Re: gas pipe sizes for several applicances
Posted by Sylvan Tieger on April 04, 2004 at 18:29:28:
In response to Re: gas pipe sizes for several applicances
: gas pipe sizes for several applicances

: As I am installing a gas hot water heater, dryer, furnace and stove. The hot water heater and dryer are close to meter as they are in basement while the stove and furnace are on second floor and third floor. 65 feet is the longest run to the furnace.
: Can I use 3/4 pipe and tee to 1/2 pipe for each applicance?

: Thanks Mike

Hi Mike, when working with "gas" one would have to know the type of gas LP or natural.

Natural "gas" has heating values that vary from 900 -1,200 BTUs

Developed length has to be known plus the actual BTU INPUT of each appliance.

When I size gas lines I also check with the local gas supplier for the specific gravity of the gas IM using and the actual incoming pressure.

Does your locality require drip legs?

Personally I never run less then a 3/4" line to an appliance then use reducing couplings as required.

The NFPA is a great place to start and so is your local plumbing codes and the ASME section IV as you want to allow for "free air" for complete combustion as folks do not like CO in their homes.

Your gas meter may have to be increased as well as your incoming service if applicable

The actual BTU input is easy enough to find so is the actual running of the piping The real problem is sizing vents properly and air for proper combustion.

Are you going to run a flue through flammable materials and need a double wall pipe?

Is your location very windy where you may need a Swiss cap for proper up draft?

There is a whole lot to consider with gas piping and you may find it cheaper in the long run to hire someone licensed and insured.

Good luck



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