Pex line and Natural Gas

[Bill Bob]

Why is it not recommended to use Pex for an extension to a outdoor propane grill that I plan to convert. I understand that Pex is rated for something like 125 PSI and natural gas is perhaps one or three PSI. Aside from some codes why?
Bill

[Robert Adams]

I don't get it either. They use a plastic pipe for in ground big gas lines and even the service line to the house or business but we still don't have a pex type product for house use. Makes me think it's an issue like with certain regions and their unions pushing the use of conduit in houses to increase profits for companies...

Gas pressure in most houses is a half a pound of pressure. The piping is way overkill but then they allow that flimsy flex stuff at appliances... There is csst but personally I would trust pex over it any day. Csst likes to get pinholes when there is a lightning strike but it wouldn't phase pex.

Also the plastic the gas company uses is very durable. Ever seen how they ship off a line? They just put a clamp with two pipes and a hydraulic jack and pinch the line shut.

[blackhat]

Fire

[Bill Bob]

Fire?? Looking on the net I see a lot of problems with black iron pipe and cracks along with pipe dope that deteriorates after time. I do not see any regulations or codes on the manufacture of iron gas pipe that mostly comes from Asia. Looks like Pex may be a better option than Csst. Just not sure, seems to be arguments on both sides. The jury is still out.
Bill

[blackhat]

The codes and standards for steel pipe and malleable iron fittings exist. The codes are actually quite explicit on the standards that every component of a gas piping system must meet. If people are using substandard materials, that is not a code issue. It is an enforcement issue. Do you ask your plumber if he uses code compliant material or do you ask for the cheapest price? People laugh at third world building standards and then want their work done for the same money.

[John Mihich]

How does it last in sunlight? I know PVC has issues.

[Robert Adams]

John Mihich said:

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How does it last in sunlight? I know PVC has issues.

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Doesn't matter really. Gas pipe is almost all shielded from sunlight either in walls under the house in the attic etc. Should be treated just like water pipes and use ridgid pipe in places it needs to be.

As to fire? They used black pipe for years from the main to the meter. Look what happens to that over time it rusts through and the connections they used have caused many house explosions. It's a big deal here but there isn't much you can do about it. Ridgid pipe and moving soil is a bad combination .
I don't see the data for why a plastic isn't used. And probably because they can't uphold the claim. It works just fine in the ground why not the house.

[blackhat]

Sunlight isn't the issue. UV light is. Many standard light fixtures will produce enough UV to degrade plastics. Water leaks aren't generally as catastrophic as gas leaks, risk acceptance. There are piping practices to deal with shifting soil, they increase cost of installation, lets have our wallets on third world standards and blow a few houses up instead. Code says the piping must be protected from abnormal hazards and corrosive environments, Was it at time of installation? Who changed what without regard for consequences? Why not change all the gas lines in your house to garden hose? Its quick, easy, cheap and any monkey can do it. Who will you sue when it fails? Provided you are still around to sue someone.

[Robert Adams]

blackhat said:

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Sunlight isn't the issue. UV light is. Many standard light fixtures will produce enough UV to degrade plastics. Water leaks aren't generally as catastrophic as gas leaks, risk acceptance. There are piping practices to deal with shifting soil, they increase cost of installation, lets have our wallets on third world standards and blow a few houses up instead. Code says the piping must be protected from abnormal hazards and corrosive environments, Was it at time of installation? Who changed what without regard for consequences? Why not change all the gas lines in your house to garden hose? Its quick, easy, cheap and any monkey can do it. Who will you sue when it fails? Provided you are still around to sue someone.

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The steel pipe and connections are what cause more explosions here. Now plastic is code for in ground. Only a few citys allow epoxy coated pipe in the ground now.

Still uv is not an issue in a house as the pipe is not subjected to it. No one mentioned using garden hose etc. What scientific reason is there for not having a plastic pipe for gas in a house. They allow or used to allow that CSST pipe which is way weaker than plain old pex. It corrodes and pinholes from lightning. It's so bad that many city's have made it against code to use and insurance companies are paying to have it replaced in houses.

[daddo]

I find the comments entertaining and amusing. Trying to justify using pex where it is not allowed- as if the situation hasn't been tested or investigated by the experts.
No, there isn't much available pressure in the gas line, but open up a 3/4" pipe and stick a match to it and see just how big a flame you get, you'll be amazed- I've done it. On second thought- don't do that.

Pex may melt down somewhere around 320*- 375* I'm told, but I've never seen a metal flexible gas connector or steel pipe melted at an appliance after a fire.

Your cooking a nice batch of fajitas on your grill and a small hot burning ember falls out of the grill onto the pex unaware while your chugging down that brewski thinking life is good.