From: jdg@devine.ColumbiaSC.NCR.COM (Jim Griggers)
Newsgroups: misc.consumers.house
Subject: Re: Gas piping question
Date: 5 Oct 92 14:18:21 GMT
Article-I.D.: ncrcae.1992Oct05.141821.6752
Organization: none

In article <1992Oct2.220956.6811@porthos.cc.bellcore.com> patter@dasher.uucp (24224-guthrie) writes:
>
>The appliance supply line must be at least 1/2" pipe. In some cases,
>copper tubing is allowed (I've only seen this used for heaters). If you
>use copper, all fittings must be compression fittings - *no* solder joints.
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The above is contrary to the Standard Gas Code:

 306.4.1.1 Pipe joints may be threaded, flanged or welded and nonferrous
 pipe may also be soldered or brazed with materials having a melting point
 in excess of 1000 degrees F.  Brazing alloys shall not contain phosphorous.

 306.4.1.2 Tubing joints shall either be made with flared gas tubing fittings,
 or soldered or brazed with a material having a melting point in excess of
 1000 degrees F.  Brazing alloys shall not contain phosphorous.  Metallic
 ball sleeve compression type tubing fittings shall not be used for this
 purpose inside or under buildings but may be used or other underground
 connections.

>
>1. All piping and fittings must be "black"; no galvanized stuff allowed.

I have not found this in the national code.  Galvanized may be prohibited
by local code.

>7. Once the job is completed, turn all pilot lights in the house off. Then
>   turn the main gas valve back on.
>8. Test every new joint by applying soapy water. Kid's bubble compound works
>   well for this. Fix any leaks.

Leaks should be tested at pressures above the operating pressure:

 311.1 Procedure and Precautions
 Before any system of consumer's gas piping is finally put in service, it
 shall be carefully tested to assure that it is gas tight.  ...  To test
 for tightness, the piping shall be filled with air or inert gas, but not
 with any other gas or liquid.  In no case shall oxygen ever be used.

 311.2 Method of testing
 Low pressure (not in excess of 0.5 psi) gas piping shall withstand a pressure
 of at least 3.0 psi or 6 in. of mercury  for a period of not less than 10
 minutes without showing any drop in pressure.  Higher pressure piping must
 stand a pressure of at least 10 psi, but never less than twice the maximum
 pressure to which the piping will be subjected in operation, for a period
 of not less than 10 minutes without showing any drop in pressure.

A copy of the Standard Gas Code can be obtained from most techical schools'
bookstores.  I bought mine for a course I took on gas plumbing.  Designing
a gas pipe system for a house is not complicated, but is is more than just
pieceing together pipes.  Gas flow demands for the whole system must be
taken into account before tapping into the pipe system.  In general, most
supplies for homes have plenty of reserve as far as pipe sizing is concerned.

I would recommend getting a copy of the gas code, reading and _understanding_
its contents, and working with your local inspection department.  Remember
the code was written to ensure safety of gas installations.

-Jim Griggers  jdg@devine.columbiasc.ncr.com

>patter@dasher.cc.bellcore.com
>-----------------------------------------------------------------------
>                    |
>George Patterson -  | If you always tell the truth, you never
>                    | have to remember what you said.
>                    |                        Samuel Clemens
>-----------------------------------------------------------------------
Newsgroups: misc.consumers.house