Thanks. What I have found so far from the API and NB is the onus is on the owner for developing their own plan based on the results from their own inspections.
Use an Initial Interval to start off with, then based on the results of the following inspections and testing/repair data; decrease interval by half for a Stuck-type failure [hard failure], decrease interval by 1/4 for 'soft' failures like chatter-requiring-lapping, failure-to-reseat, etc. Increase the interval by 1/4 to 1/2 the previous interval for each 'Test Only-no repairs required' result.
Clean process 3-years initial, 10-years max
Dirty process 1-year initial, 10-years max [includes steam]
Very Clean service* 5-year initial, 10-year max.
PRV protected by rupture disk 5-years initial, 10-years max
Rupture disks-Clean service 5-year interval, 5-year max
R/D's - Dirty service, 1-year initial, 5-year max
*nitrogen, dryed compressed air, hydrogen, chillers, methane/nat. gas, propane, etc.
Excellent & dilligent recordkeeping is a MUST for this program to actually work.
You may want to check with local utility companies operating electrical power plant as I remember that our region utility power co. was contracting hyraulic lift tests of their utility boiler safety valves on a periodic schedule, back in the 70's. I don't remember if the in-situ hydraulic test was annual, however their relieving capacity test was annual and shook up the entire region.
SRV's on Power boilers are tested based on State boiler laws within the US. It varies from 1 year to 3 years, depending on the local Jurisdiction requirements for operating certificates. Typically, valves are tested during internal boiler inspections. For pressure vessels, the frequency is every 3 years or longer to coincide with internal inspections for operating certificates. Some Jurisdictions do not regulate pressure vessels, In this case, the equipment insurer may have requirements.
