lobottomee
New member
- Joined
- May 21, 2005
- Messages
- 3
I stumbled across your post by accident, but because of its' nature I feel compelled to reply, even though it's quite late. I am an Operations Manager for one of the largest gas and electric utility's in the country. I also spent a good part of my career drilling oil and gas wells in the Appalachian basin, many in the northwestern part of Pennsylvania. Altogether I have over 30 years in underground utility experience, primarily gas, so please listen to me. DO NOT, DO NOT, DO NOT build over an underground gas line unless it's been properly engineered.
Based on your post I'm assuming you're going with slab on grade construction. If you pour over top of an underground gas line you effectively "cap" the ground surface, creating an extremely dangerous condition in the event your gas line develops a leak. Gas, being lighter than air, will seek any avenue to rise. Normally it'll rise up through the soil and disperse harmlessly into the air. But if the ground is capped, like a concrete floor, the gas will rise through any crack or opening, potentially collecting in your building. If you have a crack in your floor, that's where the gas will go. Or through a drain, or an electric conduit into your breaker box. In the winter it gets even worse because the frost outside the building acts as a cap too, channeling even an outside leak into your building. In the right concentrations the gas will explode. In fact, I can tell you how it'll explode. The roof will go up in the air, the tops of your walls will be blown to the outside, and the roof will collapse back down until it hits the ground. Not to mention the fire ball. Anyone inside, or nearby outside, runs a real risk of being killed or seriously injured.
The best method of building in an area of underground gas lines is to relocate the line a safe distance from the building. But if you must build over the top, the pipe must be completely sleeved under the entire length of the building. At least one end of the sleeve needs to be vented to atmosphere. The sleeve and the vent will channel any leaking gas safely to the outside.
While the degree of hazard for building over an electric line is less, it's still very poor practice unless you put the wire in conduit. I can't speak to water, but from an engineering perspective it seems pretty silly to do it, again unless you the pipe in a conduit.
If you've already built your building over the gas line, you're risking your life if you leave it that way.
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Based on your post I'm assuming you're going with slab on grade construction. If you pour over top of an underground gas line you effectively "cap" the ground surface, creating an extremely dangerous condition in the event your gas line develops a leak. Gas, being lighter than air, will seek any avenue to rise. Normally it'll rise up through the soil and disperse harmlessly into the air. But if the ground is capped, like a concrete floor, the gas will rise through any crack or opening, potentially collecting in your building. If you have a crack in your floor, that's where the gas will go. Or through a drain, or an electric conduit into your breaker box. In the winter it gets even worse because the frost outside the building acts as a cap too, channeling even an outside leak into your building. In the right concentrations the gas will explode. In fact, I can tell you how it'll explode. The roof will go up in the air, the tops of your walls will be blown to the outside, and the roof will collapse back down until it hits the ground. Not to mention the fire ball. Anyone inside, or nearby outside, runs a real risk of being killed or seriously injured.
The best method of building in an area of underground gas lines is to relocate the line a safe distance from the building. But if you must build over the top, the pipe must be completely sleeved under the entire length of the building. At least one end of the sleeve needs to be vented to atmosphere. The sleeve and the vent will channel any leaking gas safely to the outside.
While the degree of hazard for building over an electric line is less, it's still very poor practice unless you put the wire in conduit. I can't speak to water, but from an engineering perspective it seems pretty silly to do it, again unless you the pipe in a conduit.
If you've already built your building over the gas line, you're risking your life if you leave it that way.
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