Free reference
Abbreviations
Drawings abbreviate because there is no room not to. 289 of the abbreviations you will meet on a US set, written out plainly, with the discipline each one is most at home on. Filter by any part of the mark or of its meaning.
Read the project legend first
Every set carries its own abbreviations list, normally on a general sheet near the front, and that list governs on that project. A handful of marks genuinely differ between offices and between disciplines: EL means an elevation height to a structural engineer and an elevation drawing to an architect, and BM is a beam on a framing plan and a benchmark on a site plan. Context settles both, and the project legend settles the rest.
The four worth knowing before anything else are CLR, TYP, U.O.N. and V.I.F., because each of them changes what a drawing is instructing you to do rather than merely naming a thing.
The list
Showing 289 of 289 abbreviations.
| Abbreviation | Meaning | Usually seen on |
|---|---|---|
| A.B. | Anchor bolt | Structural |
| A.C.T. | Acoustical ceiling tile | Architectural |
| A.D. | Area drain | Plumbing |
| A.F.F. | Above finished floor, the datum most interior heights are measured from | Architectural |
| AB | Anchor bolt | Structural |
| ABV | Above | General |
| AC | Air conditioning | Mechanical |
| ACT | Acoustical ceiling tile | Architectural |
| AD | Area drain | Plumbing |
| ADJ | Adjustable | General |
| AFF | Above finish floor | General |
| AHU | Air handling unit | Mechanical |
| AL | Aluminium | Architectural |
| ALT | Alternate, a priced option that may or may not be taken | General |
| ALUM | Aluminium | Architectural |
| APPROX | Approximate | General |
| ARCH | Architect or architectural | General |
| ASPH | Asphalt | Civil |
| B.O. | Bottom of, as in bottom of footing or bottom of steel | Structural |
| BD | Board | Architectural |
| BLDG | Building | General |
| BLK | Block | Architectural |
| BLKG | Blocking, solid framing added to receive a fixing | Architectural |
| BM | Beam | Structural |
| BM. | Benchmark, a fixed point of known elevation | Civil |
| BOT | Bottom | General |
| BRG | Bearing | Structural |
| BRK | Brick | Architectural |
| BSMT | Basement | Architectural |
| BTU | British thermal unit | Mechanical |
| BW | Both ways | Structural |
| C.I.P. | Cast in place, concrete poured in its final position | Structural |
| C.J. | Control joint, a formed crack line in concrete or masonry | Architectural |
| C.L. | Centre line | General |
| C.M.U. | Concrete masonry unit | Structural |
| C.O. | Cleanout, an access fitting on a drainage line | Plumbing |
| CAB | Cabinet | Architectural |
| CB | Catch basin | Civil |
| CFM | Cubic feet per minute, a rate of airflow | Mechanical |
| CG | Corner guard | Architectural |
| CIP | Cast in place | Structural |
| CJ | Control joint | Architectural |
| CL | Centre line | General |
| CLG | Ceiling | Architectural |
| CLR | Clear, a distance that must be held in the finished work | General |
| CMU | Concrete masonry unit | Architectural |
| CO | Cleanout | Plumbing |
| COL | Column | Structural |
| CONC | Concrete | Structural |
| CONN | Connection | General |
| CONST | Construction | General |
| CONT | Continuous | General |
| CORR | Corridor | Architectural |
| CPT | Carpet | Architectural |
| CT | Ceramic tile | Architectural |
| CU | Condensing unit | Mechanical |
| CU FT | Cubic feet | General |
| CW | Cold water | Plumbing |
| D.F. | Drinking fountain | Plumbing |
| D.S. | Downspout, the vertical pipe taking roof water down a wall | Plumbing |
| DBL | Double | General |
| DEMO | Demolish or demolition | General |
| DET | Detail | General |
| DF | Drinking fountain | Plumbing |
| DIA | Diameter | General |
| DIM | Dimension | General |
| DISC | Disconnect switch | Electrical |
| DN | Down, used at stairs and ramps to give direction of travel | Architectural |
| DR | Door | Architectural |
| DS | Downspout | Plumbing |
| DWG | Drawing | General |
| E.J. | Expansion joint | Structural |
| E.W.C. | Electric water cooler | Plumbing |
| EA | Each | General |
| EF | Exhaust fan | Mechanical |
| EJ | Expansion joint | Structural |
| EL | Elevation, meaning a height above a datum | General |
| ELEC | Electrical | Electrical |
| ELEV | Elevator, or an elevation drawing depending on context | Architectural |
| EM | Emergency | Electrical |
| EMER | Emergency | General |
| ENCL | Enclosure | General |
| EQ | Equal, meaning divide the run into equal parts rather than measure a figure | General |
| EQUIP | Equipment | General |
| EWC | Electric water cooler | Plumbing |
| EXH | Exhaust | Mechanical |
| EXIST | Existing, work already in place and not part of the new contract | General |
| EXP | Exposed | General |
| EXT | Exterior | Architectural |
| F.D. | Floor drain | Plumbing |
| F.E.C. | Fire extinguisher cabinet | Architectural |
| F.F. | Finished floor | Architectural |
| F.O.C. | Face of concrete | Structural |
| F.O.F. | Face of finish | Architectural |
| F.O.S. | Face of stud, a common face for plan dimensions on framed work | Architectural |
| FA | Fire alarm | Electrical |
| FD | Floor drain | Plumbing |
| FDN | Foundation | Structural |
| FE | Fire extinguisher | Architectural |
| FF | Finish floor | General |
| FFE | Finish floor elevation | Civil |
| FIN | Finish | Architectural |
| FLR | Floor | Architectural |
| FOC | Face of concrete | General |
| FOF | Face of finish | General |
| FOS | Face of stud | General |
| FPM | Feet per minute | Mechanical |
| FT | Foot or feet | General |
| FTG | Footing | Structural |
| FURR | Furring, light framing added to a surface to carry a finish | Architectural |
| G.C. | General contractor | General |
| GA | Gauge | General |
| GALV | Galvanised | General |
| GB | Grab bar | Architectural |
| GC | General contractor | General |
| GFCI | Ground fault circuit interrupter | Electrical |
| GL | Glass or glazing | Architectural |
| GND | Ground | Electrical |
| GRD | Grade, the level of the ground | Civil |
| GWB | Gypsum wall board | Architectural |
| GYP | Gypsum | Architectural |
| H.B. | Hose bibb, an outdoor tap | Plumbing |
| H.M. | Hollow metal, the usual material for rated doors and frames | Architectural |
| HB | Hose bibb | Plumbing |
| HC | Hollow core | Architectural |
| HDR | Header, the member over an opening | Structural |
| HGT | Height | General |
| HM | Hollow metal | Architectural |
| HORIZ | Horizontal | General |
| HP | Horsepower | Mechanical |
| HR | Hour, used with a fire resistance rating | Architectural |
| HT | Height | General |
| HVAC | Heating, ventilating and air conditioning | Mechanical |
| HW | Hot water | Plumbing |
| HWY | Highway | Civil |
| I.D. | Inside diameter | Mechanical |
| ID | Inside diameter | General |
| IE | Invert elevation, pipe bottom | Civil |
| IN | Inch or inches | General |
| INSUL | Insulation | Architectural |
| INT | Interior | Architectural |
| INV | Invert, the inside bottom of a pipe, used to set drainage levels | Civil |
| JAN | Janitor | Architectural |
| JST | Joist | Structural |
| JT | Joint | General |
| KIT | Kitchen | Architectural |
| KO | Knockout, a removable panel in an enclosure | Electrical |
| KVA | Kilovolt ampere | Electrical |
| KW | Kilowatt | Electrical |
| L.F. | Linear feet | General |
| LAV | Lavatory, a washbasin | Plumbing |
| LB | Pound | General |
| LDG | Landing | Architectural |
| LF | Linear foot | General |
| LLH | Long leg horizontal | Structural |
| LP | Lighting panel | Electrical |
| LT | Light | Electrical |
| LTG | Lighting | Electrical |
| LVR | Louvre | Mechanical |
| MAINT | Maintenance | General |
| MAS | Masonry | Architectural |
| MATL | Material | General |
| MAX | Maximum, a limit rather than a target | General |
| MBH | Thousand Btu per hour | Mechanical |
| MCA | Minimum circuit ampacity | Electrical |
| MECH | Mechanical | Mechanical |
| MEP | Mechanical, electrical and plumbing taken together | General |
| MFR | Manufacturer | General |
| MIN | Minimum, a limit rather than a target | General |
| MISC | Miscellaneous | General |
| MO | Masonry opening | Architectural |
| MTD | Mounted | General |
| MTL | Metal | General |
| N.I.C. | Not in contract, shown for information but supplied by others | General |
| N.T.S. | Not to scale, so the drawing must not be measured | General |
| NIC | Not in contract | General |
| NO | Number | General |
| NOM | Nominal, a naming size rather than a measured one | General |
| NTS | Not to scale | General |
| O.C. | On centre, the spacing between the centres of repeated members | Structural |
