Gas line size?

[BB16]

Hey guys, so I have a modine hot dog 100k btu heater that I’ve ran the last 3 years off propane. The tank sat 8’ behind the barn. I recently got natural gas at the house and I need to trench a new line going 140’ from the meter to where it connects at the barn. It then has about 40’ of black (rubber maybe) flex line that runs inside the barn to the heater.

My question is, is 1” poly line big enough? I have one company telling me 1” is fine, and one saying they should do 1-1/4”. I already have all of the supplies for 1” laying around, so if it will work correctly, I’d like to use them. Otherwise it’ll cost me a couple hundred more bucks for a bigger line and risers. I’m not against that if that’s what’s right. Just curious if you guys with experience know if I can use the 1” effectively.

Thanks in advance!

 

[housewolf]

100K BTU requires 91 CFH tapping into the main after ther regulator could effect an existing appliance on that system. If the unit heater is all you have, it appears you could get by with 3/4”. To be certain it will work properly, you really need to use something like this to design the entire system.

 

[PoorUB]

What is the gas pressure out of the meter. It makes a huge difference.

At .5 PSI gas pressure it looks like 1" will do it, if you have 2 PSI you can do it in 1/2 ID.

 

[gmcgeo]

Need to know what the working pressure from the meter to give you the answer to your question

 

[bradthefixer]

1/4 lb is typical psi after the meter so volume (pipe inside ID) is more important then psi. housewolf is correct, don't starve existing appliances so bigger is better. What type of tubing are you using inside and outside, be specific. I have been installing gas mains/lines for 23 years for public utility.

 

[PoorUB]

1/4 lb is typical psi after the meter so volume (pipe inside ID) is more important then psi. housewolf is correct, don't starve existing appliances so bigger is better. What type of tubing are you using inside and outside, be specific. I have been installing gas mains/lines for 23 years for public utility.

Typical? For where? Here 2 PSI natural gas is typical for a residential meter.

Also the gas pressure is indeed important. Read my post.

I ran gas to a new funace in my dad's house. At low pressure I would of had to run 1-1/4". With 2 PSI I ran 1/2". I had to "school" the guys at the local utility as they had never heard of it! They started spouting of code and I pulled out my code book and showed them it was allowed.

 

[BB16]

Sorry for the delay. I’m waiting to talk with the tech to see if we can up the pressure at the meter. He said it’s typically .25psi

I’d love if we could up it to 2psi if that’ll work with the current 1/2” line that’s buried and hooked up

 

[BB16]

1/4 lb is typical psi after the meter so volume (pipe inside ID) is more important then psi. housewolf is correct, don't starve existing appliances so bigger is better. What type of tubing are you using inside and outside, be specific. I have been installing gas mains/lines for 23 years for public utility.

Makes sense. I checked with my provider, it’s 1/4lb after the meter. Right now I have what looks like 2” coming in the house before it gets to 1” copper to run to the appliances. I’ll see if I can attach pictures.

The second line from the meter going underground runs out to the barn. It’s the only propane line. It’s 1/2” poly but obviously doesn’t push enough gas to get there

 

[housewolf]

In my experience, 40+ years as a master plumber, a 2 psi residential gas service is uncommon, but it’s gaining popularity as gas supplies become less stable. Admittedly most of my experience is regional and commercial at that. 2-5 psi isn’t uncommon in commercial work since it can allow us to run 2” screw pipe in lieu of 6” weld pipe. That’s a huge cost savings.

Working pressures of natural gas are generally measured in WC (water column) and 5” to 7” is pretty common for the working range of gas appliances. If you have a 2 psi (56” WC) service you’ll have to add at least two regulators in the system. One before it enters the existing house, and another at the heater.

