Gas PSI

y0manda

Building a detached garage, customer wants washer/water heater & Dryer in there. Just installed the gas line. I used 3/4 black iron with green coating @ 20" deep. Applied Primer on all fittings and 40mil tape. the Run was about 70 linear feet connecting from existing 3/4 black pipe under house where the old water heater was. Turned on the gas @ the meter & the pressure valve in the garage didnt show any PSI. It is a gas pressure check valve that goes upto 14 PSI with a valve stem on it. There is gas coming out of the pipe in the garage and the meter *really old* can hear gas flowing when the pressure check valve was off.
My questions are:
How much PSI of gas should I be reading?
Is the valve stem on the pressure check valve for adding air with a compressor to see if it holds the same PSI over a period of time?
Could it be the older main gas meter restricting gas for the house?

Thanks in advance.
Mike.

KillerToiletSpider

Natural gas is .5 PSI on a non high pressure system.

__________________
A flush is better than a full house.

y0manda

Thanks KillerToiletSpi
Regarding the air valve stem on the gauge is that for adding air to see if it holds the same amount of PSI over a lengthy period? Will the city inspector want to see a reading on the gauge?
Mike

KillerToiletSpider

Most inspectors won't check gas pipe, but showing it on a gauge won't hurt.

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A flush is better than a full house.

JamesNLA

Huh???

News to me....

To the OP, did you do any calculations to determin if adding a 70 LF branch will deliver the proper Water Column to your appliances? Account for pressure drops?

It sounds like you have some experience in putting gas lines in....although I only use 20 mill tape, but primering your fittings is correct. 70 feet and you only ran a 3/4" line? That's crazy. What I find that inspectors won't do is your calculations for the WC but they sure as hell do inspect new gas lines...at least in my area, don't really know about other states.

70 feet with 3/4"......

Did you also say that you had a pressure gauge on your new line, attempting to get a reading? Most pressure gauges are more for lbs...like up to 200 PSI. If your goes that high, don't expect to see a 1/2 pound.

And the bicycle style inlet is to add / remove air after a pressure check. I go to 50 lbs, I think code says 10 or 15 minutes. Ron the Plumber wrote up a detail on that not too long ago.

So I gotta question, what happends when the HO wants to put a Gas tankless water heater out in the garage?

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thom

In my jurisdiction gas is always permitted and inspected. We would have an inspection prior to burial to make sure the coating wasn't damaged and the joints were properly taped. The inspector would question the pipe size and ask for your calculations. We would have a second inspection (final) that's a pressure check. Pressure must maintain 10# for 20 minutes with NO drop. After passing the test the line can be filled with gas.

Grumpyplumber

I guess things are VERY different from one state to another, the idea that gas lines could be done with minimal inspection or without a license is bizarre.
Also, low pressure gas is rated at a max psi of .5 psi, but usually runs at about .25 psi or 7.5-8 inches water column.

Ron The Plumber

UPC code is test at 15 psi for 15 min. New gas lines are always inspected.

Use of pressure gauges are determined by the psi you will test at, it should be no more then twice the psi the test is required at.

15 psi = 30 psi gauge

crb555

You cannot really use a psi gauge to accurately measure the psi on a gas line that is in service. That is only for when you test with compressed air or something.

To measure pressure in a gas line, get a manometer. You should be somewhere between 7 - 11 " W.C.

Crb5

MechanicalDVR

In my area to get the permit you need to submit a piping diagram showing the whole gas piping layout with btu loads and your calculated pipe sizes. The test is 15 / 15 on a 30# as Ron quoted. We go by National Fuel Gas Code. Thinking of gas in terms of psig is scary. We use less than 8 iwc in this area, sometimes it's hard to get 5 in winter.

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crb555

We have the same test requirements here. 15#/15min.
We do not have to submit any sized drawings, I will say that the GA plumbing test has a large portion devoted to gas load calculation and pipe sizing.

OTOH, I have definitely come across incorrectly sized existing lines, so that probably wouldn't be a bad idea, if it weren't for the fact that I am certain that our local officials do not have the capability to do any better of a job.

Crb

y0manda

cloths dryer uses approx 35,000 BTU = 31.81 cubic feet / hr
Water Heater uses approx 50,000 BTU = 45.45 cubic feet / hr
Total Gas to be used in the garage is 77.26 cubic feet / hr

A total distance from Gas meter to garage on a 3/4" pipe no longer than 100 LN will deliver 103 Cubic Feet/Hr
Does this seem to be fine?

I appreciate all the comments made.

Mike

Grumpyplumber

Yomanda, as a GC don't you have a regular plumber you use?
I have several GC's that give me regular business, when they call for help and they're tight on a job I'm happy to accomodate for all the work they give me...when it's safe.

y0manda

I do know a few plumbers but they all seem to be impossible to get in touch with. I even tried to call a few from the blue book and no call backs, I needed to get this gas line in the stem wall ASAP before footing inspection. This is about as complex as I would go with running a gas line myself, anything more I wouldn't touch. BTW the 40mil tape is 20 mil doubled which is required for Riverside, CA.

y0manda

Grumpyplumber

You have permits pulled I assume.
When the building inspector see's your work there's a strong chance he'll see the gas work..there would be questions.
In my state the building, electrical and plumbing inspectors literally sit together, you might be painting yourself into a corner.
If I get a call from someone to redo unlicensed work, it's more expensive than it would have been from the start, I'll wager any other plumber here will agree.

Grumpyplumber

Also, let me know what area you're in...strong chance I could find you a plumber.

y0manda

I am from Riverside, California.

Grumpyplumber

Apologies, went on vacation.
I know of 2 plumbers from Cali, unfortunately the closest is 1-1/2 hours from you.
Invest a half hour and leave messages on voice mails, it might take a day or two, but you'll get replies.