Natural Gas line - pressure test


  #1  
Old 02-20-08, 01:24 PM
B
Member
Thread Starter
Join Date: Dec 2004
Location: California
Posts: 33
Upvotes: 0
Received 0 Upvotes on 0 Posts
Natural Gas line - pressure test

I've replaced a length (14') of gas pipe with "black" gas pipe.

Gas is on and passed the soap bubble test.

I also want to do the air pressure test.

Is this the procedure:

1) Gas off
2) Disconnect meter from incoming gas line
3) Connect gas pressure gauge to incoming gas line
4) Close all valves that preceed appliances (range, oven, WH, Furnace, Clothes dryer)
5) Add 10 lbs air pressure at the pressure gauge
6) Wait 6 hours - check results
7) If pressure is less than 10 lbs - repressurize and soap test.

I have also read that the appliance(s) should be disconnected before the test. Is this to protect the appliance in the event the inline valve fails?
 
  #2  
Old 02-20-08, 08:05 PM
Terd Herder's Avatar
Member
Join Date: Jan 2008
Location: Northern Illinois
Posts: 277
Upvotes: 0
Received 0 Upvotes on 0 Posts
All in the list sound good. Personally, I would just soap test, then do it again in a couple hours. Give it some time to push any dope or tape out. Whatever you feel comfortable with. Good job!
 
  #3  
Old 02-21-08, 02:49 AM
H
Member
Join Date: Jul 2005
Location: New York
Posts: 657
Upvotes: 0
Received 0 Upvotes on 0 Posts
That is the procedure for pressure testing new gas line, however, the time and pressure varies depending on the AHJ.

It not a bad idea to disconnect the appliances when testing in the event of a valve failure. Additionally, there are many styles of valves out there. Don't use a 5 psi rated valve when testing @ 10 psi.
 
  #4  
Old 03-30-09, 10:05 AM
P
Member
Join Date: Nov 2007
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Is there anypoint is going to 100 psi when performing a new line test? Or will there be more of a chance of leakage...
 
  #5  
Old 03-30-09, 11:21 AM
plumbermandan's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jan 2009
Location: Texas
Posts: 837
Upvotes: 0
Received 0 Upvotes on 0 Posts
there is no point since the gas pressure to your house should not be more than 2psi unless you have a red faced meter, at least in my area.

but whenever making any repairs and definately adding (since adding should entail a permit and inspection) testing the whole system is a very good idea.

there have been a lot of gas explosions the last few years. gas is the one thing that does not allow even 1 mistake when installing it.
 
  #6  
Old 03-30-09, 07:51 PM
Z
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 6,095
Received 422 Upvotes on 375 Posts
Originally Posted by Terd Herder
Personally, I would just soap test, then do it again in a couple hours. Give it some time to push any dope or tape out. Whatever you feel comfortable with. Good job!
I have to disagree with this comment... from personal experience. I recently moved a gas dryer across the basement. Did all my piping, tightening nice and tightly. Turned on the gas and soap tested everything... perfect job!

Inspector came by, said it all looked good but needed to be pressurized to 15psi and he'd come back and look at it. Went ahead and purchased the gauge, filled it with 15psi... and the 60' or so lost all pressure within about 5 minutes. Took about 8 hours of tightening, disassembling, and retightening to pass the pressure test.

Lesson learned... just because soap bubbles don't form at the ~2psi of gas pressure doesn't mean it's not leaking!
 
  #7  
Old 03-31-09, 08:17 AM
plumbermandan's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jan 2009
Location: Texas
Posts: 837
Upvotes: 0
Received 0 Upvotes on 0 Posts
actually you may not even have had 2psi on it with just the gas on, that would be a maximum it would be. but it is to be tested to 1.5 times the working pressure by most codes and who is to say which working pressure since the gas company may be running 5-60 psi. but 15 is the norm for a high pressure sure line thus the requirement for 15 psi test. your line would probably have never leaked with just normal gas pressure.

remember gas is the one thing that doesnt allow for mistakes and so you can never be to safe with the installing/repairing of gas systems. pressure testing must be done to ensure it is as safe as possible.

you would not believe how many older lines have slow leaks that have developed over the years and that the smell disapates before getting to where someone can smell it until its to late. for almost every gas explosion someone is reported to have said they smelled gas but no one ever bothers to call anyone until something has actually blown up
 
  #8  
Old 09-09-10, 05:14 PM
M
Member
Join Date: Sep 2010
Location: usa
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
pressurizing with air

I know this is an old thread, and I am going to come off as a dumb blonde but in all I've researched on testing gas lines with air the part I want to know is missing. What on earth do use to hook up your air hose to your 1" black iron pipe? It has all said, "Hook up your (compressor) to your line and pressurize." ???!!!

I have a Shrader type valve on the end of a normal air compressor hose to connect with a 1 inch new empty stubbed out & capped black iron pipe (male). Any help? Or did I miss it? Thank you, L
 
  #9  
Old 09-10-10, 12:04 AM
steve_gro's Avatar
Member
Join Date: Jan 2004
Location: San Francisco
Posts: 967
Upvotes: 0
Received 1 Upvote on 1 Post
You can buy a 1/4" IPS x schrader (tire valve) fitting and a 1" x 1/4" IPS reducer and screw that on to your 1" pipe.

Amazon.com: Air Intake Valve: Home Improvement
 
  #10  
Old 09-12-10, 07:14 AM
Z
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 6,095
Received 422 Upvotes on 375 Posts
I'd recommend something like this:

Larsen Supply Co 13-1891 15PSI Gas Test Gauge - Plumbing & Heating - Septic Tank & Cesspool Equipment - Pressure Gauges

It provides both the pressure gauge as well as the schrader valve all in one!
 
  #11  
Old 09-14-10, 05:07 PM
N
Member
Join Date: Sep 2010
Location: u.s.
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
I have just changed over from propane to ng. the plumber put 3psi in the line and came back the next day (after the inspector) and pressure was @ 2.5 psi, he said it was normal for a system to lose 1/2 lb over 24 hrs. IS this normal? or is he just blowing me off?
 
  #12  
Old 09-14-10, 07:17 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 38 Upvotes on 30 Posts
Depending on the temperatures when he pumped it up to 3 psi and then later when the gauge read 2.5 psi it could entirely normal. If he pumped it around noon to maybe four in the afternoon and then the ambient temperature dropped 10 or 20 degrees overnight and the gauge read 2.5 psi the next morning it was definitely normal.
 
  #13  
Old 09-15-10, 02:32 AM
N
Member
Join Date: Sep 2010
Location: u.s.
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by furd
Depending on the temperatures when he pumped it up to 3 psi and then later when the gauge read 2.5 psi it could entirely normal. If he pumped it around noon to maybe four in the afternoon and then the ambient temperature dropped 10 or 20 degrees overnight and the gauge read 2.5 psi the next morning it was definitely normal.
Thank You Furd !! it was tested Aug. 19th and the temperature hit 90 that day. you gave me some "peace of mind" back.
thanks again.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: