Gas pipes - best practices

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Old 01-08-08, 06:14 AM
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Gas pipes - best practices

Hello All...my first post.
I'm looking for recommendations regarding sealants for gas pipe. Also, is there a rule of thumb for how tight is tight? It seems that a gas line must be started at a meter, then prodeed piece by piece towards 'T''s, shutoff valves, and eventually find it's way to the appliances.

A problem to me (in planning my work) is it seems that if you do have a leak and havn't planned on some sort of non threading union, you would have to disassemble the circuit all the way back to the leak. So, what sort of unions are recommended that disconnect without requiring the pipe to be turned?

Thank You in Advance for all input.
ELMDAS
 
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Old 01-08-08, 01:09 PM
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gas pipe

if you plan your gas run as we do we add several unions in the system.we also add several valves,rember what you have now might change several years later.
we started to run our main trunk with black pipe and than run plastic to each device than another valve.
how tight is tight if it dont leak its good.
just about any pipe sealent will work fine.
we test all our systems with air,we add a t fitting as one of our first pices in the run off that we have a air adapter that is placed in the t to pressure the system.when all checks out just bleed off air remove the adapter and add plug.
 
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Old 01-08-08, 06:34 PM
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Gas Piping

In my area, inspectors will not allow unions except for service of equipment. No unions whatever are allowed in the main or branches except just outside the furnace cabinet or other place, downstream of a valve, solely for the removal/replacement of the appliance's gas valve. The sealant you use must be approved for the type of gas going thru the pipe. In some areas, they allow the use of copper tubing. In others copper is an instant failure of inspection.
Please check with local code officials before starting your job. In many areas, gas piping MUST be done by a pro.
 
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Old 01-08-08, 06:55 PM
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Grady and All,

Half the 'pro's' in our area are unemplyed guys with a toolbox, magnetic sign on the door of their truck, and mabey a yellow-page ad. I'm going to be sure this is done well by DIY'ing it.

Quality of the fittings is important to me, and I'm free to use my common sense on the layout, so I'll only place a very few unions to make the system serviceable, keeping in mind that unions are potential places for leaks. That's why I'd like to get good ones. Bet your last buck that they'll be installed well, then tested. I plan to pressureize to 200 PSI or the lowest working pressure of the weakest device on the system, whichever is less. I'll check for leaks immediately after pressureization, and 24 hours later, and will look for a pressure drop.

I bought a can of Hercules Blue Block to seal the pipes. It looks very good by the label, and the fellow at Pierce-Phelps recommended it. It meets MIL-S-451808, and says it's for gasses up to 2,600 PSI, so I think I'm fine on that.

I haven't looked at unions for gas yet, and will want to buy the best possible quality, so if anyone can recommend, please do so. Also, valves. I sure hope this doesn't sound politically incorrect, but I am very unhappy with some of the imported hardware I've seen recently. If a water valkve packing wears out after a few years, it's no big deal, the valve just drips, but with gas........different story. I don't intend to buy anything for gas at the big home improvement stores.


John at ELMDAS.
 

Last edited by ELMDAS; 01-08-08 at 07:30 PM. Reason: Added detail.
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Old 01-08-08, 07:51 PM
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ELMDAS, before you do anything I suggest that you do some reading in the National Fuel Gas Code (NFPA 54)

http://www.nfpa.org/freecodes/free_a...nt.asp?id=5406

You have to agree to the terms and you cannot cut and paste from the on-line version.

Of course your LOCAL jurisdiction may alter any part of the National code so you really need to know what the local code inspector is going to want to see. I'm almost certain that he (she) will NOT want to see any unions except as necessary for appliance installation and removal just as Grady pointed out. Almost certainly the inspector WILL demand that any valves in the system be certified by a national testing agency for the service so that will rule out a whole lot of valves that you may think as superior to the allowable valves.

Do NOT subject the piping to an excessive test pressure as that in itself could be the cause of leaks. The inspector will specify the pressure and test procedure.

What you (an amateur) may "think" is fine, okay or superior is irrelevant. You MUST do as required by your local code and the local inspector.
 
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Old 01-08-08, 08:10 PM
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Politically Incorrect????

You'll get no beef from me or darned few others about the "offshore" fittings. It has nothing to do with politics & everything to do with quality. I refuse to use the imports after too many bad experiences. The supply houses with which I deal all carry Ward fittings, but I'm sure there are other brands just as good. My preference in valves is Appolo (sp?) but again I know there are others just as good, I just can't remember the names.

Blue Block is good stuff just don't dope the end two threads of the pipe (regardless of what sealant you use) & don't get it on the skin or any clothes you care about because it won't come off.

Pressure testing to 200# is major overkill & may do more harm than good. Testing to 50# is way more than ample. We only have to test to 15# but I always go to at least 30.

As long as the gas company will hook up to your piping, I have no heartache at all with you doing the work. If I did, I wouldn't be here. In some areas, they are really touchy about having a licenced plumber or gas fitter do the piping & won't set a meter without documentation of such.
 
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Old 01-09-08, 05:32 PM
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Adding unions is just asking for problems in my opinion. Sounds like you are expecting future leaks. Done properly you won't (shouldn't) have leaks and if you do handle it then. As stated by others ,check your local code.
 
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Old 01-13-08, 08:53 PM
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Some jurisdictions don't even allow a homeowner to do his own gas plumbing but will allow him to do his own electrical. BOTH usually require inspection.

Blue Block is fine but I have found Megaloc to work better for gas. It is much smoother and
non-gritty, and alot easier to get off your hands too!

Working from the meter to the appliance is the correct way to do it. Usually no 'convenience unions' or 'future tees' are permitted. Supporting straps every 3 feet (depending on codes), galvanized pipe outside, black pipe inside, no hidden joints, drip leg and union and isolation valve at or very near the appliance, and a bit more to boot!

So------get the code requirements for your area first, or you may be doing alot of work for nothing and have to call in a certified gas plumber in anyway.

Charlie
 
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Old 01-14-08, 06:24 PM
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Just shows to go ya

There are differences in codes & inspectors from area to area. In my area, ANY galvanized will get you a failure as will Megaloc or any other pipe joint compound containing teflon.

Check with your local officials having jurisdiction over such matters.
 
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