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Kitchen44739  
#1 Posted : 22 May 2014 09:51:55(UTC)
Rank: New forum user
Kitchen44739

Good Morning, I was hoping someone would be able to offer me some specialist advice relating to Pressure Systems. Would anyone be able to clarify if the Pressure Relief Valves on an Ammonia Plant need changing every 5 years. I have researched the Pressure Systems Safety Regulations 2000 ACOP and understand that a Written Scheme of Examination is required, but I could not see a specific requirement for replacing the valves every 5 years. Can anyone help? Many Thanks in advance
PIKEMAN  
#2 Posted : 22 May 2014 10:03:47(UTC)
Rank: Super forum user
PIKEMAN

I know of no such requirement, as you say you need to follow your SOE. Try asking the manufacturers - there may be a good reason for the 5 year change, or not!
JJ Prendergast  
#3 Posted : 22 May 2014 11:24:10(UTC)
Rank: Super forum user
JJ Prendergast

Try and find out what (British??) standard it is manufactured too - then check what the standard calls for. There may (also) be a suitable API standard to work to. The valve might simply need removing, servicing and rig testing/checking. The PSSR won't/doesn't give specific time requirements for valve replacement/removal - PSSR is generic legislation, puting into law the required engineering practices for pressure safety management. The detail you want will be in a recognised engineering standard. The 'life' of a valve can depend on a number of factors.
jontyjohnston  
#4 Posted : 22 May 2014 15:17:15(UTC)
Rank: Super forum user
jontyjohnston

Agree with the above posts. Used to look after ammonia reactors, the scheme of inspection should be such that it accounts for the operating variables of the plant / apparatus - in you case the PRV's. Ammonia can be hard on plant (!) so scheme of inspection might require more frequent inspection than sat a PRV on an air compressor. The engineering inspection will tell you when to replace the valve based on the condition assessment. J
jay  
#5 Posted : 22 May 2014 16:23:24(UTC)
Rank: Super forum user
jay

Apparenmtly, The International Institute of Ammonia Refrigeration (IIAR), in its Bulletin 109, IIAR Minimum Safety Criteria for a Safe Ammonia Refrigeration System, recommends that the relief valve be replaced or inspected, cleaned, and tested every five years. ANSI STD K61.1-1989, Safety Requirements for the Storage and Handling of Anhydrous Ammonia, is very specific in its requirements. Paragraph 6.8.15 states: “No container pressure relief devices shall be used after the replacement date as specified by the manufacturer of the device. If no date is specified, a pressure relief valve shall be replaced no later than five years following the date of its manufacture.” In industrial refrigeration, the current recommendation is to replace the relief valve on a five-year cycle. Be sure to check with other agencies to verify that a more stringent regulation is not applicable. ANSI/IIAR Standard 3-2012---American National Standard for Ammonia Refrigeration Valves
JJ Prendergast  
#6 Posted : 22 May 2014 16:37:25(UTC)
Rank: Super forum user
JJ Prendergast

No doubt good information from Jay. However, if you can find the specific standard that your PRV is manufactured to - then I would recommend that you follow that standard, instead of 'mixing' standards that you comply with. The manufacturing/design standard you have, may also say 5yrs, so nothing lost in practice. Splitting hairs maybe, just think it would be better practice to work to the standard applicable to your PRV.
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