Thats really not big of a deal to use a couple of regulators (some need to be vented) but you‘ll have to weigh the pluses & minus of what’s more cost effective for your situation

 

[The Cobbler]

in my area, 3.5" WC is common after the meter reg on residential services

 

[Death Row Dave]

7 IWC is “ Normal “ house Line Pressure . We had up to 60 psi up the the first stage regulator . 1 iron pipe size plastic was used for the last 20 years of my employment in LDC . I also worked 35 years on top of a 9 million gallon LPG cavern . 11 IWC was used on LPG Service . LPG is 2.5 x higher BTU per cubic ft over Natural Gas . We did not service any customers with LPG , it was used for peakshaving the Natural gas system on cold high demand days .

 

[PoorUB]

Sorry for the delay. I’m waiting to talk with the tech to see if we can up the pressure at the meter. He said it’s typically .25psi

I’d love if we could up it to 2psi if that’ll work with the current 1/2” line that’s buried and hooked up

If your provider will bump the gas pressure to 2 PSI you will need to retest the existing gas lines. You will need to disconnect an cap the lies at each appliance and at the meter. Here we pressurized the line to 25 PSI and it should not drop. A tiny, unnoticeable leak at low pressure becomes noticeable at 2 PSI!

Also you will have to add regulators at all of the appliances to drop the 2 PSI to low pressure. Often we would run part of the home at 2 PSI , then regulate one area down to low pressure, for example a mechanical room with multiple gas appliances.

 

[Jackfre]

All the “correct” engineering aside I always oversize gas lines and other services. Why, well you just can’t anticipate what your future needs are going to be.

 

[housewolf]

All the “correct” engineering aside I always oversize gas lines and other services. Why, well you just can’t anticipate what your future needs are going to be.

That’s what I always did years ago when I started in residential. On commercial work the mech engineers usually size the pipe for us based on demand and future expansion.

I’m retired but still slightly involved with a small service company. It seems once a week we run into a customer adding an emergency generator. When you make a huge demand tap like that, usually outdoors at the beginning of the line, sometimes branches inside the house are too small requiring you to up the pressure & add a regulator.

 

[bradthefixer]

Typical? For where? Here 2 PSI natural gas is typical for a residential meter.

Also the gas pressure is indeed important. Read my post.

I ran gas to a new funace in my dad's house. At low pressure I would of had to run 1-1/4". With 2 PSI I ran 1/2". I had to "school" the guys at the local utility as they had never heard of it! They started spouting of code and I pulled out my code book and showed them it was allowed.

The service line feeds the regulator, then the gas enters the meter, AFTER the meter 1/4lb is typical, after an appliance regulator 1/8lb is typical. Yes 2lb is very common also 10lbs and 60lbs. Yes, pressure is important never did I say it wasn't did I? When you tap into the fuel line AFTER the meter you will have 1/4lb therefore you need volume as you will only have 1/4lb of psi. Does your code book tell you to comprehend what you read before you imply others are not as educated as you are?

 

[gmcgeo]

A lot of mixed info, with a little truth in each post. PoorUB is correct.

I feel i would argue a lot on this matter so ill leave it at that.

Anyway you look at it, you will need step it down with regulator at the building to get your 1/4 into the building. Or have a the gas company put a meter at the building.

 

[PoorUB]

When you tap into the fuel line AFTER the meter you will have 1/4lb therefore you need volume as you will only have 1/4lb of psi. Does your code book tell you to comprehend what you read before you imply others are not as educated as you are?

Wrong old wise one!

I love the part in red, perhaps you need to read YOUR code book!

We run 2 PSI inside homes all the time, very common here, meets International Mechanical Code. It is great because you can pipe a house in 3/4" and 1/2" in most cases unless you have some huge house.

 

[HamAndEggs]

2PSIG meters are getting more and more popular here in Houston, I see them all over. Probably because every other house now has a generator

 

[ripperd]

Here in MN our last two houses have been 2psi after the meter. Meter outside. Then in the mechanical room there has been a regulator stepping it down to 0.25psi, then a manifold with home runs for all the appliances.