Gas is dangerous

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We (most of us, anyway) tend to take a pretty cavalier attitude toward the energy sources we use, such as gasoline, electricity, and flammable gases. This was recently brought home to me, again, on a couple of jobs.

I got a call from a contractor who said one of his clients had hooked up some barbecues, and they weren't working. With a few questions, I found out that they had called the local gas utility, and the technician who came out hooked up a manometer to the gas line. I guess it shot the water from the manometer high into the air when he turned it on. So, stating the obvious, he said that a regulator was needed.

Fortunately, I know a little about this property, and I know that they have a large system of 5 psig natural gas lines going all over the place. Most appliances, including these barbecues, expect around 8" of water column, or 1/4 psig. Some have individual regulators bringing the pressure down to 5 inches or so. Whoever tried to light these barbecues is fortunate that he or she was unable to do so, as they were being supplied by approx. 20x the amount of pressure that they require. I was able to install a regulator in the cabinet, with the vent piped to the open atmosphere outside the cabinet. Since I had found multiple leaks on the piping inside the cabinets before I started, I also dis-assembled and re-assembled all of the gas manifolding in the cabinets. Realizing that these appliances use about 1/2 million btuh, which is easily supplied at 8 inches of water column, 5 psig is an enormous amount of gas supply.

We were working at a large retail complex recently, and noticed a smell of gas near the door we were entering. At first, I assumed that it was the regulators venting at some large meters nearby. However, it seemed kind of strong, and always present, so I had my helper get his soapy water spray bottle, and we took a look. We found lots of bubbles. There were several screwed joints leaking, and surprisingly, some flange gaskets leaking as well. This was outside our scope of work, so we notified the responsible parties.

Moral? 1) Don't hook up gas appliances unless you know what you're doing. 2) If you keep smelling gas near a meter, call the gas supplier.

It's kind of surprising that someone working in an area that has 5 psig gas lines would just directly hook up an appliance. That is a disaster waiting to happen.
 
Good to know. Hoping to build a home one day that has a NG backyard grille. Beats lugging around tanks of propane.
 
M's Pub in the Old Market in Omaha was destroyed 01/09/16 when a gas explosion occurred in the basement. A sub-contractor installing fiber- optic cable struck a natural gas line and the gas followed the line into the Pub basement. Building is a completed loss as only the brick walls are left standing. Took Metropolitan Utilities District over an hour to find the valve to shut the gas off. Litigation will begin soon. Verizon, contractor, sub-contractor and MUD will probably all be sued. And insurance companies will also be part of the litigation. You are right about smelling gas. Those inside M's, the apartments above and residence of adjoining buildings and business will all be seeking compensation for loss. Law suits will probably go on for years. Will be rooting for Denver but don't think they have the horsepower to pull it off.
 
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Originally Posted By: dishdude
Obligatory photo...

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OMG!.

Those poor people with the tiny back yards.
 
I believe the natural gas main pressure for my area is ~40psig and the regulator at our meter units knock that down to 2-4psig.

Never heard of over-pressurization happening with gas at a residence, but I have with water.
 
Gas can be real dangerous. I just recently put a new gas water heater in at my grandmother's house. Once I was done installing it, I sprayed some soapy water on the shut off valve (very very old) and it was leaking so i had to put a new one in. All I did was turn it off while replacing the water heater.

Everyone, don't forget to spray some soapy water on a valve even if all you did was turn it!
 
7" W.C. out of the regulator is typical for residential service. We have 2 lb. gas here since our standby generator requires 14" W.C. but there is a regulator installed on each appliance.

Originally Posted By: JTK
I believe the natural gas main pressure for my area is ~40psig and the regulator at our meter units knock that down to 2-4psig.
 
We had an explosion in the area over the summer. As it turns out the electrician upgrading an electric service grounded it to a gas pipe instead of a water pipe. Not good. At least that's what my nephew a volunteer fireman told me. I've heard one or two other stories like that over the years.
 
Originally Posted By: Stelth

Moral? 1) Don't hook up gas appliances unless you know what you're doing. 2) If you keep smelling gas near a meter, call the gas supplier.

It's kind of surprising that someone working in an area that has 5 psig gas lines would just directly hook up an appliance. That is a disaster waiting to happen.

I think don't touch anything related to gasoline, electricity and flammable gases if you don't know exactly how they work.
 
Originally Posted By: Nick1994
Gas can be real dangerous. I just recently put a new gas water heater in at my grandmother's house. Once I was done installing it, I sprayed some soapy water on the shut off valve (very very old) and it was leaking so i had to put a new one in. All I did was turn it off while replacing the water heater.

Everyone, don't forget to spray some soapy water on a valve even if all you did was turn it!


Yes gas valves, the mechanical kind are relubed all the time in the food equipment industry. It's actually part of a good PM program.
 
If you use copper and flared fittings watch out for the flare nut cracking over time, especially if outside.
 
I came home one time and did not have any hot water. Went out to light the pilot and I didn't have any propane. Got it filled and went to light the pilot and there was a huge flare.

The aluminum pilot tube going from the valve to the burner apparently had been touching the steel tank skin. The corrosion ate a hole through the aluminum tube. I was lucky that the hole was just inside the heater otherwise the flames would have go out into the surrounding area.

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