ips gas test

bob young

any new techniques on testing gas malleable  fittings other than soap bubbles. any one ever try black swan leak detector ? if so is it worthwhile or are results similiar. for a working pressure of 1/2 "  , what is recommended test pressure is test pressure is 3 # . if you pumped line to say 30 #  would it affect the integrity of the existing threaded joints. bob nyc lic. plbr.

Bob Harper

gas pressure testing

The IRC calls for testing at min. 1.5 times the max. working pressure but no less than 3 psig. So, if your max. is 1/2 psi, you test at 3 psi x 10 min. The test gauge must be no greater than 5 times the test pressure. If you test at 3 psi but use a gauge that reads to 30 psi, that would be illegal. If you test at 30 psi your gauge may not read higher than 150 psi. Now, let's say you have a tiny gas leak. Which do you think will show the leak: the 15 psi gauge at 3 psi or a 150 psi gauge at 30psi? Remember, you are looking for any movement in the needle. Parallax error alone can fool you in reading a minor deflection or not. You want the lowest gauge you can so that the slightest movement of the needle will indicate a leak. All this high pressure testing is asinine. Yes, some fittings can be compromised by higher pressures. For instance, some shutoffs are rated for only 3 or 5 psi. Now, they may have been tested to 125psi burst but that does not mean the can't leak. I can assure you that those brass "key' valves located in the floor or wall for gas logs in fireplaces WILL leak if tested >3psi except for the newer ball valve types.



When selecting a soap bubble test solution, look for one that is non-corrosive. Otherwise, you definitely have to rise it off. Otherwise, you can cause stress cracking in the base metal and cause a leak later. For very tiny leaks, try a thin-film solution. Larger leaks will blow these bubbles away so you may need a higher viscosity solution to demonstrate these leaks. That means at least two types of solutions. Also, the colder it gets the thicker they all get. Allow sufficient time for a bubble to form.



Trace gas leakage can be demonstrated by a "Bubble-O-Meter" such as used in lab testing. You can use a simple manometer to test if an appliance valve or MP regulator is holding or creeping.



HTH

bob young

ips gas test

THANX, BOB.  Needed another opinion from a fresh pair of eyes. yours was probably as good as it gets. very well thought out & precise. thanks again. bob young