Having gas line run: what should I know?

[diggler306]

I'm getting quotes to run a natural gas line roughly 45 ft from my meter to my 24x24 detached garage. My garage is not yet insulated or finished, and I do not have a heating unit yet, but we want to finish our yard so the line has to go down now.

What do I need to know? What questions should I be asking? Will the pipe size be standard for the application? I don't know squat about NG, but that's why there are professionals.

Thanks!

 

[MrMark]

I would never trust "professionals" especially since you don't know the total BTU demand yet - so the professionals would have no idea how to size the line.

Your best bet would be to take command of the situation and google gas line sizing to make sure you get the proper size. I note that the Noritz installation instructions for their tankless water heaters have a very easy to understand and perform gas line sizing example and tables with capacities of various pipes.

If you use the yellow plastic PE pipe be aware that it will need to be larger than comparable black iron pipe sizes for the same nominal size for a given BTU demand. The PE BTU capacity tables as a function of length of run are available online as well.

 

[James-W]

Gosh, I would think just the opposite, I would think a professional heating guy would be able to come out, check everything over, maybe run a few tests, and then tell you just what size heater you need and the size pipe to go along with it. After all, that's what they do every day. I don't think the metal pipe is meant to be run underground either, at least around here it isn't anyway.

 

[diggler306]

You're right - when I said "standard for the application" I'm assuming they would know the correct sizing of heater for a 24x24 installation. Probably a bad assumption if they don't know how I'll be using it.

So let's assume that for my 24x24x9 that I'd need a 30,000 BTU unit to keep it above freezing, with the occasional shot of 60-65 degrees for working out there. Maybe once or twice a week for a couple hours. Probably looking at 60 total feet of line with going in/out of the ground and up the garage wall.

Knowing that, could they not size it correctly?

 

[James-W]

When they come to check it out, I am assuming you will be there to talk with them and you can tell them what you plan to do for insulation and wall/ceiling covering, as well as your intended use for the building. If they know what they are doing they should be able to give you the size of the heater you need as well as the size of the gas pipe. Keep in mind, this is what they do for a living, and it isn't their first day on the job. At least the person who comes to do the estimate will be a seasoned "professional". I rather doubt they would send a "new guy" to do an estimate like this.

 

[MrMark]

If they knew that, they could perhaps size it correctly. You are leaving too much to chance by leaving it to others, but that is just me. Do what you want, but I don't leave something as important as gas line size to others, whether they claim to be a "professional" or not. You know squat about these "professionals" other than that they work at a job.

1/2 inch pipe (iron pipe which is certainly proper to run underground if coated and allowed by code in that area) is good for 73K BTU at 50 feet total developed length. PE plastic pipe would be less. 30K BTU is not that much for a heater. Are you such you would never want a water heater too? Tankless water heater generally is going to need 3/4 to 1 inch line. If it were me, I would run 1 inch PE on a new install at those lengths to save regrets later. I'm sure the cost difference between 1/2 and 1" is very small.

 

[MrMark]

There was just a guy on here posting about his small hanging heater that used 300K BTU's and he thought he had a 1/2" gas line. (He was probably wrong but we'll never know) His setup was done by professionals too.

 

[CNGsaves]

If they knew that, they could perhaps size it correctly. You are leaving too much to chance by leaving it to others, but that is just me. Do what you want, but I don't leave something as important as gas line size to others, whether they claim to be a "professional" or not. You know squat about these "professionals" other than that they work at a job.

1/2 inch pipe (iron pipe which is certainly proper to run underground if coated and allowed by code in that area) is good for 73K BTU at 50 feet total developed length. PE plastic pipe would be less. 30K BTU is not that much for a heater. Are you such you would never want a water heater too? Tankless water heater generally is going to need 3/4 to 1 inch line. If it were me, I would run 1 inch PE on a new install at those lengths to save regrets later. I'm sure the cost difference between 1/2 and 1" is very small.

+1 on highlighted part. Thus, install 1" IPS (iron pipe size) which is YELLOW POLYETHLENE Thick-Wall PLASTIC PIPE that will be cheap at around 50 cents or 55 cents a foot. At each end you'll have Risers which transition the plastic to steel above ground. You will want shutoffs on top of each riser. Also need a tracer wire buried in with the yellow plastic pipe for subsequent locates. Local codes will dictate how deep that yellow plastic pipe is buried.

Get a couple different quotes and let us know. Good luck and congrats on getting your garage insulated and heated!!

 

[MrMark]

BTW, you would need at least 1 1/4" at those lengths to run the 300K reznor heater that the guy on here had. So, this is not some leave it to others type deal.

