevention plan
Environment & sustainability · Acronym or initialism · Industry-wide — A site-specific plan identifying stormwater pollution sources and control measures under the applicable permit.
In practice: The inspector documents corrective actions required by the SWPPP.
A SWPPP is a plan, not the permit authorization itself.
U.S. EPA ↗
SY — Square yard
Units & measurements · Unit or symbol · Industry-wide — A U.S. customary unit of area equal to nine square feet.
In practice: The paving quantity is listed in SY.
Check the measured area and pay-item rules.
NIST ↗
T&A — Time and attendance
Workforce, payroll & insurance · Acronym or initialism · Industry-wide — Processes and systems recording employee work time, attendance, and related exceptions.
In practice: The supervisor approves job-coded T&A records before payroll.
Time records should reflect actual work under the applicable rules.
TimeTrex ↗
T&M — Time and materials
Project delivery & contracts · Acronym or initialism · Industry-wide — A pricing approach based on specified labor charges and material costs rather than one fixed total.
In practice: The superintendent verifies quantities on a T&M ticket.
Rates, markups, documentation, and limits come from the agreement.
Acquisition.gov ↗
TAB — Testing, adjusting, and balancing
Mechanical & HVAC · Acronym or initialism · Industry-wide — A process measuring and setting air and water system flows to meet specified requirements.
In practice: The TAB contractor records final diffuser and hydronic flow values.
TAB is one input to commissioning, not the whole commissioning process.
WBDG / NIBS ↗
TBM — Temporary benchmark
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A project reference point established for convenient elevation control.
In practice: The crew protects the TBM near the site entrance.
On tunneling projects TBM usually means tunnel boring machine.
NOAA / NGS ↗
TBM — Tunnel boring machine
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A mechanized system that excavates a tunnel and may support or line it as work advances.
In practice: The tunneling plan specifies access for TBM assembly.
FHWA ↗
TCO — Temporary certificate of occupancy
Codes & accessibility · Code, standard or program · U.S. specific — A jurisdictional authorization allowing occupancy subject to stated conditions or time limits.
In practice: The owner tracks outstanding conditions listed on the TCO.
Availability and terms depend on the issuing jurisdiction.
International Code Council ↗
TF — Total float
Estimating & project controls · Acronym or initialism · Industry-wide — The time an activity can be delayed without delaying the relevant completion date under the schedule's calculation rules.
In practice: The scheduler investigates a reduction in TF.
Float depends on logic, calendars, constraints, and the scheduling method.
FHWA ↗
TIA — Time impact analysis
Estimating & project controls · Acronym or initialism · Industry-wide — A schedule analysis evaluating how an event or change affects project timing.
In practice: The scheduler prepares a TIA for the proposed change.
The contract or agreed protocol defines the analysis method and data date.
FHWA ↗
TMP — Transportation management plan
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A coordinated plan addressing work-zone traffic control and other transportation impacts.
In practice: The project TMP includes incident response and public information.
FHWA ↗
TO — Top of
Drawings & specifications · Drawing abbreviation · Industry-wide — An elevation or position prefix identifying the upper surface of a named element.
In practice: The detail gives the TO curb elevation.
TO can be an ordinary word; capitalization matching helps the decoder.
U.S. Department of Veterans Affairs ↗
TOC — Top of concrete
Drawings & specifications · Drawing abbreviation · Industry-wide — The upper surface elevation of a named concrete element.
In practice: The footing detail gives TOC at the pedestal.
TOC can mean top of curb on civil drawings.
U.S. Department of Veterans Affairs ↗
TOC — Top of curb
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation of the upper surface of a curb.
In practice: The grading plan gives TOC at each curb return.
Read the civil legend; building sections may use top of concrete.
U.S. Department of Veterans Affairs ↗
TOPO — Topographic survey
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A survey recording ground features and elevations for planning and design.
In practice: The civil engineer uses the TOPO to develop grading.
NOAA / NGS ↗
TOS — Top of steel
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation at the top surface of the specified structural steel member.
