Natural Gas pipe sizing

[sixtyfive]

I am in need of a bit of knowledge with pipe sizing. I have a few questions but Ill start with what I am planning.

Looking to run from the existing house setup to a furnace in my new garage.

My house is currently running the following -
110k btu Furnace - Supplied by 1 1/4" pipe
35.5k btu Water Heater - Supplied by 1/2" pipe
unknown btu Gas Stove - Supplied by 3/4" pipe
Unused run - 3/4" pipe

I read that capacity of the pipe is measured across the entire run. I have a T near my meter after the T for the furnace. Would the 3/4 line be reduced due to this T? If so by how much?

If I replace the unused run of 3/4" with 1" pipe, would that be sufficient to power to supply a 60k - 75k btu furnace that is 200 ft from the meter?

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I am planning to run about 100ft of yellow 1" HDPE pipe between the buildings.

 

[CNGsaves]

With that long run outside for the buried yellow plastic polyethlene pipe, not sure why you are even trying the "shortcut" with some portion of NG supply line through the house??

Why not just connect your buried yellow HDPE just after meter and go all the way to garage?? This is what I recommend as that long run will be tough enough to maintain flow without all those elbows and constrictions in the house. Plus, I sure do NOT think that 1" is going to cut it for that long of a run to garage.

See the attached gas flow chart that I'd recommend you go over with a gas company rep in your local town. You'll only want to bury the right size pipe the FIRST time . . . . go BIG so that you'll have plenty of flow.

Lots of GJ threads on "buried natural gas" so Search / Advanced Search for all the discussion on proper pipe, risers, tracer wire, bury depth, marking all utilities by calling Dig Safe (811), etc.

 

[sixtyfive]

There is an enormous tree about 2 foot away from the lower right hand corner of the house in the attached picture. I do not think I can run around the tree since there is a large exposed root that trails nearly to the edge of my property.

Would there also be cost savings by going around the house? I am not familiar with HDPE pricing.

 

[CNGsaves]

With the tree in way, that does make your options more difficult. See my rudimentary drawing below with the possible buried route for the yellow plastic polyethelene pipe (ie make a big sweeping curve around the corner of the house). Bury depth will be according to local code but generally 18" minimum. If you don't have any low voltage services at the detached garage (ie telephone, internet, cable, security, etc), then you could use the NG trench to serve two purposes - - - ie bury the NG at bottom maybe deeper at 24" and then backfill 8" to 10" and then run another conduit for your low voltage stuff. You'll need to see if that is allowed for your local code.

Around here yellow plastic pipe for buried NG is around $0.55/ft so cost is fairly cheap, but that was for me buying 1" size (my garage is only 20 ft . . PLUS $ for risers on each end still needed along with shutoffs at more cost). You'll likely need 1 1/2" or so depending on what local pro at gas go tells you for that long of a run and 60K or 75K Btu heater in detached garage.

Doing the "shortcut" through house might work but you may have to upsize NG supply line back to meter to 1 1/2" or 2" and do away with those 3/4" sections. You'll want NG flow to be pretty straight all the way to your exit of house above ground then use riser and the buried yellow plastic pipe to get over to garage. If ANY changes are made, make absolutely sure pressure tests and leak tests are performed. SAFETY is # 1.

I'm no expert but sure looks like you'd need 1 1/4" or 1 1/2" end-to-end pipe size, or larger. The local pro at gas company should be able to fill in some of blanks and cover code requirements. Local plumber should be your friend as well. Good luck.

 

[sixtyfive]

I will do some hand diging tonight around the problem root to see where it dives deep enough to clear.

I spoke with the gas company this morning. They no longer get involved in gas runs after the meter and suggested I contact a local plumber.

I did find out that my supply is rather low for the area. 7" of water column. He suggested sizing the line larger than what I think I will need in order to compensate.

 

[sixtyfive]

I did a bit of digging and have an 8" diamater root where I was thinking I would be good. I am thinking running through the house may be my best bet. I had a guy that works for the local gas company quote me $400 for 200 ft of 1" HDPE with risers. He said he could put together the 100 ft run for about $70 less. A bit high, but I do not know how much work is involved in attaching the risers.

