HEAT VENTILATION AND AIR CONDITIONER SHORT FORMS FULL FORM SHORT ANSWER Make sure to check the front part of the drawings set for abbreviations used inside the engineering drawings because the list of abbreviations sometimes may vary from an office to another A AHU : AIR HANDLING UNITAC : Air Conditioning / ALTERNATIVE CURRENT ACB : AIR CIRCUIT BREAKER A : Air / Compressed Air ACD : Automatic Control Damper AD : Access Door AF : Air Foil / Airofoil / Air flow AMP : Ampere AP : Access Panel APD : Air Pressure Drop AS : Air Stream ATC : Automatic Temperature Control ATM : Atmosphere B BDD : Back Draft DamperBHP : Brake Horsepower BI : Backwards Inclined BOD : Bottom of Duct BTU : British Thermal Unit BTUH : BTU per Hour BMS : BUILDING MANAGEMENT SYSTEM BAS : BUILDING AUTOMATION SYSTEM C C : Celsius TemperatureCSU : CEILING SUSPENDED UNIT CENT : Center / Centrifugal CF : Cubic Feet CFM : Cubic Feet per Minute CH : Chilled / Chiller CHW : Chilled Water CHWR : Chilled Water Return CHWS : Chilled Water Supply CHWP : Chilled Water Pump 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 CWP : Condenser Water Pump CCTV : CLOSED CIRCUIT TELEVISION D D : DrainDB : Dry Bulb Temperature DEG : Degree DDC : Direct Digital Control DIA : Diameter DIM : Dimension DP : Differential Pressure DC : DIRECT CURRENT DOL : DIRECT ON LINE DB : DISTRIBUTION BOARD DX : Direct Expansion E ELCB : EARTH LEAKAGE CIRCUIT BREAKEREA : Exhaust Air / Each 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 / EX : Exhaust EXT : External EXP : Expansion F F : Fahrenheit TemperatureFA : Fresh Air FCU : FAN COIL UNIT FA : Free Area / Fire Alarm FC : Flexible Connection FD : Floor Drain / Fire Damper / 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 G : GasGA : Gauge GAL : Gallons GALV : Galvanized GFU : Glycol Feed Unit GPH : Gallons per Hour GPM : Gallons per Minute GR : Grade H HVAC : HEAT VENTILATION AND AIR CONDITIONERHB : Hose Bib Connection HD : Head HP : Horsepower / High Point / High Pressure HR : Hour HRU : Heat Recovery Unit HTG : Heating HWP : Hot Water Pump HWR : Hot Water Return HWS : Hot Water Supply HZ : Hertz Cycles per Second I ID : Inside Diameter IN : Inches K KW : KILO WATT KVA : KILO VOLT AMPERES L LAT : Leaving Air TemperatureLB : Pound LF : Linear Feet LD : Linear Diffuser LP : Low Point / Low Pressure LPS : Low Pressure Steam LRA : Locked Rotor Amps LUVR / LVR : Louver LVDR : Louvered Door LVG : Leaving LWT : Leaving Water Temperature M M : MassMAX : Maximum MBH : 1000 BTUH / Mega British Thermal Unit per Hour MCA : Minimum Circuit Amps MD : Motorized Damper MECH : Mechanical MIN : Minimum MU : Make Up Water MUA : Make Up Air MCCB : MOLDED CASE CIRCUIT BREAKER MCB : MINIATURE CIRCUIT BREAKER N NC : Noise Criteria / Normally ClosedNO : Normally Open NOM : Nominal O OA : Outside AirOAI : Outside Air Intake OC : On Center OD : Outside Diameter ODP : Open Drip Proof OV : Outlet Velocity P PCF : Pounds per Cubic FootPD : Pressure Drop PH : Phase PRV : Pressure Reducing Valve PSI : POUND per SQUARE INCHES PSIA : POUND per SQUARE INCHES Absolute PSID : Pounds per Square Inch Differential PSIG : Pounds per Square Inch Gauge PVC : Polyvinyl Chloride PAC : PRECISION AIR CONDITIONER PCB : PRINTED CIRCUIT BOARD PLC : PROGRAMMABLE LOGIC CONTROL R R : RadiusRA : Return Air RET : Return RH : Relative Humidity RLA : Running Load Amps RLF : Relief RPM : REVOLUTION PER MINUTE / Rotation RTU : Roof Top Unit S SA : Supply AirSCR : Screen SCT : Saturated Condensing Temperature SD : Smoke Detector / 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 STP : SEWAGE TREATMENT PLANT T TR : TONNAGE OF REFRIGERANTTON : 12000 BTUH Cooling Capacity T : Temperature / Thermostat TEFC : Totally Enclosed Fan Cooled TEMP : Temperature TSP : Total Static Pressure TSTAT : Thermostat TYP : Typical TC : Temperature Control V V : VoltsVAV : VARIABLE ADJUSTABLE VALVE / Variable Air Volume VD : Volume Damper VEL : Velocity VFD : VARIABLE FREQUENCY DRIVE VCD : VOLUME CONTROL DUMBER VRF : VARIABLE REFRIGERANT FLOW VRV : VARIABLE REFRIGERANT VALVE U UC : Undercut Door UPS : UNINTERRUPTIBLE POWER SUPPLY W WB : Wet Bulb TemperatureWC : Water Column WG : Water Gauge WPD : Water Pressure Drop WTD : Water Temperature Difference