I have a 1" gas line in the crawl space. I want to now add piping for a gas firplace insert, a gas water heater and a gas range. My question is, Can I run 1/2 pipe for each appliance back to the 1" main? Are there any distance requirements that a 1/2" line can run? Do I need to step from 1" to 3/4" then to 1/2"? My longest run would be to the gas fireplace about 50', to the water heater about 15' to the range about 20'.

Thanks a lot for any suggestions.

LP or NG? What is already on this gas line like you furnace? Don't each of these units tell you in the install instruction what size of supply pipe you need? My instant water heater requires a 1" direct line.

It is natural gas. I have a furnace on the line. It also has a 1/2" supply input. Each applicance I want to install has a 1/2" input supply line. My question about the max distance relates to does the pressure get reduced the longer the run.

Thanks

Hi Barry

Gas pipe sizing is based on very specific calculations. The longest run method is based on the fixture that is farthest from the meter, i.e. how far away is the farthest gas fixture from the gas meter. Note here that we are not talking about the farthest gas fixture on the run you want to install (which you said was 50'), but the farthest gas fixture in the home from the meter, OK?

So, what is the farthest gas fixture and as Ballenger (bob) pointed out we'll need to know the other fixtures on the system, too? ALso, what size is the pipe coming out of the meter?

Now, with all that being said, tradition is that if you have a 1/2" tapping into the fixture you will need to run 3/4" over to it and branch off to 1/2" at the fixture/appliance. The only issue here is the number of fixtures you present... all will need to be calculated, OK?

I can probably fit in the calculations for you sometime tomorrow if you provide me with all the information asked for, OK?

Back to you...

Mark

My longest run would be no more than 70'. The line from the meter is 1". I currently have a gas furnace. All the appliances I wish to hook up take a 1/2" supply.

Thanks

Hi Barry

I'm afraid the numbers for this crunch up in such a way that they suggest the need to increase the gas main to 1.25"...UGH!

If you can tell me the BTU INPUT on your furnace and gas insert (I know the other numbers) I can button this down a little tighter...may be the 1" is OK, but by my "on average" calculations that gas insert is going to have some pretty low flames when the furnace kicks on so let me know the numbers and we'll finalize this sometime tomorrow, OK?

Mark

Sorry but I cannot determine the BTU of my furnace I've looked for a tag on the furnace and in the manual that I have but do not see BTU listed anywhere. The furnace is a York affinity 9.c model and comes in either 60 80 or 100,000 BTU. I would suspect it to be an 80,000 BTU model. The house is 2,800 sq ft. The insert we have been looking at is 32,000 BTU. We have a second insert in mind that takes less BTU. The insert is mainly for a little bit of heat in our family room. Mostly decorative.

THANKS FOR YOUR HELP. You are the best.

OK, according to my code you can run 1/2" to the gas fireplace insert, 3/4" to the water heater and 3/4" to the stove....reduce to 3/8" at the fireplace insert, 1/2" at the water heater and 1/2" to the stove, respectively. Otherwise, the whole house BTU count is pretty close... may want to contact your local supplier for final numbers here!

Don't forget to install the ANTI-TIP device at the stove... saves lives! OK?

Mark

You have to do Gas Load Sheet for your entire house. Gas Load Sheet will include developed length for every gas pipe in your house and Gas Load in Btu's for each gas appliance. Also, you will need to call your Gas Company and ask them what's the gas pressure in your area. Based on this information, you size your gas pipe(s).

It is very common that when adding gas fixtures, you will have to upgrade existing gas system to accommodate new gas load requirements.

Question: Do you have gas furnace, gas clothes dryer and gas BBQ in your house ? What's the BTU load for the range ?

Back to you.. . Milo

Hey, Milo!

I did a basic gas load sheet based on the "longest run method" with a 100,000 BTU furnace, a 30,000 BTU dryer, a 40,000 BTU water heater, a 32,000 BTU gas insert fireplace and 55,000 BTU for the range... ;)

I assumed that all appliances were given as I asked, "So, what is the farthest gas fixture and as Ballenger (bob) pointed out we'll need to know the other fixtures on the system, too"!

Anyway, I pointed out that this was my code and I'm figuring I'm pretty close on sizes I recommended, but yeah, as always I'd have preferred to have him consult his local supplier, too!

Thanks...

Mark

Thanks to those who responded to my question. Good answers. I will be getting a permit for this work and it will be passed off by the local inspector. Just wanted to get a leg up on this before I got too far off course.

Thanks again.