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[ljhhontx]

I work for the gas company in Texas and I may not understand your drawing fully but it looks like coming off the end of the 1 1/4" going to existing furnace is your best bet, that 1 1/4 is good for double what you have on it now. You are right in that the total volume is helping your capacity, even the unused 3/4 run is volume, if for some reason I am misunderstanding and wrong you could also tie in the 3/4 to the run going to the garage, it looks close on the drawing. Also, the yellow plastic has reduced friction and you probably don't need any ells in it, it bends easily. T.he chart I attached is for 7" wc, remember that you also consider the appliance because of variations in pressure drop, just because it's a 7" system doesn't mean they all actually need 7" wc

 

[sixtyfive]

I work for the gas company in Texas and I may not understand your drawing fully but it looks like coming off the end of the 1 1/4" going to existing furnace is your best bet, that 1 1/4 is good for double what you have on it now. You are right in that the total volume is helping your capacity, even the unused 3/4 run is volume, if for some reason I am misunderstanding and wrong you could also tie in the 3/4 to the run going to the garage, it looks close on the drawing. Also, the yellow plastic has reduced friction and you probably don't need any ells in it, it bends easily. T.he chart I attached is for 7" wc, remember that you also consider the appliance because of variations in pressure drop, just because it's a 7" system doesn't mean they all actually need 7" wc

If pulling off the 1-1/4" would not starve my existing home furnace then I would not be opposed to pulling off of it.

I was worried that the unused 3/4" line was already diminished in strength by being after the T for the 1-1/4" line, and on the same T as two other appliances. When calculating a line do you need to subtract or divide gas flow to account for other devices before or at the T?

The line between the house and garage on the first drawing does not currently exist. I could either place the line there, or wrap all the way around to the back corner of the garage where the furnace will be.

Is it fairly easy to attach the risers to the pipe? I found a source online.

1" x 150' HDPE pipe $121.59 http://naturalgasplumbing.com/Yellow-Pipe-1-IPS-X-150-FT-PE-2708-DR-11.html

1" flex riser $86.45 x 2 http://naturalgasplumbing.com/Flex-Riser-1-IPS-.119-Wall-1-MPT-36-L.html

 

[10kredline]

If this is any gauge for you, adding on to what the Texas gas man said: I ran 1 1/4 yellow gas line from my meter to my 14 kw standby generator, and that run is about 110 ft from my meter. The generator set can pull about 200k btu/hr when loaded down, and I've purposely loaded it down and my line pressure remained between 5 and 6 inches w.c. at the generator. My line for the gen is tee'd at the meter, so my run is separate from that of the boiler and water heater. I measured the gas line pressure at the generator while it was running, with the boiler and gas kitchen stove all running. If it's any help, I live in a low pressure area according to pse&g, and I do not have a pressure regulator at my meter. Hope it helps. And my gas line to the generator is totally under ground.

 

[plumbstupid]

To feed a 75k btu furnace at 200 feet away you will have to run atleast a 1.25 inch line and there probaly will not be enough volume left to run anything else in the shop. You should be fine to tie into the riser off the meter as long as the line going to the shop is sized correctly.

 

[sixtyfive]

Well.. I found a concrete patio under my paver patio where I was planning on trenching to the house!

Looks like its on to plan B. I will either try wrapping around the big tree to the meter, or go between the trees and drop in below the picture window.

Even the most conservative chart I looked at showed 1" should be able to run 84k btu at 200 ft, but I may still go with 1-1/4" just in case.

 

[ljhhontx]

I understand your situation now may dictate the 1.25" line from meter and agree you shouldn't limit possible upgrades by going 1", the money is in the labor not the pipe, I've been trying to convince stubborn homeowners of that for 25 years. I do have some questions though since I have never dealt with a utilization pressure system myself. All of the systems I have been involved in run at least 10 to 30 psi with regulators at the meter.
If the gas company tells you that you are in a low pressure area does that mean your meter pressure can fall below 7" wc at outlet? If so they can't honestly bill you by the meter reading since it is dependent upon a set pressure to accurately measure the gas sold. Also are you limited to a 3/4" outlet at the meter because you are almost at the limit of the standard 250 cfm residential meter if you figure 100% load.
If you have the time please post a good photo of the meter and adjacent piping it may clear up some of my misunderstandings.

 

[CNGsaves]

Those prices for yellow polyethelene are OUTRAGEOUS . . . nearly $1 a ft !!

Also the riser prices are sky high as well.

OP if you ever get up to Kansas City area, I recommend you consider using Groebner & Assoc, 4949 Hadley St, Overland Park, KS 68203
(913)384-1510
for your buried NG components. These were my prices last year:
- - - - 1" yellow "polypipe" (ie thickwall polyethelene) at 55 cents / ft
- - - - 1" riser (30"v x 30"H w/ 8" pigtail) at $39.43 each end
- - - - Stablock connector (ties pipe & riser together) at $27.14 each end
- - - - chamfer tool for stablock at $29.86 (one time purchase !!)

Only thing extra would be shutoffs on each end which I already had (best ones are high flow and can be padlocked - - ie for exterior use). Remember my garage is only 20 ft away so I oversized it for my 50K Btu heater, but 1" is surely inadequate for OP's long run.