In practice: The framing plan assigns a TOS elevation to a beam.
Some project legends use TOS for top of slab; confirm the legend.
AISC ↗
TOS — Top of slab
Drawings & specifications · Drawing abbreviation · Industry-wide — The elevation at the upper surface of the indicated slab.
In practice: The section labels the garage TOS below the finished floor.
Distinguish this from top of steel on structural plans.
U.S. Department of Veterans Affairs ↗
TPO — Thermoplastic polyolefin
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A thermoplastic single-ply roofing membrane material.
In practice: The roof specification identifies a TPO membrane system.
NRCA ↗
TRIR — Total recordable incident rate
Safety & occupational health · Acronym or initialism · Industry-wide — A safety metric commonly calculated from recordable cases and employee hours using a 200,000-hour base.
In practice: The contractor reports TRIR with its case count and hours.
Definitions, workforce scope, and reporting period must match when comparing rates.
OSHA ↗
TTC — Temporary traffic control
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Devices and arrangements guiding road users through a temporary work condition.
In practice: The TTC layout includes signs, channelizing devices, and taper geometry.
FHWA ↗
TWA — Time-weighted average
Safety & occupational health · Acronym or initialism · Industry-wide — An exposure concentration averaged over a specified period with time weighting.
In practice: The report identifies the averaging period for the TWA result.
Always state the time period; TWA alone does not specify one.
NIOSH / CDC ↗
TYP — Typical
Drawings & specifications · Drawing abbreviation · Industry-wide — A note indicating that a detail or condition applies to similar locations unless otherwise identified.
In practice: A TYP note applies to repeated guardrail connections.
Do not extend a typical detail to conditions the documents do not cover.
U.S. Department of Veterans Affairs ↗
U-factor — Thermal transmittance
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — The rate of heat transfer through an assembly per unit area and temperature difference.
In practice: The energy model uses the rated window U-factor.
Lower U-factor indicates less heat transfer under the stated rating conditions.
U.S. Department of Energy ↗
UHPC — Ultra-high-performance concrete
Concrete & masonry · Acronym or initialism · Industry-wide — A category of cementitious material with high mechanical performance and durability, often with fiber reinforcement.
In practice: The bridge joint detail specifies UHPC closure pours.
Use the project's performance definition and qualification requirements.
American Concrete Institute ↗
UNO — Unless noted otherwise
Drawings & specifications · Drawing abbreviation · Industry-wide — A qualifier stating that a general instruction applies except where specific notes override it.
In practice: The structural notes specify a default cover UNO.
Resolve conflicting notes through the document hierarchy and clarification process.
U.S. Department of Veterans Affairs ↗
UON — Unless otherwise noted
Drawings & specifications · Drawing abbreviation · Industry-wide — A qualifier that allows a specific note to override a general instruction.
In practice: The drawing gives typical anchor spacing UON.
Equivalent wording is often abbreviated UNO.
U.S. Department of Veterans Affairs ↗
UPS — Uninterruptible power supply
Electrical & fire protection · Acronym or initialism · Industry-wide — Equipment providing continuity of power for a defined load during supply disturbances or interruptions.
In practice: The controls server is connected to a UPS.
Runtime and supported load depend on system design and battery condition.
ASHRAE ↗
USACE — U.S. Army Corps of Engineers
Project team & organizations · Organization · U.S. specific — A federal agency involved in military facilities, civil works, and other engineering missions.
In practice: The contractor checks the USACE project's contract requirements.
Acquisition.gov ↗
USCS — Unified Soil Classification System
Civil, survey & earthwork · Acronym or initialism · Industry-wide — A system grouping soils using particle size and plasticity characteristics.
In practice: The boring log classifies the material as CL under USCS.
FHWA ↗
USGBC — U.S. Green Building Council
Environment & sustainability · Acronym or initialism · Industry-wide — The organization associated with developing the LEED green building rating system.
In practice: The team checks USGBC resources for the selected rating system.
