HVAC Abbreviations
The list of abbreviations used in a set of engineering drawings varies from office to office. Be sure to check the front section of the drawing set for the abbreviations used within.
A Air or Compressed Air AC Air Conditioning ACD Automatic Control Damper AD Access Door AF Air Foil AHU Air Handling Unit AMP Ampere AP Access Panel APD Air Pressure Drop AS Air Stream ATC Automatic Temperature Control ATM Atmosphere BDD Back-Draft Damper BHP Brake Horsepower BI Backwards Inclined BOD Bottom of Duct BTU British Thermal Unit BTUH BTU per Hour CENT Center or Centrifugal CF Cubic Feet CFM Cubic Feet per Minute CH Chilled or Chiller CHW Chilled Water CHWR Chilled Water Return CHWS Chilled Water Supply CO Carbon Monoxide CONN Connection CT Cooling Tower CTBD Cooling Tower Blow Down CUH Cabinet Unit Heater CWR Condenser Water Return CWS Condenser Water Supply D Drain DB Dry Bulb (Temperature) DEG Degree DDC Direct Digital Control DIA Diameter DIM Dimension DP Differential Pressure
EA Each or Exhaust Air EAHU Exhaust Air Handling Unit EAT Entering Air Temperature EF Exhaust Fan EMER Emergency EMS Energy Management System ESP External Static Pressure ET Expansion Tank EUH Electrical Unit Heater EWT Entering Water Temperature EXH or EX Exhaust EXT External EXP Expansion F Fahrenheit FA Free Area or Fire Alarm FC Flexible Connection FCU Fan Coil Unit FD Floor Drain, Fire Damper, or Fire Department FLA Full Load Amps FLEX Flexible FLRDR Floor Drain FPM Feet per Minute FPS Feet per Second FRP Fiberglass Reinforced Plastic FS Flow Switch FT Feet FTR Fin Tube Radiation G Gas GA Gauge GAL Gallons GALV Galvanized GFU Glycol Feed Unit GPH Gallons per Hour GPM Gallons per Minute GR Grade HB Hose Bib (Connection) HD Head HP Horsepower or High Point HR Hour HRU Heat Recovery Unit HTG Heating HWR Hot Water Return HWS Hot Water Supply HZ Hertz (Cycles per Second) ID Inside Diameter IN Inches KW Kilowatt LAT Leaving Air Temperature LB Pound LF Linear Feet LD Linear Diffuser LP Low Point LPS Low Pressure Steam LRA Locked Rotor Amps LUVR or LVR Louver LVDR Louvered Door LVG Leaving LWT Leaving Water Temperature MAX Maximum MBH 1000 BTUH MCA Minimum Circuit Amps MD Motorized Damper MECH Mechanical MIN Minimum MU Make-Up Water MUA Make-Up Air NC Noise Criteria or Normally Closed NO Normally Open NOM Nominal OA Outside Air OAI Outside Air Intake OC On Center OD Outside Diameter ODP Open Drip Proof OV Outlet Velocity PCF Pounds per Cubic Foot PD Pressure Drop PH Phase PRV Pressure Reducing Valve PSI Pounds per Square Inch PSIA Pounds per Square Inch – Absolute PSID Pounds per Square Inch – Differential PSIG Pounds per Square Inch – Gauge PVC Polyvinyl Chloride
R Radius RA Return Air RET Return RH Relative Humidity RLA Running Load Amps RLF Relief RPM Revolutions per Minute RTU Roof-Top Unit SA Supply Air SCR Screen SCT Saturated Condensing Temperature SD Smoke Detector or Smoke Damper SE Smoke Exhaust SEN Sensible SFD Combination Smoke / Fire Damper SHC Sensible Heat Capacity SP Static Pressure SF Square Feet SS Stainless Steel SUP Supply T Temperature or Thermostat TEFC Totally Enclosed Fan Cooled TEMP Temperature TON 12,000 BTUH (Cooling Capacity) TSP Total Static Pressure TSTAT Thermostat TYP Typical UC Undercut (Door) V Volts VAV Variable Air Volume VD Volume Damper VEL Velocity VFD Variable Frequency Drive WB Wet Bulb Temperature WC Water Column WG Water Gauge WPD Water Pressure Drop WTD Water Temperature Difference
