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Sizing gas pipe with elevated pressure.

Daddy-0-

Daddy-0-

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Joined
Oct 24, 2009
Messages
855
Location
Powhatan, Va.
The contractors figured out that if they undersized their CSST gas pipe they could adjust to elevated pressure and make it work without having to tear out and start over. The problem is that you need to install a second stage regulator which can cause multiple variables. The regulators could go at the appliances or you could have a whole house regulator before the manifold. The different locations can have huge impacts on sizing the gas pipe. Do you require that at the rough in gas inspection the contractor provide the location of regulators? If not, how do you properly check the size of the gas pipe?

Remember that we are talking about elevated (2psi) pressure. Thanks.
 
At Plan stage I require a basic size and design of the gas piping. With an assumed pressure base on Gas company delivery. Many/ Not gas heaters come with step down regulators on them. There is a lot more to the issue. What the contractor are doing is fine. I believe what you are asking is how will you understand what is happening in the field? Perhaps, if they change from the original design and pressure they need to contact you to discuss the locations.
 
The problem is that we don't require a "plan" for residential. The permit description tells us the # of appliances, the btu load, what type of gas, and what the pressure is. Past that, we have to just look at it in the field. The problem is that someone else had the rough-in and you have the final and you discover the regulator in a strange place (i.e whole house regulator in the crawl when you are looking for a regulator at each appliance). If you take elevated pressure all the way to the appliance you can have smaller pipe. I am trying to get the office to require the permit description to list the location of all regulators with elevated pressure but I am getting resistance. The gas fitters in the office say that they can tell at rough in where it is going because of a union here or a "t" there. Am I making sense? Does anyone else have these problems?
 
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