As isometric piping drawing become denser in information and crowded with compound, the piping engineer start to use piping abbreviations in the design work to reduce the space requirement of the callout of the fitting or in the note section of the mechanical piping drawing.
The list below includes most of the piping abbreviation used in the piping drawings, plumbing abbreviation, Plumbing fittings abbreviations, steam piping abbreviation, flow diagram, piping arrangement drawing, isometric…
Each engineering companies or operating companies have their own abbreviation list that should be used for a specific drawing or a specific situation.
I did my best to included most used abbreviation from several company abbreviations and different industries (refinery, plumbing, abbreviation for nonmetals, different type of pipes and fittings…). A complete list of piping abbreviations is almost impossible to compile as I do not have access to all engineering and operating companies.
A Alarm A Anchor ABS Acrylonitrile Butadiene Styrene ACCUM Accumulator AD Area Drain AFC Automatic Flow Control AFF Above Finished Floor AHR Air Hose Reel AHU Air Handling Unit AISI American Iron and Steel Institute AL Aluminum ALT Alternate ANSI American National Standards Institute AP Access Panel API American Petroleum Institute AS Air Separator ASA American Standards Association ASA American Supply Association / American Standards Association Asb Asbestos (Gaskets) ASME The American Society of Mechanical Engineers ASSY Assembly ASTM American Society for Testing and Materials ATMOS Atmosphere AUX Auxiliary AVG Average AWWA American Water Works Association AZ Azimuth A Piping, Plumbing Abbreviation. B
B Beveled B&S Bell and Spigot BB Bolted Bonnet BBE Bevel Both Ends BBL Barrel (s) BC Bolt Circle BD Blow Down BDD Backdraft / Pressure Relief Damper Bdr Bleed ring BE Beveled End (s) BF Blind Flange Bfy Butterfly (valve) BL Battery Limits Bld Blind (flange) Bld Spectacle blind (plate between flanges) BLDG Building BLE Bevel Large End Blk Black (pipe) BOE Bevel One End BOM Bill of Materials BOP Bottom of Pipe Brz Bronze (valve) BSE Bevel Small End BTU British Thermal Unit BV Ball Valve BV Balance Valve BW Butt-weld B Piping, Plumbing Abbreviation. C
C Compression CB Catch Basin Ch. Op. Chain Operator Chk Check (valve) CHKV Check Valve CI Cast Iron CL Clearance CL Centerline Cm Centimeter CO Clean Out COL Column COLS Columns CONC Concentric COND Condensate CONN Connection CONV Hydronic Convector CORR Corrosion Cpl Coupling CPLG Coupling CPVC Chlorinated Polyvinyl Chloride CPVC Chlorinated Polyvinyl Chloride CS Carbon Steel CS Cast Steel CS Cold Spring CS Cap Screw Csg Casing Csw Concentric swage CTRLV Control Valve CTS Copper Tube Size Cu Cubic CUH Cabinet Unit Heater CW Chain Wheel / Cold Water CWO Chain Wheel Operator CWP Cold Water Pressure CWR Cooling Water Return CWS Cooling Water Supply C Piping, Plumbing Abbreviation. D
D&T Drill and tap D&W Doped and wrapped (pipe) DA Directional Anchor DB Dry Bulb DES Double extra strong DF Drinking Fountain DF Drain Funnel DFT Dry film thickness DI Ductile iron DIA Diameter Dia Diameter DIFF Diffuser DIM Dimension Dim Dimension DISCH Discharge Ditto Do not use this term. DR Drain DRWN Drawn DS Downspout DSAW Double sub‐merged arc welded (pipe) DW Dummy Weld DWG Drawing Dwg # Drawing number DWV Drain/Waste/Vent DWV Drainage waste & vent DXC Direct Expansion Cooling Coil D Piping, Plumbing Abbreviation. E