U.S. Green Building Council ↗
UT — Ultrasonic testing
Quality & inspection · Acronym or initialism · Industry-wide — A nondestructive method using high-frequency sound to examine material or welds.
In practice: The inspector performs UT where required by the weld inspection plan.
American Welding Society ↗
VAV — Variable air volume
Mechanical & HVAC · Acronym or initialism · Industry-wide — An air-distribution approach that varies airflow to meet zone requirements.
In practice: The controls sequence adjusts the VAV terminal airflow.
ASHRAE ↗
VCT — Vinyl composition tile
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A resilient floor tile product containing vinyl binder and mineral fillers.
In practice: The finish schedule assigns VCT to the storage room.
U.S. Department of Veterans Affairs ↗
VDC — Virtual design and construction
BIM & digital coordination · Acronym or initialism · Industry-wide — The use of integrated digital models and planning methods to improve project delivery.
In practice: The VDC team combines coordination models with installation planning.
GSA ↗
VE — Value engineering
Estimating & project controls · Acronym or initialism · Industry-wide — A structured review seeking required functions and performance at an appropriate life-cycle cost.
In practice: The team evaluates a VE alternative while preserving required durability.
A lower first cost alone does not establish equal value or performance.
Acquisition.gov ↗
VFD — Variable frequency drive
Mechanical & HVAC · Acronym or initialism · Industry-wide — An electronic drive controlling an AC motor by varying supply frequency and related electrical output.
In practice: The fan's VFD modulates speed under the controls sequence.
Electrical installation and motor compatibility remain separate design checks.
ASHRAE ↗
VIF — Verify in field
Drawings & specifications · Drawing abbreviation · Industry-wide — An instruction to confirm an actual site dimension or condition before proceeding.
In practice: The installer must VIF the opening before ordering the frame.
Field verification does not authorize changing design requirements.
U.S. Department of Veterans Affairs ↗
VOC — Volatile organic compound
Environment & sustainability · Acronym or initialism · Industry-wide — An organic compound with volatility characteristics defined by the relevant air-quality or product program.
In practice: The finish specification sets a VOC criterion for adhesive.
VOC content and product emissions are different measures.
U.S. EPA ↗
VRF — Variable refrigerant flow
Mechanical & HVAC · Acronym or initialism · Industry-wide — A refrigerant-based system that varies refrigerant flow to multiple indoor units.
In practice: The VRF submittal identifies connected indoor-unit capacities.
ASHRAE ↗
VTR — Vent through roof
Plumbing & utilities · Acronym or initialism · Industry-wide — A plumbing vent termination extending through the roof.
In practice: The roof plan coordinates the VTR with flashing and clearances.
ASHRAE ↗
W — Wide-flange shape
Structural steel, wood & welding · Acronym or initialism · Industry-wide — An AISC steel shape designation for a wide-flange beam or column.
In practice: The framing schedule lists a W shape by depth and weight.
A single letter is omitted from passage decoding to reduce ordinary-word matches.
AISC ↗
w/c — Water-cement ratio
Concrete & masonry · Unit or symbol · Industry-wide — The mass of water divided by the mass of cement in a concrete mixture.
In practice: The laboratory distinguishes w/c from w/cm on the mix report.
Confirm which binder components the specification includes.
American Concrete Institute ↗
w/cm — Water-cementitious materials ratio
Concrete & masonry · Unit or symbol · Industry-wide — The mass of water divided by the mass of cementitious materials in a concrete mixture.
In practice: The specification limits w/cm for the exposure condition.
This differs from water-cement ratio when supplementary materials are present.
American Concrete Institute ↗
WBDG — Whole Building Design Guide
Project team & organizations · Organization · U.S. specific — A building design and delivery reference resource associated with NIBS.
In practice: The commissioning lead reviews WBDG guidance on project requirements.
WBDG / NIBS ↗
WBS — Work breakdown structure
Estimating & project controls · Acronym or initialism · Industry-wide — A hierarchical organization of project work into manageable elements.
In practice: The estimate and schedule align to the WBS.
