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Pipes and Equipment - Identification Labels

Tags and label colors used for mechanical, plumbing and piping systems.

Abbreviations, letter tags and label coloring for mechanical, plumbing and piping systems are based on

  • ASME A13.1 ‑ Scheme for the Identification of Piping Systems.
  • NFPA 99 – Standard for Health Care Facilities.
  • NFPA 13 – Installation of Sprinkler Systems.
  • NFPA 14 – Installation of standpipe and Hose Systems.
  • International Plumbing Code.
Pipes and Equipment - Identification Labels
Label AbbreviationSystem, Pipe ContentsLabel Colors
(Background - Text)
CHWR Chilled Water Return Green - White
CHWS Chilled Water Supply Green - White
CWR Condenser Water Return Green - White
CWS Condenser Water Supply Green - White
FOR Fuel Oil Return Yellow - Black
FOS Fuel Oil Supply Yellow - Black
HPC High Pressure Condensate Blue - White
HPS High Pressure Steam (above 125#) Blue - White
HWR Hot Water Heating Return Green - White
HWS Hot Water Heating Supply Green - White
LPC Low Pressure Condensate Blue - White
LPS Low Pressure Steam (below 25#) Blue - White
MPC Medium Pressure Condensate Blue - White
MPS Medium Pressure Steam
(above 25# - below 125#)
Blue - White
PCR Pumped Condensate Return Blue - White
ACID Acid Waste Orange - Black
BR Brine Water Orange - Black
FIRE Fire Suppression Water Red - White
HAZ Hazardous Waste Orange - Black
DI or RO High Purity Water Green - White
DCW Potable Cold Water Green - White
DHW Potable Hot Water Supply Green - White
DHWR Potable Hot Water Return Green - White
NG Natural Gas Yellow - Black
LN2 Nitrogen (liquid) Black - White
Med Air Medical air Yellow - Black
CO2 Carbon dioxide Gray - White
He Helium Brown - White
N2 Nitrogen Black - White
N2O Nitrous oxide Blue - White
O2 Oxygen Green - White
Med Vac Medical?surgical vacuum White - Black
WAGD Waste anesthetic gas disposal Violet - White
Lab Air Laboratory air Yellow and White checkerboard - Black
Lab Vac Laboratory vacuum White and Black checkerboard - Black boxed
IA Instrument air Red - White
CFHE Chemical Fume Hood Exhaust Purple - White
BCE Biosafety Cabinet Exhaust Purple - White
RE Radioisotope Exhaust Yellow - magenta
ETOE ETO Exhaust Purple - white

ASME A13.1 - 2007 Scheme for the Identification of Piping Systems - is intended to establish a common system to assist in identification of hazardous materials conveyed in piping systems and their hazards when released in the environment - concerns identification of contents of piping systems in industrial and power plants - recommended for the identification of piping systems used in commercial and institutional installations and in buildings used for public assembly.

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