E East EA Exhaust Air Ea. Each EAF Electric arc furnace EAT Entering Air Temperature EBBR Electric Base Board Radiation EC Electrical Contractor ECC Eccentric ECONV Electric Convector ECUH Electric Cabinet unit Heater EF Exhaust Fan EG Exhaust Grille EL Elevation Elec Electrical ELEV Elevation ELL Elbow Eol Elbolet EOM End Of Main Drip EQUIP Equipment ERW Electric resistance weld (pipe) Esw Eccentric swage ET Expansion Tank EUE External upset ends EWC Electric Water Cooler EWH Electric Water Heater Ex.hvy Extra Heavy Ex.stg Extra Strong EXCH Exchanger EXIST Existing Exp jt Expansion joint EXTG, E Existing E Piping, Plumbing Abbreviation. F
F&D Faced and drilled (flanged) F/F Face of flange F/F Face-to-Face FA Flow Alarm FAB Fabricate/fabricator FAS Free along side FBO Furnished By Others FD Floor Drain FD Fire Damper FDN Foundation FE Flanged ends FE Flow Element Fem Female (ends) FF Flat Face FF Full face FHT Female hose threads FI Flow Indicator FIC Flow Indicating Controller Fig Figure (number) FIP Female iron pipe FL Flange FLD FAB Field Fabricate Flex Flexitallic (gasket brand name) Flg. Flange Flgd Flanged ends FLR Floor FNPT Female National Pipe Thread Taper FOB Flat on Bottom FOB Free On Board FOT Flat on Top FR Flow Recorder FRC Flow Recording Controller FS Forged steel FS Field Support FS Forged Steel FSD Flat Side Down FSD Combination Fire/Smoke Damper FSU Flat Side Up Ft Feet/foot Ftg Fitting FTR Hydronic Finned Tube Radiation FUE Female union end FW Field weld FW Fire Water F Piping, Plumbing Abbreviation. G
G Gauge or gage Gal Gallon Galv Galvanized GaV Gate Valve GC General Contractor GCO Grade Cleanouts GEN General GG Gauge glass GJ Ground joint (union) Glb Globe (valve) GPD Gallon Per Day GPF Gallons per flush GPH Gallons Per Hour GPM Gallons per minute GPR Gas Pressure Regulator GR Grade GRS Gas Regulator Station Gsk Gasket GT Grease Trap GVTR Gas Vent through Roof G Piping, Plumbing Abbreviation. H
HC Hose coupling Hdr Header Hex Six‐sided head, bolt, plug etc. HN Heat number HT Hose threads Hvy Heavy HW Hot water HCV Hand Control Valve HIC Hand Indicating Controller HLL High Liquid Level HOR Horizontal HP High Pressure HPFS High Point Finished Surface HPP High Point Paving HR Hanger Rod HR Hour HTR Heater HVAC Heating, Ventilating, and Air Conditioning HYD Hydraulic HAZ Heat-affected zone HSLA High-strength, low-alloy HIC Hydrogen-induced cracking H Hub HB Hose Bibb HTG Heating H&CW Hot and Cold Water HD Hub Drain HDPE High Density Polyethylene Hex Heat Exchanger HG Mercury HP Horsepower HWCP Hot Water Circulating Pump HYD Hydrant HZ Hertz H Piping, Plumbing Abbreviation. I
IBBM Iron body bronze mounted (valve) ID Inside diameter IPS Iron pipe size IS&Y Inside screw & yoke (valve) ISO Isometric (drawing) IUE Internal upset ends IA Instrument Air IA Insulation (anti sweat) IC Insulation (cold) ID Inside Diameter IDD Inside Depth of Dish IET Electric Trace IGT Glycol Trace IH Insulation (heat conservation) IN Inch(es) INS Insulate or Insulation INST Instrumentation INV Invert Elevation IPS Iron Pipe Size IS Insulation Safety ISA Instrumentation Society of America ISO International Organization for Standardization ISO Isometric (drawing) IST Steam Trace IE Invert Elevation INV Invert IPC International Plumbing Code IPS Iron pipe size INV. EL Invert Elevation I Piping, Plumbing Abbreviation. J
JCT Junction Jkscr Jack screw JT joint(s) JW Jacket water J Piping, Plumbing Abbreviation. L