Keep the work scope and coding rules consistent across systems.
Acquisition.gov ↗
WC — Workers' compensation
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — The insurance and legal system addressing covered work-related injury or illness benefits.
In practice: The contractor provides required WC coverage documentation.
State requirements and policy terms vary.
OSHA ↗
WD — Wage determination
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — A document identifying applicable wage and fringe benefit rates and classifications under a prevailing wage program.
In practice: The payroll specialist uses the WD incorporated into the contract.
Check the correct determination, modification, and contract terms.
U.S. Department of Labor ↗
WH-347 — Weekly certified payroll form
Workforce, payroll & insurance · Acronym or initialism · U.S. specific — An optional DOL form used to report payroll for covered Davis-Bacon and Related Acts construction work.
In practice: The contractor completes WH-347 or an acceptable equivalent submission.
The form is optional; required payroll reporting and certification for covered work are not optional.
U.S. Department of Labor ↗
WHD — Wage and Hour Division
Project team & organizations · Organization · U.S. specific — The DOL division administering federal wage laws and certain government-contract labor standards.
In practice: The contractor reviews WHD certified payroll instructions.
U.S. Department of Labor ↗
WIP — Work in progress
Estimating & project controls · Acronym or initialism · Industry-wide — Work or contract activity not yet complete, often summarized in construction accounting reports.
In practice: The monthly WIP report reconciles cost, billing, and projected completion.
Accounting methods and report definitions must be stated.
Acquisition.gov ↗
WLL — Working load limit
Safety & occupational health · Acronym or initialism · Industry-wide — The maximum working load assigned to a lifting component for specified conditions of use.
In practice: The rigger checks the sling WLL for the intended configuration.
Angles, configuration, condition, and manufacturer limits affect suitability.
OSHA ↗
WMA — Warm-mix asphalt
Civil, survey & earthwork · Acronym or initialism · Industry-wide — Asphalt mixture produced with technologies allowing lower production or placement temperatures than comparable HMA.
In practice: The contractor submits a WMA mix design for review.
WMA is a technology category rather than one fixed temperature.
FHWA ↗
WPQ — Welder performance qualification
Structural steel, wood & welding · Acronym or initialism · Industry-wide — Documentation or testing demonstrating a welder's ability within a qualified range.
In practice: The inspector verifies WPQ coverage for the work.
Qualification range and continuity requirements depend on the governing code.
American Welding Society ↗
WPS — Welding procedure specification
Structural steel, wood & welding · Acronym or initialism · Industry-wide — A document specifying the variables and instructions for making a qualified weld.
In practice: The welder follows the approved WPS for the connection.
American Welding Society ↗
WRB — Water-resistive barrier
Envelope, roofing & finishes · Acronym or initialism · Industry-wide — A layer intended to resist liquid water penetration behind exterior cladding.
In practice: The installer integrates window flashing with the WRB.
Water resistance, air control, and vapor control are distinct functions.
ASHRAE ↗
WSFU — Water supply fixture unit
Plumbing & utilities · Acronym or initialism · Industry-wide — A relative water-supply demand unit used in plumbing sizing methods.
In practice: The plumbing calculation totals WSFU for the fixture group.
International Code Council ↗
WWF — Welded wire fabric
Concrete & masonry · Legacy terminology · Industry-wide — A legacy term commonly used for welded wire reinforcement.
In practice: An older drawing calls the slab mesh WWF.
Current documents often prefer WWR; verify wire sizes and spacing.
American Concrete Institute ↗
WWP — Weekly work plan
Estimating & project controls · Acronym or initialism · Industry-wide — A short-term plan recording reliable work commitments for the coming week.
In practice: The forepersons agree on the WWP after checking constraints.
Lean Construction Institute ↗
WWR — Welded wire reinforcement
Concrete & masonry · Acronym or initialism · Industry-wide — A reinforcement product made from intersecting wires joined by welding.
In practice: The slab schedule specifies WWR size and placement.
American Concrete Institute ↗