[kb13]

My plumber told me that it is normal for a galvanized gas line to leak down preasure over time. I have noticed that there are only 15 minute test, Why is it OK for it to leak past 15 minutes?

[letmetellu]

If you put a fifteen minute test on a gas line you should not have any leak at all for a safe gas system. Some gas suppliers might give you a very small leeway but that is not the norm, most want it with no leaks at all.

[Fr_Chuck]

This is not normal or acceptable for gas lines. This is like saying ( actually worst since it is gas) well the waterline in your ceiling is only leaking a small amout of water so don't worry about it.

[speedball1]

My plumber told me that it is normal for a galvanized gas line to leak down preasure over time. I have noticed that there are only 15 minute test, Why is it ok for it to leak past 15 minutes?

Your incompetent plumber should have told you that black iron pipe is used for gas piping. Galvanized flakes off and clogs the orifice in the burner.
Also** ANY LEAK IN A GAS LINE IS DANGEROUS AND UNACCEPTABLE!
Can the plumber and get one in with plumbing smarts. Good luck, Tom

[iamgrowler]

Your incompetent plumber should have told you that black iron pipe is used for gas piping. Galvanized flakes off and clogs the orifice in the burner.

Hold the phone here, Tom -- Plumbing something to code in ones jurisdiction does not make one "incompetent".

There are a number of applications where code requires the use of galvanized pipe for natural gas piping -- Particularly when the piping passes through masonary or is being used for below ground burial.

Black iron is always preferable to galvanized, but you aren't allowed to bury unwrapped black iron and you are never allowed to install black iron in situations where it may be in contact with masonary products.

Machine wrapped black iron is allowed for direct burial under all of the prevailing codes, but machine wrapped black iron isn't available in about 90% of the country, and the codes specify machine wrapped as a means of distinguishing it from hand wrapped, which is most definitely not allowed except for the portions of pipe stripped for threading and for fittings.

You might say; 'Well, why not use copper tubing and flared brass fittings?"

To which I would say; "Copper tubing is banned for the delivery of natural gas in areas where the UPC is the prevailing code and in municipalities covered by the IPC and the SPC where the local authority has deemed the soil to be too alkaline."

As for the pitfalls faced by using galvanized piping you mention -- There is no doubt the zinc coating will flake off over time, but there are ways to run the piping that can reduce the effects of this flaking on the appliances being fed.

Vertical transitions from horizontal where accessible can be fitted with tee's and drip legs that will trap the flaked off pieces -- And getting into the habit of always dropping down from above the appliance so that the last 8 or 9 feet of the run is vertical with a tee and drip leg will also go a long way towards alleviating the problems associated with debris in the piping system.

As for drip legs, there is a common misconception as to the reasons for their use.

You likely already know this, but drip legs aren't just for collecting condensation in the lines, which is really only common in areas where the natural gas being delivered is derived by cracking it from coal, which is generally a region specific issue -- Drip legs are also intended to catch debris entering the lines from the fuels source (the utility providing the gas), excess cutting oil left in the pipe during the threading process, debris introduced into the piping during the installation process and any debris caused by the aging of the system.

also** ANY LEAK IN A GAS LINE IS DANGEROUS AND UNACCEPTABLE!
Can the plumber and get one in with plumbing smarts. Good luck, Tom

I agree with this part -- Any Plumber willing to plumb only to the bare minimum requirement on something as fraught with danger as gas piping ought to be canned.

Period.

To the OP; If my gas piping won't hold 15lbs of air for at least 24 hours, then I pump the system up to 30lbs and spray every joint with soapy water until I find the leak -- I then back the piping out to that point and start all over from that point.

We don't run as much gas piping as we used to, but we always capped the pipe off before breaks and lunch and tested the portion already run before continuing with the rest of the installation.

[speedball1]

Thanks Growler,
We don't don't do much gas piping here either. The last time I piped gas I roughed in a strip mall with a bakery. I used type "K" copper with flared joints, and that was many years ago. I don't ever recall putting in a gas hot water heater in my area. Everyone uses electricity. However at the time I was out in the field black iron pipe and copper were all were allowed for gas in my area.
I was not aware that galvanized was acceptable and I thank you for the correction and the information. That's why you top experts are so valuable to the plumbing page, and I still say the plumber was imcompetent for giving his customer faulty and dangerous advice concerning the leakage test. Regards, tom