| O.D. | Outside diameter | Mechanical |
| O.H. | Overhead | General |
| OA | Outside air | Mechanical |
| OC | On centre | General |
| OD | Outside diameter | General |
| OH | Overhead | General |
| OPNG | Opening | Architectural |
| OPP | Opposite, often with hand, meaning a mirrored condition | General |
| OWSJ | Open web steel joist | Structural |
| P.L. | Property line | Civil |
| P.T. | Pressure treated | Structural |
| PL | Property line | Civil |
| PLAM | Plastic laminate | Architectural |
| PLBG | Plumbing | Plumbing |
| PLYWD | Plywood | Architectural |
| PNL | Panel | Electrical |
| PR | Pair | General |
| PSF | Pounds per square foot | Structural |
| PSI | Pounds per square inch | General |
| PT | Point | General |
| PTD | Painted | Architectural |
| PVC | Polyvinyl chloride | Plumbing |
| QTY | Quantity | General |
| R | Riser | Architectural |
| R.A. | Return air | Mechanical |
| R.D. | Roof drain | Plumbing |
| R.O. | Rough opening, the framed size before a frame is fitted | Architectural |
| R.O.W. | Right of way | Civil |
| RA | Return air | Mechanical |
| RAD | Radius | General |
| RCP | Reflected ceiling plan | Architectural |
| RD | Roof drain | Plumbing |
| REF | Reference | General |
| REINF | Reinforcing or reinforcement | Structural |
| REQD | Required | General |
| RET | Return | Mechanical |
| REV | Revision | General |
| RM | Room | Architectural |
| RO | Rough opening | Architectural |
| ROW | Right of way | Civil |
| RTU | Rooftop unit | Mechanical |
| S.A. | Supply air | Mechanical |
| S.C. | Solid core | Architectural |
| SA | Supply air | Mechanical |
| SAN | Sanitary, the foul drainage system | Plumbing |
| SCHED | Schedule | General |
| SD | Smoke detector | Electrical |
| SECT | Section | General |
| SF | Square feet | General |
| SHT | Sheet | General |
| SIM | Similar, meaning read the referenced drawing and adapt it | General |
| SLT | Skylight | Architectural |
| SPEC | Specification | General |
| SQ | Square | General |
| SS | Stainless steel | Architectural |
| ST | Storm drain | Civil |
| STC | Sound transmission class, a rating of how much sound an assembly stops | Architectural |
| STD | Standard | General |
| STL | Steel | Structural |
| STOR | Storage | Architectural |
| STRUCT | Structural | Structural |
| SUSP | Suspended | Architectural |
| SYM | Symmetrical | General |
| T | Thermostat | Mechanical |
| T.O. | Top of, as in top of slab, top of steel or top of wall | Structural |
| T.O.S. | Top of slab or top of steel, depending on the discipline | Structural |
| TB | Towel bar | Architectural |
| TBD | To be determined | General |
| TEL | Telephone | Electrical |
| TEMP | Tempered, when applied to glass | Architectural |
| THK | Thick or thickness | General |
| TO | Top of | General |
| TOC | Top of concrete | Structural |
| TOIL | Toilet | Architectural |
| TOS | Top of steel | Structural |
| TOW | Top of wall | Architectural |
| TYP | Typical, meaning the note applies at every similar condition | General |
| U.O.N. | Unless otherwise noted | General |
| UG | Underground | Civil |
| UNFIN | Unfinished | Architectural |
| UNO | Unless noted otherwise | General |
| UR | Urinal | Plumbing |
| V.C.T. | Vinyl composition tile | Architectural |
| V.I.F. | Verify in field, meaning the figure depends on what is already built | General |
| VB | Vapour barrier | Architectural |
| VCT | Vinyl composition tile | Architectural |
| VENT | Ventilation, or a vent pipe on a plumbing drawing | Mechanical |
| VERT | Vertical | General |
| VEST | Vestibule | Architectural |
| VIF | Verify in field | General |
| VOL | Volume | General |
| VTR | Vent through roof | Plumbing |
| W | Water, or a wide flange shape | General |
| W.C. | Water closet | Plumbing |
| W.H. | Water heater | Plumbing |
| W.P. | Waterproofing | Architectural |
| W.R.B. | Water resistive barrier | Architectural |
| W.W.F. | Welded wire fabric, sheet reinforcement for slabs | Structural |
| WC | Water closet | Plumbing |
| WD | Wood | Architectural |
| WDW | Window | Architectural |
| WH | Water heater | Plumbing |
| WM | Water meter | Plumbing |
| WP | Weatherproof | Electrical |
| WT | Weight | General |
| WWF | Welded wire fabric | Structural |
| WWM | Welded wire mesh | Structural |
| XFMR | Transformer | Electrical |
| YD | Yard | General |