The purpose of a pretest is to determine if a Pressure Relief Valve (PRV) would have operated on demand within the set pressure tolerance limits of the code for the entire period it was in service.
What are pretest test results used for?
They are used to:
- create history;
- adjust the servicing and/or testing intervals of the PRVs;
- take corrective action, as necessary, to assure proper performance of the
PRV (other than adjusting the service interval). For example, if a PRV did not operate within the set pressure tolerance limits or was found to be stuck closed due to corrosion products, a corrective action may be to install a rupture disc at the inlet or outlet, as the case may be, to prevent corrosion of the PRV’s internals or replace the PRV with the one whose materials will not corrode or reduce the corrosiveness of the process.