CORRECTION Made 3/21/2018
So I was glad I was sitting down when I started reading the Public Review #2 Draft of IIAR-6, Standard for Inspection, Testing, and Maintenance of Closed-Circuit Ammonia Refrigeration Systems. Now it’s just a DRAFT version out for public review and comments, but I was so pleased to see TABLE 13.1, Overpressure Protection Devices Inspection, Testing, and Maintenance Tasks state:
“5 and a representative sample replaced and tested annually until bench testing results determine a failure.”
and
c) Bench tested pressure relief valve (PRV) replacement – As determined from bench testing results of a representative sample
Back in September 2014 I wrote a post, Bench Testing your Relief Valves and IIAR, and around the same time IIAR brought up the topic and made their business case for “bench testing” a sampling of RV’s each time to establish an actual data-based frequency rather than using the “at least every five years”. The PUBLIC DRAFT even provides some excellent guidance on how this testing program should be managed. But it is not what it appears!
13.1.1 Where pressure relief devices discharge to a water diffusion tank, the water level and condition of the water shall be maintained.
13.1.2 *Where the owner or owner’s designated representative elects to replace pressure relief valves (PRV’s) as an alternative to the prescriptive 5-year replacement interval from the Installation Date, the following shall occur:
(SAFTENG Correction: so IIAR does NOT require bench testing of RV’s when the facility chooses to follow the prescriptive 5-year replacement interval; ONLY when the facility would like to extend the frequency beyond 5-years, will they need to follow 13.1.2.1 below. Thanks to all of the IIAR attendees who contacted me regarding this error. I guess a man can dream and have hopes that one day, maybe one-day IIAR will require testing of the RVs to validate the 5-year frequency.)
13.1.2.1 After 5 years of service from the Installation Date, a representative sample of pressure relief valves shall be removed from service and bench tested to confirm the rated flow rate at the nameplate set pressure is established while verifying the pressure relief valve actuates at plus or minus (+/-) 3% of the set pressure and is fully open by 110% of the set pressure.
13.1.2.1.1 Where 100% of the tested pressure relief valves pass the bench test, the remaining installed pressure relief valves are permitted to continue in service for an additional twelve (12) months before the next representative sample of pressure relief valves are removed, and bench tested.
13.1.2.1.2 Where any tested pressure relief valve fails the bench test, all installed pressure relief valves that have been in service for a period equal to or greater than the failed pressure relief valve shall be replaced within six months.
13.1.2.2 The representative sample shall be no less than seven pressure relief valves or 5% of the total number of pressure relief valves installed on the system, whichever is greater.
13.1.2.3 Each representative sample pressure relief valve shall have an established life that is not less than any other installed pressure relief valve installed on the system.
13.1.2.4 Each representative sample pressure relief valve test result shall be recorded.
13.1.2.5 All pressure relief valves shall be replaced at a time interval that is not greater than the shortest service life of a pressure relief valve that did fail the bench test.
13.1.2.6 The test results shall be used to justify the frequency for the alternative method for pressure relief valve replacement.
13.1.2.7 A pressure relief valve that has passed the bench test shall be recertified by a qualified facility before it is placed back into service.
But reality sets in and the “bench testing” is merely an alternative to the 5-year “change out” frequency; so essentially, the ammonia refrigeration industry will still allow a business to run their RV’s without any validation for a 5-year period, take them off and throw them away and buy a new RV in place. Oh so close! See my highlights above.