Anybody here fluent in gas line plumbing?

[pick1e]

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[Peartree]

Sizes would be specified in the National Fuel Gas Code, the NFPA (National Fire Protection Association) code or in the local codes derived from them. Unless the runs are ridiculously long, I have usually seen black iron pipe installations of 1/2 inch or at most 3/4 in. used for domestic installations. One inch (1") pipes can accommodate huge outputs like the boilers at church. One of our plumbers can probably give you better specifics and quote from the regulations.

 

[JordanT]

Well, here's a link from Virginia on how to size, straight out of the ICC: https://www2.iccsafe.org/states/Vir...dix A_Sizing and Capacities of Gas Piping.pdf

It's not just a "size" like the electrical code uses, but is based on flow rates (which means distance traveled, pressure drop allowed, and final volumetric flow rate). It looks like the code book has actual examples, including some retrofit. It's not "pick it out of a table" easy, though.

(I should add that this is outside of my area of expertise - I don't do M/E/P work, but I work around this stuff on occasion. There are relatively few things I call in experts for, and this is one of them.)

 

[strake]

Its not that hard based on standard tables. Tips: Find out your gas pressure after the regulator from your local gas company for your neighborhood. The standard codes assume the worst case gas pressure source of 7wc so that you have at least 6.5wc at your appliance. If your gas company says you are near this minimum level then you have to be very careful about fittings and adding equivalent length to determine your pipe size. However if you gas distribution is normal you may have 8-10wc source and then you do not have to worry so much.

You gas range is sized at around 60000 btu likely. Depending on where you tap in to your incoming line you may want 3/4" pipe if your run is longer than 15 feet or so and want to size it so you have enough pressure with all your burners on. Most residential meters will supply about 275000 btu. Figure out how much of this you have already used up from your existing appliance.

 

[strake]

Thanks for the tips strake. I will check on the outlet pressure, I didn't consider that. I just assumed it was nominal. I'm guessing it's good here in the city limits since the inspector didn't bring it up.

I found the table 402.2 referenced by JordanT's info above. Looks like 35,000 Btu/h for the dryer and 65,000 Btu/h for the oven. Here's a link to the table in case anyone else is wondering the same thing:

Chapter 4

The stub for the oven will be coming up through the floor. Wouldn't it be better to have the shutoff valve under the floor (accessible from the basement) or does it need to be above the floor?

Usually the shut-off is in the basement.

Is there an unused run of pipe that you are tapping into or are you adding a new run for your stove? If so where are you tapping into?

You most likely have 1" pipe running from the meter into the basement. Each appliance would likely have its own 1/2" pipe that is tapped into this 1" line.

 

[Oldschool77]

Like strake said your shutoff ''should'' be under your house. If not you'll need to shut it off at the meter, which may legally require a plumber. At that point get one installed under your house. Also I recommend shutoffs at each point you come thru your floor for piece work so you don't have to shutoff your main anytime you replace/work on, an appliance. My line drops from 1''/1-1/4'' down to 1/2'' throughout. Here in OK. natgas is cheaper to use than electricity. Disclaimer-YMMV!

 

[billspad]

The stub for the oven will be coming up through the floor. Wouldn't it be better to have the shutoff valve under the floor (accessible from the basement) or does it need to be above the floor?

You always want a shutoff right at the appliance. You can put one in the basement too but the code (at least in MA) requires one at the appliance.

You need to test your work when you get done. We just pump air into the line and watch a gauge for a few minutes. 3 psi to the appliance gas cock and 1 psi through the appliance (any more risks blowing the regulator). That method will find leaks that are too small to smell. Assuming you don't have a gauge available, you can check it with bubble soap from a toy store. A small leak will make a good sized bubble. Put plenty on every joint and watch. There's no acceptable amount for a leaK so you should never be able to smell gas.

 

[jderimig]

In ohio its hardpipe, shutoff, then flex through the floor to the appliance.

 

[Peartree]

In ohio its hardpipe, shutoff, then flex through the floor to the appliance.

The way I've always seen it was hardpipe through the floor, then shutoff, then flex. You need to be able to reach the shutoff at the appliance because flex is, by code, "supposed" to be replaced more frequently than most anyone really does. I agree, however, that this still makes the shutoff inaccessible in an emergency.

 

[jderimig]

The way I've always seen it was hardpipe through the floor, then shutoff, then flex. You need to be able to reach the shutoff at the appliance because flex is, by code, "supposed" to be replaced more frequently than most anyone really does. I agree, however, that this still makes the shutoff inaccessible in an emergency.

My sample is just the homes in my neighborhood. I can shutoff the gas way faster on my 300# range or my gas dryer by running down to the basement than pulling either appliance away from the wall.

 

[Peartree]

Compared to things like air hoses from an ordinary household/garage compressor, gas lines are barely pressurized. the pressure is typically measured in inches of water column and the maximum is usually around 3 psi. I've opened up LOTS of unions/couplings with gas in them when I worked in an appliance testing laboratory. When you open them up, even under pressure, they just make a sort of poof instead of a hiss. Granted we were in a big room, but there were lots of us running tests. Even at home I've not taken any special precautions. At that pressure, there really isn't much gas to escape into the room as long as the valve is closed.

 

[billspad]

Exactly my point. Oh well. I'm not asking you guys to change the code or anything, just venting on how it seems illogical

Welcome to my world. Around here you can't put a flexible connector through a floor or the side of the cabinet. There's actually some logic behind that. You don't want to shear it off pulling too hard on the stove. Years ago, before flexible connectors, it was hard pipe right to the stove. There was a space inside the top of the stove next to the burners and that's where the gas cock and union went. The union had to be accessible so it was reasonable to put the gas cock there too.

The gas that's in the pipe isn't going to spew into the basement unless you forget to turn it off first. Blowing the gas out with compressed air is a bad idea.

 

[billspad]

Where I'll be opening up the pipe in the basement is a few feet below where it will open in the garage, so I guess it should theoretically float up to the garage instead of into the basement. I'll take your advice and not try to blow it out. What's the risk, static?

You risk accidentally getting an explosive mixture. Natural gas isn't all that dangerous unless you mix it with air. You have to get it just right for that to happen but there's no point in taking the risk. What's in the pipe will dissipate quick enough.

It seems like it would be wise to pressure test the pipe, more scientific than just soap bubbles. I'd have to find a gauge. Home Depot has one for $11 but they don't carry it locally. I'd assume a plumbing supply would have one? $20 for piece of mind would be just fine with me. What do you use to safely add pressure?

You'd think I'd be able to find a picture of one on the Internet but I couldn't. You know the bulb type thing they use to pump up a blood pressure cuff? It's one of those. If you need a picture let me know. I have one in my truck but it's too cold to go out there now.

I was also advised by a plumber a while back to open the valve at the meter slowly after I'm done so that the gas rushing in to fill the pipe doesn't trip a safety mechanism and lock up my meter. Good advice!

I've only seen those on commercial meters around here but it's still good advice.

My last question, I think... I've seen diagrams by manufacturers on where to place the gas hookup and electrical for the range. Each seems to be a little different. Is there a standard location that is acceptable for all brands/models? Or just two inches from the wall wherever it looks right?

I wish. There is no standard. Sometimes 2 inches from the wall is too much. The guys that design these products should be forced to install one.

Don't forget the anti tip bracket. It's there in case your kids decide to use the oven door as a diving board while you're cooking on the stove.