L Level L/MIN Liters Per Minute L/S Liters Per Second LA Level Alarm LAH Level Alarm-High LAL Level Alarm-Low LAT Leaving Air Temperature Lat Lateral LAV Lavatory Lb (s). # Pound (s) # symbol for pounds LBS Pounds LC Level Controller LC Lock Closed LG Level Gauge LG Level Glass Lg Length, long, level gauge LI Level Indicator LIC Level Indicating Controller Lin Ft Linear feet LJ Lap joint (flange) LLC Liquid level controller LLL Low Liquid Level LN Line LNG Liquid Natural Gas LO Lock Open LOL Latrolet LP Line pipe LP Low Pressure LPG Liquefied Petroleum Gas LPT Low Point LR Long Radius LR Level Recorder LRC Level Recording Controller LS Level Switch L Piping, Plumbing Abbreviation. M
M One thousand M Meter M&F Male and female (ends) MAT’L Materials MATL Material MAX Maximum MBH 1000 BTU/HOUR MC Mechanical Contractor MECH Mechanical MFD Mechanical flow diagram MFG Manufacturing Mfg Manufacturer MFR Manufacturer MG/L Milligram Per Liter MH Manhole MHT Male hose threads MI Malleable Iron MIN Minimum MIN Minute MIP Male pipe threads MIP Male Iron Pipe Misc Miscellaneous MISC Miscellaneous MK Piece Mark Mk Mark (spool piece) ML Milliter MM Millimeter MPT Male pipe threads MRR Materials receiving report MS MOP Sink MSS Manufacturers Standards Society of the Valve and Fittings Industry MTO Material take‐off (from drawings) MTR Mill Test Report MUV Automatic Make-UP Valve MW Miter weld MW Manway M Piping, Plumbing Abbreviation. N
N North N2 Nitrogen NC Normally Closed NDT Nondestructive Testing NEC National Electric Code NEG Negative NF Oil Free Dry (Nitrogen) NIC Not In Contract Nip Nipple (pipe) NIP Nipple NLL Normal Liquid Level NO Normally Open NO Number No or # Number NOM Nominal NOZZ Nozzle NPS Nominal Pipe Size NPSH Net Positive Suction Head NPT National Pipe Thread NTS Not to Scale NU Non‐upset (ends) N Piping, Plumbing Abbreviation. O
O2 Oxygen OA Outside Air OAL Overall Length OBD Opposed Blade Damper OC On Center OD Outside Diameter OEM Original equipment manufacturer OFD Overflow Drain OH Open Hearth OPP Opposite Orf Orifice OS&D Over short & damage (report) OS&Y Outside screw and yoke (valve) OS&Y Outside Screw and Yoke OSD Open Sight Drain OSD Open Site Drain OVHD Overhead OWS Oily Water Sewer OXY Oxygen Oz Ounce O Piping, Plumbing Abbreviation. P
P&ID Piping and instrumentation diagram PA Pipe Anchor PA Pressure Alarm PBE Plain both ends Pc Piece (mark for spool pieces) PC Pressure Controller PCV Pressure Control Valve Pdl Paddle (a blind plate between flanges) PdRC Pressure Differential Recording Controller PE Plain ends PE Plain End PI Pressure indicator (valves & gauge assembly) PI Point of Intersection PI Pressure Indicator PIC Pressure Indicating Controller PLE Plain large end PLE Plain Large End Plt Plat (steel) PO Pump Out PO # Purchase order number POC Point of connection POE Plain one end POE Plain One End POS Positive PP Polypropylene PP Personnel Protection Pr Pair PR Pressure regulator PR Pressure Recorder PRC Pressure Recording Controller Press Pressure PRV Pressure reducing valve PS Pipe support PS Pipe Support PSE Plain Small End PSE Plain small end psi Pounds per square inch PSI Pounds per Square Inch PSIA Pounds per Square Inch absolute psig Pounds‐force square inch, gauge PSIG Pounds per Square Inch Gage PSV Pressure safety (relief) valve PSV Pressure Safety Valve PT Point PTFE Polytetrafluoroethylene (aka Teflon) PVC Polyvinyl chloride PVF Pipe, valves and fittings PW Potable water P Piping, Plumbing Abbreviation. Q