I still recommend OP that you go BIG so this will be done once, and never have to worry about it again. Also, you'll want yellow tracer wire buried in the trench about 12" from the surface. Thus, my .02 advice is go 1 1/2" which is tied into NG supply just past the meter (ie maximum flow) and all one continuous piece to aid flow. Plumber and gas company locally are your friend.

 

[HoosierBuddy]

1. Don't forget to call 811 and get locates before you dig.

2. 1 1/4" would be my choice. Taking 70k BTU to your garage will not starve your home. The 1 1/4" line you have now is more than sufficient to carry all the gas the meter will deliver (likely about 275k BTU).

3. The guy from the gas company is being a bit greedy IMHO...but let's face it. A lot of HVAC stuff gets marked up 100% and he is buying it retail (I'll assume he's not just taking it out of the gas yard?) himself and marking it up to you. Putting the risers on each end takes about 10 - 15 minutes using standard **** fusion (counting the time for the heater to warm up), 5 minutes using EF couplings or 2 minutes using stab couplings.

4. A good trencher would likely cut that root for you. Not sure if that's dangerous to the tree. Probably not "good" for it though.

Good Luck!

Phil

 

[sixtyfive]

Those prices for yellow polyethelene are OUTRAGEOUS . . . nearly $1 a ft !!

Also the riser prices are sky high as well.

OP if you ever get up to Kansas City area, I recommend you consider using Groebner & Assoc, 4949 Hadley St, Overland Park, KS 68203
(913)384-1510
for your buried NG components. These were my prices last year:
- - - - 1" yellow "polypipe" (ie thickwall polyethelene) at 55 cents / ft
- - - - 1" riser (30"v x 30"H w/ 8" pigtail) at $39.43 each end
- - - - Stablock connector (ties pipe & riser together) at $27.14 each end
- - - - chamfer tool for stablock at $29.86 (one time purchase !!)

Only thing extra would be shutoffs on each end which I already had (best ones are high flow and can be padlocked - - ie for exterior use). Remember my garage is only 20 ft away so I oversized it for my 50K Btu heater, but 1" is surely inadequate for OP's long run.

I still recommend OP that you go BIG so this will be done once, and never have to worry about it again. Also, you'll want yellow tracer wire buried in the trench about 12" from the surface. Thus, my .02 advice is go 1 1/2" which is tied into NG supply just past the meter (ie maximum flow) and all one continuous piece to aid flow. Plumber and gas company locally are your friend.

I found a local place that has 1" for cheaper, but the price jumps up when you go larger.

1" pipe .65 per ft
1-1/4" .93 per ft
1-1/2" .99 per ft

1" flex riser $45
1-1/4" flex riser $79
1-1/2" flex riser $104

I think the steep price change is because this place only stocks 3/4" and 1". Ill check and see if any towns nearby have it for cheaper.

 

[sixtyfive]

I understand your situation now may dictate the 1.25" line from meter and agree you shouldn't limit possible upgrades by going 1", the money is in the labor not the pipe, I've been trying to convince stubborn homeowners of that for 25 years. I do have some questions though since I have never dealt with a utilization pressure system myself. All of the systems I have been involved in run at least 10 to 30 psi with regulators at the meter.
If the gas company tells you that you are in a low pressure area does that mean your meter pressure can fall below 7" wc at outlet? If so they can't honestly bill you by the meter reading since it is dependent upon a set pressure to accurately measure the gas sold. Also are you limited to a 3/4" outlet at the meter because you are almost at the limit of the standard 250 cfm residential meter if you figure 100% load.
If you have the time please post a good photo of the meter and adjacent piping it may clear up some of my misunderstandings.

I will get you a pic.

Gas company said that I do have 7" wc, not sure if that is at the outlet or not.

 

[sixtyfive]

Well I finally got around to ordering the 1 1/4" line and risers on Friday. I was also able to clean up my trench and get it dug up to both buildings just before the freezing temperatures got here.

Here are the pics of my meter. I should be able to T into the galvanized line before the rest of the runs and then exit the house near where the longer galvanized pressure release line exits.

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I lost a week and a half due to an auction which led to losing second gear in my truck. I was able to get a junkyard transmission swapped in that hopefully has less abuse on it. This was my first time removing and replacing an auto trans so I had some learning along the way. I also got my rear main seal replaced while I had it apart so my garage floor will be thankful!

 

[ljhhontx]

Looks good to me, you have a 1" outlet on the meter, keep in mind that if you add any more appliances the meter shown will only pass 250 cubic feet per hour which translates to 250,000 btu and the regulator will pass around 350 cfh without a pressure drop, you can ask the utility for a larger meter and regulator if that occurs. Glad you got everything underway.