Labeling an Ammonia Receiver


Question: What are the labeling requirements for a High Pressure Receiver in an ammonia refrigeration system?

Answer: To properly label any piece of equipment within an ammonia refrigeration system you  must first know which codes and standards are recognized in your jurisdiction. As a resident of California, the following codes/standards are often consulted regarding ammonia equipment labeling:

  • California Mechanical Code
  • California Fire Code
  • IIAR Bulletin No. 109 and No. 114

2013 CMC §1123.2

A condenser, receiver, absorber, accumulator, and similar equipment having an internal volume of more than 3 cubic feet (0.1 m3) and containing refrigerant shall be equipped with a permanent label setting forth the type of refrigerant in such vessel.

2013 CFC §606.7

Refrigeration units or systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A 1 or 30 pounds (14 kg) of any other group refrigerant shall be provided with approved emergency signs, charts and labels in accordance with NFPA 704. Hazard signs shall be in accordance with the California Mechanical Code for the classification of refrigerants listed therein.

[Note: The proper NFPA 704 designation for ammonia is 3-3-0 when installed indoors, and 3-1-0 when installed outdoors. you can read more about NFPA 704 for ammonia here.]

IIAR Bulletin No. 109 §4.3.7

All heat exchangers and pressure vessels should be identified with a component marker that identifies the particular component. The marker should also provide information regarding the operating temperature or pressure of the component as described in IIAR Bulletin 114, “Guidelines for: Identification of Ammonia Refrigeration Piping and System Components”.

IIAR Bulletin No. 114 (March 2014) §4.2 Component Markers

Component markers will bear the name of the equipment they identify, e.g., RECEIVER, ACCUMULATOR, RECIRCULATOR, etc. In addition, component markers will be provided with a pressure level designation. Additionally, other information can be provided.

Component markers will have BLACK letters on a SAFETY ORANGE field.

Pressure Level will be indicated by the word HIGH in RED letters or the word LOW in GREEN letters printed or applied flush with the right edge of the marker.

[Note: Prior to March 2014, IIAR Bulletin No. 114 recommended SAFETY YELLOW as the background color for component markers.]

Now that we’ve identified the codes and standards that apply to ammonia equipment, we can summarize the requirements for compliant high pressure receiver labeling:

  1. NFPA 704 placard utilizing the 3-3-0 designation if located indoors, or the 3-1-0 designation if located outdoors (2013 CFC §606.7).
  2. Component name in BLACK letters on a SAFETY ORANGE background with the relative pressure level (HIGH) on the right edge of the marker (IIAR Bulletin No. 114 §4.2).
  3. Indication that the vessel contains ammonia (2013 CMC §1123.2). [Note: the argument can be made, that completing #1 and #2 provides clear indication that the vessel contains ammonia]


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