 

[diggler306]

+1 on highlighted part. Thus, install 1" IPS (iron pipe size) which is YELLOW POLYETHLENE Thick-Wall PLASTIC PIPE that will be cheap at around 50 cents or 55 cents a foot. At each end you'll have Risers which transition the plastic to steel above ground. You will want shutoffs on top of each riser. Also need a tracer wire buried in with the yellow plastic pipe for subsequent locates. Local codes will dictate how deep that yellow plastic pipe is buried.

Get a couple different quotes and let us know. Good luck and congrats on getting your garage insulated and heated!!

Thanks for the info!!

I still do have hope in the human race, and believe that "Professionals" exist for a reason, but you DO need to do your research so that you can ask the right questions, and decipher between the "good professionals" and the bad ones.

I've so far been quoted $500-$600 for one guy, and $900 for another guy. Surprisingly the cheaper of the two sounded the best; having mentioned 1" pipe sizing and describing the locations of the shutoffs.

 

[MrMark]

I think most heaters I've seen on here for that size garage in very cold areas were around 50-75K. The guy with the 300K appears to be an aberration. It could have been that his 300K was only running about 1/4 on!

 

[MrMark]

Professional today just means works at a job. It is a meaningless appellation. The guy who leaves it to the professionals is the guy who finds out later how bad he got screwed. If you put 1/2 hour of thought into this, it will be 29 minutes more than the guy you are paying in a field like this.

 

[diggler306]

I think most heaters I've seen on here for that size garage in very cold areas were around 50-75K. The guy with the 300K appears to be an aberration. It could have been that his 300K was only running about 1/4 on!

e-tek lives in the same city as me and I know he has a 45k Reznor in his 1000sq/ft garage, which he's happy with. Since my space is smaller, I'm guessing I'd fall within the 30-45k range.

 

[CNGsaves]

e-tek lives in the same city as me and I know he has a 45k Reznor in his 1000sq/ft garage, which he's happy with. Since my space is smaller, I'm guessing I'd fall within the 30-45k range.

Depending on what all "heat losses" you have - - - ie garage doors, man doors, windows, etc. - - - along with INSULATION, will determine what size hanging heater you will need.

Given you're in Canada, I'd think for 24'x24' you'd want 45K Btu to 60K Btu.

Forgot couple things about your install: also make sure that all connections are tested for leaks . . . first an overnight pressure test (ie pressurize the line with air pressure and ensure it does not lose any pressure over an extended time period), then finally a soapy liquid test on connections.

Here locally in my city, they have specific code that any hanging heater can not be any lower that rails of the garage door (ie to prevent a tall vehicle driving into the heater and causing a gas leak). Your ceiling height and layout of garage will determine where the hanging heater should be installed.

Good luck. Your quotes in $500 to $600 range sound pretty good if that's end-to-end all the way to the heater.

 

[jvitez]

The first thing you need to determine is heat loss. That tells you how much heat you need to put into the space to hit your design temp. Then gas line tables clearly spell out how big a pipe you need at what distance for that particular gas consumption.

What will you be using the shop for? Will you be opening and closing the garage door a lot? How much insulation will you be installing? Will you be heating continuously or intermittently? Answer these questions and you can get much closer to required heat input. Do this first before you settle on any gas line size.

If you're really really not sure, just install a bigger size pipe than you'll ever need. You'll only be wasting money on the pipe, the labour charge is the same. There's no performance negative to a larger than needed pipe.

 

[diggler306]

Thanks for the input!

 

[diggler306]

Actually, how do I gauge this 'heat loss' number? I have two 9x8 doors, and 8x7 door, a man door and 1 window... so I'm guessing my heat loss number could be higher. But is there a calculation i should be using? Walls are 2x4 so R13 is the best I can do. We upgraded our overhead doors when it was built to ones with a slightly higher R-rating, but I can't remember what that was at the moment.

 

[jvitez]

http://www.ouellet.com/heat-capacity-calc.aspx

Try this link for a basic heat loss calc. Yes, very basic, but this should give you a base number. Put in as much attic insulation as you can. I'd use a min of R40 blown in cellulose but R50 would be better for a prairie climate. Use Roxul insulation for the walls. Ideally you would put 1.5 inches of rigid foam insulation on the outside before finishing the exterior wall. If already finished, you could install it inside the stud wall. Put in as much insulation as you can. It's a one time cost vs monthly cost in NG bills.

FWIW, I had an insulated attached 22x24 garage in our old house. It had R12 fibreglass walls and R40 fibreglass batts in the ceiling, one small single paned window, insulated steel garage door. I heated it with a 4800 watt electric heater as it did OK. It took a couple of hours to warm up to 10-12C from cold at -25C outside temps, and would cool off pretty quick if I opened the garage door, but it worked to thaw cars after washing in the winter or doing the odd project. That works out to 9.1 watts/sq ft.

