When Does a Relief Valve’s Clock Start?


While it is well known that good engineering practice requires that relief valves be replaced every five years, industry literature does not clearly state when the five-year timer starts its countdown. Is it when the valve is manufactured? Taken out of the box? Installed? Exposed to ammonia?

Due to the lack of clarification on this topic, the International Institute of Ammonia Refrigeration (IIAR) Standards Committee answered this exact question on March 10, 2017. The full text of their response is available on their website and included below for quick reference:

Interpretation IIAR SC 2016-01

Question: Does the 5-year replacement interval begin upon: a) Installation of equipment b) Charging the system with refrigerant or c) Start-up of the system?

Answer: The IIAR Standards Committee has considered the topic of shelf life. The committee’s conclusion was that the replacement interval shall start on the day that the SRV is installed onto the system, regardless of how long it has been stored.

It is incumbent upon the installer to visually inspect SRVs before installation. Any visual deterioration (such as surface rust) would be cause to reject the SRV. Facilities should have a procedure in place such that a visual inspection is made before installing SRVs. Further, if it is the practice of facilities to stockpile SRVs, their procedures should indicate that they are stored in an appropriate area, with appropriate protection.

It is important to note that the inspection and storage recommendations are not part of this interpretation.


5 responses to “When Does a Relief Valve’s Clock Start?”

  1. Danny says:

    This was helpful but the link to the document on the IIAR website no longer works and I can’t seem to find it on the IIAR website. Can anyone tell me where to look? Thanks in advance.

  2. James Gray says:

    If a relief valve has been sitting on the self and the tag no longer can be punched to the current year is it legal to replace the tag. If it is legal what is it to prevent from just replacing a tag and not a valve that has been in use.

    • Peter Thomas says:

      It is acceptable to remove the tag and put a new tag on. In fact there is no requirement (that I am aware of) that the valves have a punched installation date tag (but I do recommend it). The bottom line is that the clock starts when the valve is put into service. Replacing an installation date tag on a valve that has been in service for more than five (5) years would likely be viewed as a willful citation and subject to heavy penalties (or worse).

      I don’t recommend keeping relief valves on the shelf for years in order to avoid this type of situation. However, if you have a valve that has been stored for 5+ years, there is nothing preventing you from installing it.

Leave a Reply

Your email address will not be published. Required fields are marked *