Qty Quantity QUAD Quadrant QUAD Quadruple Q Piping, Plumbing Abbreviation. R
R Radius RA Return Air Rad Radius Rad Radians RCNP Reinforced Concrete Pipe RCP Radiant Ceiling Heating Panel RD Roof Drain REC’D Received Rec’d Received (materials) Recirc Recirculating Red Reducer RED Reducer REINF Reinforce REQ’D Required Req’d Required (materials) Reqn Requisition Reqn Requisition REV Revision REV Reverse RF Raised Face RG Return Grille RIV Roof Intake Vent RJ Ring Type Joint RO Reverse Osmosis RPM Revolutions per minute RPM Rotations Per Minute RPZ Reduced Pressure Backflow Preventer RR Red rubber (gasket type) RR Return Register RRV Roof Relief Vent RS Rising stem (valve) RS Rising Stem RTD Resistance Temperature Detectors RTE Reducing tee Rtg Rating RTJ Ring type joint (flange facing) RTRP Reinforced Thermosetting Resin Pipe R Piping, Plumbing Abbreviation. S
S Slip or Socket S South S/40 Schedule 40 (of pipe or fittings) S/80 Schedule 80 (of pipe or fittings) SC Sample connections Sch Schedule (of pipe or fittings) Scrd Screwed (ends) Sdl Saddle (pipe) SDR Standard dimension ratio SE Screwed ends SECT Section SH (SHT) Sheet SK Sink Skt Bld Skillet blind (plate between flanges) Smls Seamless spec SMLS Seamless SO Slip‐on (flange) SO Steam Out SOL Sockolet SP Set Point SP GR Specific Gravity SP/SPG Spigot SPEC Specification Spl Sht Spool sheet (from isometric drawing) Sq Square (inches, feet, yards etc.) SR Supply Register SR Short radius, stress relieve SRL Short radius ell SS Stainless steel STD Standard (a pipe or fitting schedule) STHX Shell and Tube Heat Exchanger Stl Steel Stm Steam Sub Short length of pipe or rod SUCT Suction SUPT Support SW Socket weld Swg Swage nipple SWP Safe working pressure SWP Standard Working Pressure SYS System S Piping, Plumbing Abbreviation. T
T Steam Trap T&C Thread and Coupled T&G Tongue and groove (flange facing) T/T Tangent to Tangent TA Temperature Alarm Tan Tangent TBE Thread Both Ends Tbg Tubing TC Temperature Controller TCV Temperature Control Valve TE Threaded End TEMP Temperature Thk Thick Thr’d Threaded THRD Thread TI Temperature indicator TIC Temperature Indicating Controller TLE Thread Large End TO Transfer Opening TOC Top of Concrete TOE Thread one end TOG Top of Grout TOL Threadolet TOS Top of Steel TP Trap Primer Line TPI Threads per inch TR Temperature Recorder TRC Temperature Recording Controller TSE Thread Small End TW Thermometer well TW Temperature Well TW Thermowell Typ Typical (repeat the same item) T Piping, Plumbing Abbreviation. U
UA Utility Air ULF Ultra low flush Un Union UR Urinal US Utility Station U Piping, Plumbing Abbreviation. V
VA Valve VA Vent to Atmosphere Vac Vacuum VAV Variable Air Volume VB Vortex Breaker VC Vitrified Clay VCP Vitrified Clay Volume VERT Vertical VF Vent to Flare VFD Variable Frequency Drive Vol Volume VS Vent to Stack VS Vent Stack VTR Vent Thru Roof V Piping, Plumbing Abbreviation. W
W West w/ With WB Welded Bonnet WB Wet BUB WC Water closet (toilet) Wd Width/wide WE Weld End WH Wall Hydrant WI Wrought iron WLD Weld WN Weld neck (flange) WOG Water / oil / gas (pressure rating) WOL Weldolet WP Working pressure WS Waste Stack WT Wall thickness/weight WT Weight W Piping, Plumbing Abbreviation. X
XH Extra heavy XR X‐ray (at pipe welds) XS Extra strong XXH Double extra heavy XXS Double extra strong X Piping, Plumbing Abbreviation. Y
Y Piping, Plumbing Abbreviation.
Piping, Plumbing Abbreviation