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Ammonia Pipe Labeling Chart

Ammonia Pipe Marking

International Institute for Ammonia Refrigeration (IIAR) Pipe Marking Guide

The International Institute of Ammonia Refrigeration (IIAR) has published bulletin #114, which is called "Guidelines for Identification of Ammonia Refrigeration Piping and System Components," to provide a standard system for ammonia pipe labeling. When labeling pipes containing ammonia, the ammonia pipe markers should contain the elements shown in the figure below.

ammonia piping identification

LIQ - Orange color band indicates liquid state

VAP - blue color band indicates vapor state

Use both color bands if both liquid and vapor may be present.

High - Red color band indicates high pressure

Low - Green color band indicates low pressure

  1. Use arrows at both ends to indicate the direction of ammonia flow in the pipe.
  2. Use the abbreviations shown in the table to identify system components.
  3. Indicate whether the refrigerant is a liquid, vapor or both.
  4. LIQ-Use black or white text on an orange color band for liquid ammonia.
  5. VAP-Use black or white text on a blue color band for ammonia vapor.
  6. LIQ/VAP-Use both color bands if both states may be present.
  7. Print AMMONIA in black letters on a yellow background.
  8. Indicate whether the internal pipe pressure is high or low:
  9. HIGH pressure: Use black or white text on a red color band.
  10. LOW pressure: Use black or white text on a green color band.

System Component Abbreviations

BD Booster Discharge CD Condenser
DS Defrost Condensate ES Economizer Suction
HGD Hot Gas Defrost HPL High Pressure Liquid
HSD High Stage Discharge HSS High Stage Suction
HTRL High Temperature Recirculated Liquid HTRS High Temperature Recirculated Suction
LIC Liquid Injection Cooling LSS Low Stage Suction
LTRL Low Temperature Recirculated Liquid LTRS Low Temperature Recirculated Suction
RV Relief Vent TSR Thermosyphon Return
TSS Thermosyphon Supply

This ammonia pipe marking guide is intended for general information purposes only. This guide is not a substitute for review of applicable government regulations and standards.

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