HVAC Abbreviations
Commonly used HVAC abbreviations and their meanings.
| Abbreviation | Definition |
|---|---|
| A | Compressed air line or area |
| ABC | Above ceiling |
| AC | Air chamber, alternating current |
| A/C | Air conditioning |
| AFF | Above finished floor |
| AFG | Above finished grade |
| AL | Aluminum |
| AMB | Ambient |
| AMP | Ampere |
| ARR | Arrangement |
| ATC | Automatic temperature control, at ceiling |
| ATM | Atmosphere |
| AUTO | Automatic |
| AUX | Auxiliary |
| AVG | Average |
| BBD | Boiler blowdown |
| BF | Boiler feed |
| BHP | Boiler horsepower, brake horsepower |
| BOD | Bottom of duct |
| BOP | Bottom of pipe |
| BOT | Bottom |
| BP | Back pressure |
| B & S | Bell-and-spigot |
| BSMT | Basement |
| BTU | British thermal unit |
| BV | Butterfly valve |
| °C | Degrees Celsius |
| C | Condensate line |
| C to C | Center to center |
| CA | Compressed air |
| CAL | Calorie |
| CAP | Capacity |
| CD | Condensate drain |
| CF | Chemical feed, cubic foot |
| CFH | Cubic feet per hour |
| CFM | Cubic feet per minute |
| CI | Cast iron |
| CIRC | Circular |
| CL | Center line |
| CM | Centimetre |
| CM2 | Square centimetre |
| CO | Clean out |
| COL | Column |
| CONC | Concrete, concentric |
| CONN | Connect, connection |
| CONT | Continuation |
| CPVC | Chlorinated polyvinyl chloride |
| CR | Condenser return |
| CRW | Chemical resistant waste |
| CS | Condenser supply |
| CTR | Center |
| CU | Cubic |
| CU FT. | Cubic feet |
| CU IN. | Cubic inches |
| CV | Check valve |
| CW | Cold water |
| CWR | Chilled/cold water return |
| CWS | Chilled/cold water supply |
| D | Drain, deep |
| DB | Dry bulb |
| DDC | Direct digital control |
| DEG | Degree |
| DELTAT | Temperature difference |
| DET | Detail |
| DIA | Diameter |
| DISC | Disconnect |
| DN | Down |
| DP | Dew point temperature |
| DR | Drain |
| DWG | Drawing |
| EA | Exhaust air, each |
| EAT | Entering temperature |
| EATR | Exhaust Air Transfer Ratio |
| E to C | End to center |
| EER | Energy efficient ratio |
| EFF | Efficiency |
| EJ | Expansion joint |
| EL | Elevation |
| ELB | Elbow |
| ELEC | Electrical |
| ENT | Entering |
| ERV | Energy Recovery Ventilator |
| ESP | External static pressure |
| ET | Expansion tank |
| EVAP | Evaporator |
| EWT | Entering water temperature |
| EXH | Exhaust |
| EXP | Expansion |
| EXST | Existing |
| EXT | External |
| °F | Degrees Fahrenheit |
| F | Fahrenheit |
| FC | Flexible connector, flexible connection |
| FCO | Floor clean out |
| FD | Floor drain |
| FDW | Feed water |
| FEC | Fire extinguisher cabinet |
| FF | Finish floor |
| FG | Finish grade |
| FHC | Fire hose cabinet |
| FLA | Full load amps |
| FLR | Floor |
| FM | Flow meter |
| FO | Fuel oil |
| FOV | Flush out valve |
| FPM | Feet per minute |
| FPS | Feet per second |
| FS | Flow switch, federal specs |
| FT | Foot, feet |
| FTG | Fitting |
| FU | Fixture unit |
| FV | Flush valve |
| G | Gram, gas line |
| GA | Gauge |
| GAL | Gallons |
| GALV | Galvanized |
| GL.V | Globe valve |
| GND | Ground |
| GPD | Gallons per day |
| GPH | Gallons per hour |
| GPM | Gallons per minute |
| GPS | Gallons per second |
| GR | Grain |
| GV | Gate valve |
| GWH | Gas water heater |
| H2O | Water |
| HB | Hose bibb |
| HD | Head |
| Hg | Mercury |
| HGT | Height |
| HMD | Humidity |
| HORIZ | Horizontal |
| HP | Horsepower |
| HR | Hour |
| HRV | Heat Recovery Ventilator |
| HTD | Heated |
| HTR | Heater |
| HW | Hot water |
| HWH | Hot water heater |
| HWR | Hot water return, hot water riser |
| HWS | Hot water supply |
| HWT | Hot water tank |
| HZ | Hertz |
| ID | Inside diameter |
| IN. | Inch |
