I do a great deal of gas piping from about 1" and up. I seem to keep burning out air compressor. I use a small one with no tank. I would just like to know what some of you other plumbers out ther use and how do you feel about not using Mercury gauges for test?

I've taken to using dry nitrogen to air em' up. No more burnt compressors, trips to the gas station with the can, etc..

I had the hose shop make me up a hose with a chuck on it for about 4 bucks (my hose).

bout how long dose the dry nitrogen last how my feet and of what size? And what are you using to test Not a Mercury gauges. Thanks for the info I will have to look into that

Well, I'm residential only so 1-1/4" is usually as big as it gets, with maybe 30 or 40 ft runs at the most. I never really paid attention to how many I get out of a jug cause I do A/C linesets also. Maybe 5 or 6 jobs before I need to refill? Also depends on how many leaks of course.;> I use the smaller steel nitrogen bottle and not the big aluminum one. Bout 15 bucks a pop to refill. Dont forget to add it to the invoice!

I use a brass testblock 3/4, with a regular cheap guage on it. Like a water pressure guage but a 30 pounder.

Thanks alot for the info. Hope I can help you some day. Nitrogen will also show leaks right?

It might not show em at 15 pounds, but if the guage drops indicating a leak, go pump it up to 100 -150 and you'll hear the leak.

If you leave the gauge on overnight or in the sun the resultin temp change will show a pressure change on the guage, lower for cold conditions and higher for hot conditions, but these are not leaks



Post Edited (06-21-03 13:09)

We test gas pipe at 5 p.s.i. Usually gas is about 14" w.c. 150 p.s.i. is insane unless it's welded pipe. For residential, a lot of guys put the pipe together with 2 pair of channel locks.

Test pressure for us is 15 lbs, but looking for small leaks with 5 or even 15 lbs of pressure is a little bit overboard time consuming. 100 to 150 lbs will tell you where your leak is in a hurry. Black steel pipe has no problem holding more pressure than that, unless of course some guy put it together with two pr channellocks! You can get away with channellocks on 1/2" only, but 3/4" asks for two 14" pipewrenches, 1" asks for 18's, 1--1/4" asks for a 24 & 18, and so forth.

I've fixed a lot of them two pr channellocks guys callbacks.

Heck, test pressure used to be 100# / 24 hrs! Then they went to 5# for awhile, now their back up to 15# / 15 mins.

Our test is 10 psi using a gauge with ounce increments/divisions.

I don't put gas pipe together with 2 pair of channellocks, I know bungalow busters that do it, though. They don't get many leaks, if they do, they're down the road.

I start all my pipe (smaller then 2" with channellocks like a 16" pair with a pipe grove then use 2 18" Aluminum pipe wrench. to drive them home. what type of dope you guys use? Here "New York" we use alot of ProDope on gas.

what type of dope you guys use?

Lessee, crack, meth, weed...No seriously, I use either The white teflon stuff or the blue Megaloc stuff. That magaloc is good stuff.

I hate that yellow runny Rectorseal stuff. Its a callback waiting to happen, dont trust it.

Most plumbers that I know use the megaloc or slik-tite. Most pipefitters use the rectorseal. I think it is a matter of what your shop provides, then the guys get used to it. Plumbers like the megaloc because it can be used on pvc and compression fittings(angle stops) as well. I like the grey pro-dope for gas pipe, but you can't use it on pvc, so I don't bother with it anymore.

I use Pro-dope on gas white teflon past on water and drains some times on boiler with lamp wick (old school)or blue block on boiler and spricks(fire)teflon tape with air. Have you guys seen the gas dope with lead or some thing in it? A steamfitter I know was talking about it. Just wanted to if any of tryed it.