NG unit heaters are usually ~80% efficient, and 1 watt=3.413 btu. For my garage example I would need 4800 x 3.413= 16,382 btu/hr, divided by .80= 20,470 btu/hr input for a NG heater.

For your space, a 45,000 btu/hr NG heater would give 36,000 btu/hr output, or 10,548 watts equiv, or 18.3 watts/sq ft. You need to do these type of calculations to get where you want to go.

 

[diggler306]

That's great info, thank you!

 

[HoosierBuddy]

Good info so far here.

On 300K hanging heater 'LOL'. The meter to your home is probably rated at 250,000 BTU/hour. 300K BTU/Hour is kind of like asking, "My new compressor takes 250 Amps on 220. What size wire should I run to my breaker?" The answer of course is, "it sort of don't matter'.

To the OP's question...even without a load calculation, I would feel very comfortable running 1 1/4" or somewhat comfortable running 1", because either will haul a lot of gas to 45-feet. 1" PE SDR 11 will flow 294,000 BTU's/Hour at 1/2" pressure drop at that distance. Now, you want to build some "safety factor" in that number for pressure losses due to fittings and such, plus headroom for the future...but that's going to be plenty big for your garage heater, regardless of your load calculation.

The difference in cost between 3/4", 1" and 1 1/4" PE is very small, really and you'll find that the vast majority of your cost is in labor and not material. I just bought 7000 feet of 2" PE this morning, for example, and it was only 80 cents a foot. Ditch costs are measured in dollars/foot, not cents/foot....if you get my drift.

And regarding the professional vs non-professional, that one hit pretty close to home. I've seen a lot of piping situations where too much money was spent because someone just "ball parked" a pipe size based on "gut instinct" and I've seen pipe that was undersized because someone felt it would be "good enough". And these people were "professionals". They just weren't "detail oriented" I guess, to maybe put the best spin on it.

Not a big deal to go 1 size too big if you only need 45 feet of PE. A little larger issue if it's 5 miles of 4" Schedule 40 coated steel.

Good luck. Bury it 18 to 24 inches deep and use a tracer wire. Probably work out well.

Phil

 

[brewchief]

We never run smaller then 1", none of our wholesalers carry anything smaller for the most part anyway.

I would run 1" unless you plan to add a tankless water heater for endless hot water to wash cars or if your adding a pool and might want to run a pool heater off the garage gas supply, if anything like that is planned then a larger line may be needed.

 

[ForceFed70]

Just run 1". There is little cost savings going smaller and no downside to running an oversized line.

 

[diggler306]

No plans for a water heater or anything out there. Not while I'm in this house anyway. 1" sounds like the way to go. I'm getting a BBQ line run first to a spot on my deck, so I'll have some time to talk about the details of the garage line with whoever I choose to do it.

Thanks very much guys.

 

[Tre900]

http://www.endot.com/OpenFile.aspx?path=5f55a_0.pdf&Type=1&pid=42

 

[UpstateNY]

I'll be building a 30' x 40' detached shop about 40' from my house. I gather I cannot run/trench the gas line from the shop to the house and tap into the gas service already installed in the basement of the house ? A seperate gas line must be run from the gas meter to the detached garage ? Assuming this correct, what is the reasoning behind this rule ?

 

[CNGsaves]

http://www.endot.com/OpenFile.aspx?path=5f55a_0.pdf&Type=1&pid=42

Above is SIZING chart so you'll be sure you don't shortchange flow that you will need.

Here is example of actual polyethlene yellow plastic pipe you'll want to bury in ground between meter and garage (consumer version is sized by IPS . . . Iron Pipe Size), so yours likely will be 1" IPS.
http://www.endot.com/products/ygp_pe_2406

Question about connecting to existing gasline in basement versus running over to meter all depends on natural gas demand (ie flow) requirement that the garage will have - - - ie what is Btu of heater, etc? Running the gas line back to near the meter ensures that you get the best flow possible since pressure is highest the closer you get to meter.

As general rule, I would NOT try to connect to existing gas lines in basement unless you have GIANT size pipe from meter as service line into the house like 2" or greater (ie with plenty of capacity, thus EXCESS capacity). If you connect to basement that barely covers the furnace /hot water heater for house . . and now add demand of garage . . . you could starve out both the house and garage and not have proper natural gas flow at both locations.

 

[UpstateNY]

CNG,

Thanks.

Ok, what about coming off the meter with a new line and routing it through the house then out the wall to the detached garage ? Any issues with that ? Trenching from the meter to the new garage would be ugly, routing through the house will save a lot of tear up.