| INHg | Inches of mercury |
| INSUL | Insulation |
| INT | International |
| INTL | Internal |
| IPS | Iron pipe size |
| IV | Indirect vent |
| IW | Indirect waste |
| J | Joule |
| K | Kelvin |
| KG | Kilogram |
| KM | Kilometre |
| KM2 | Square kilometre |
| KPA | Kilo pascal |
| KS | Kitchen sink |
| KW | Kilowatt |
| L | Length, liter |
| LAT | Leaving air temperature |
| LB. | Pound |
| LBF | Pound-force |
| LIQ | Liquid |
| LP | Low pressure |
| LRA | Locked rotor amps |
| LVL | Level |
| LVR | Louver |
| LWT | Leaving water temperature |
| M | Meter |
| M2 | Square meter |
| M TYPE | Lightest type of rigid copper pipe |
| MAN | Manual |
| MAT | Mixed air temperature |
| MAX | Maximum |
| MBH | Thousand British thermal units per hour |
| MFR | Manufacturer |
| MG | Milligram |
| MGD | Millions gallons per day |
| MIN | Minimum or minute |
| ML | Milliliter |
| MM | Millimetre |
| MM3 | Cubic millimetre |
| MPT | Male pipe thread |
| MTD | Mounted |
| MU | Make up |
| NA | Not applicable |
| NC | Normally closed |
| NEG | Negative |
| NIC | Not in contact |
| NO | Normally open |
| NPHP | Name plate horsepower |
| NPS | Nominal pipe size |
| NPSH | Net positive suction head |
| NTS | Not to scale |
| O | Oxygen |
| OA | Outside air |
| OAT | Outside temperature |
| OC | On center |
| OD | Outside diameter |
| OED | Open end duct |
| OF | Overflow |
| OV | Outlet velocity |
| OZ. | Ounce |
| PA | Pascal |
| PC | Plumbing contractor |
| PCR | Pumped condensate return |
| PD | Pressure drop |
| PF | Power factor |
| PG | Pressure gauge |
| PL | Plate |
| PNEU | Pneumatic |
| PRESS | Pressure |
| PROP | Propeller |
| PRV | Pressure reducing valve |
| PSI | Pounds per square inch |
| PSIA | Pound per square inch absolute |
| PSIG | Pound per square inch gauge |
| PV | Plug valve |
| QTY | Quantity |
| RA | Return air |
| RAD | Radius |
| RAT | Return air temperature |
| RD | Roof drain |
| R/E | Return and exhaust |
| RECOV | Recovery |
| RED | Reducer |
| REF | Reference |
| RH | Relative humidity |
| REQD | Required |
| REV | Revision |
| RL | Refrigerant liquid |
| RLA | Rated Load Amperes |
| RM | Room |
| RS | Refrigerant suction |
| RTN | Return |
| RV | Relief valve |
| S | Switch |
| SA | Shock absorber, supply air |
| SAT | Supply air temperature |
| SCH | Schedule |
| SDT | Saturated discharge temperature |
| SEC | Seconds, secondary |
| SENS | Sensible |
| SEP | Separate |
| SEQ | Sequence |
| SER | Series |
| SERV | Service |
| SF | Service factor |
| SHT | Sheet |
| SI | International systems of units |
| SOL | Solenoid |
| SP | Static pressure |
| SPEC | Specification |
| SQ. | Square |
| SQ.FT. | Square feet |
| SS | Stainless steel |
| SSH | Static suction head |
| SST | Saturated suction temperature, stainless steel |
| STD | Standard |
| STH | Static total head |
| STL | Steel |
| SUCT | Suction |
| SPLY | Supply |
| SV | Service |
| SVH | Static velocity head |
| SW | Service weight |
| SWS | Service water |
| TD | Temperature difference |
| TDH | Total dynamic head |
| TEMP | Temperature |
| TH | Thermometer |
| THK | Thick |
| TP | Total pressure |
| TSP | Total static pressure |
| UF | Under floor |
| UH | Unit heater |
| V | Vent, volt, volume |
| VAC | Vacuum |
| VAV | Variable air volume |
| VB | Vacuum breaker |
| VCI | Vacuum cleaning inlet |
| VCL | Vacuum cleaning line |
| VEL | Velocity |
| VERT | Vertical |
| VIB | Vibration |
| VOL | Volume |
| VSD | Variable speed drive |
| VP | Velocity pressure |
| VTR | Vent thru roof |
| W | Watt, width, wide |
| WB | Wet bulb |
| WCO | Wall clean out |
| WG | Water gauge |
| WH | Water heater |