I’m in the process of installing a gas line from our house to a detached garage (about 15′ of run). The line is currently in a 20″ deep trench and enclosed in a vented sch. 40 PVC conduit. I have installed a gas test gauge on the line and pumped it up to 20 psi. What is the allowable limit (if any) for pressure loss? Over what period of time? And, most important, is there any allowance for pressure fluctuation due to temperature changes? Thanks in advance, Jim Finley
There is no loss allowed. The pressure for underground gas piping, and its sleeve, is usually 60 pounds. Since the inspector will be there for only about 15 minutes fluctuation should not be a problem.
NO LOSS is allowed NYC building code wants a test of 6″ (3 PSI) mercury for 1 hr The Gas supplier (utility)wants a test of 200 PSI for 2 hours. Depending on local codes what pressure test you need to perform and the duration.In my area for example any gas pressure exceeding 1/2 PSI is considered high pressure. Contact your local inspector…Good luck