undergound gas leak?

[newtonb]

Our neighborhood is currently being dug up by AT&T to install cable modem. I have heard the contractors already hit a gas line once. The gas company informed one of the neighbors that if the contractors even nicked the anticorrosive material on the gas line, the line could have a leak in a year or so.

My question is the following: (I am not a firefighter) If we have a gas line undergound which begins leaking, how serious of a problem is this?

thanks for any info.

[This message has been edited by newtonb (edited 02-22-2001).]

[CAPTAIN WHO]

newtonb: An underground gas leak can be a massive problem. We had an incident about 10 years ago. Failed union on an underground main. We had a post office approx 80 ft from where the leak occurred. This was a 2000 sqr foot concrete and brick building single story. The basement was fairly small and contained only a Mechanical room which once the ground became saturated started leaking into the basement of this structure.

Once the levels became high enough the basement exploded when the furnace kicked in. Witnesses in the apartment building across the street stated a mushroom style fire ball came from the building approx 75 ft tall.

Then the concussion was so severe that due to the vacuum caused by flying building debris the fire ball was sucked back into the remaining hole. The front door and Postage stamp machine cleared the service station across the street and landed 2 backyards behind. Debris from the building (not to mention mail) were found in a 2 block radius of the building site.

The original building site was pretty much cleared and left a hole 15 feet deep and 75 feet across. All buildings around and or across the street were severely damaged. Houses shifted off their foundations, Doors and windows blown in. I lived 3/4 of a mile from the Post Office. I thought someone crashed a car into the side of my home. The blast rattled windows 8 miles away and was heard for many more.

We were lucky no one was at the post office or on the street. The explosion occurred at 00:05. 500 people were later evacuated. The night Janitor was supposed to be there. He was on his way from a nearby town, decided he was to tired and went home, with the intention to return to finish up at 06:00. The Postal delivery truck drops off around midnight also. He should have been inside but his Highway tractor broke down 30 miles out of town and was 3 hours late. One person had entered the post office at midnight to get his mail after work. Thought he smelled gas but wasn't sure. Just pulled into his driveway when the explosion occurred never had the chance to call anyone about it. We were 19hrs on scene.

This can be Nasty. The only thing that stayed in the area was the 3 ton safe. It was at the bottom of the hole.

We made coast to coast news coverage for a couple days.

Andy Holzli
Captain, Blackfalds Fire Rescue.

[This message has been edited by CAPTAIN WHO (edited 02-22-2001).]

[Captain Gonzo]

My Department had a house explode from a natural gas leak back in 1983. The fire went to two alarms and completely destroyed the house. Upon investigation, there had been an odor of gas in the neighborhood for a week or so, but nobody thought it was dangerous, so it went unreported!

Most of the gas lines installed today are made of plastic...no corrosion problem. In Massachusetts, we have DigSafe...anytime any one is going to dig anywhere, they are supposed to call DigSafe, who will come out within 24 hours and check the area for underground gas lines, utilities, water mains, etc. There is no charge for the service.

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Firefighters: rising under adverse conditions to accept the challenge!
Captain Gonzo

[newtonb]

Thanks so much for the information. I will have to research this more and keep up with it. The underground gas and phone lines have been marked for the neighborhood, and apparently the contractors went through the gas line anyway. We are on in the foothills so they have to frequently use jackhammer type equipment to get through the rocks anyway. Don't know if that caused additional problems or not.

[RJE]

Tulsa had one a couple of months ago. Power company hit an unmarked line (previous owner ran gas to his detached garage to run a portable heater for his workshop). Resultant leak ended up leveling the house. Several injuries.

Then again, there's Hutchison, KS!

[Calvertvolunteer]

There was a house in Silver Spring MD that was obliterated recently. Gas built up and leveled the place. Condemmed another half dozen houses. You need to get this fixed immediately

[CollegeBuff]

If I remember correctly, there's been three house explosions in as many years in my homestate of RI. Two in Warwick. In both incidents, the SAME construction company was out on the street digging, and were found responsible during the investigation! Two houses completely obliterated. We're talking shards of glass inbeded two inches deep in trees across the street.

[newtonb]

thanks again for the responses. I have since found out that it is standard procedure for the contractor to contact the fire department and gas company once they hit a line (I guess they have done it before). The gas company came out an fixed that one break.

[newtonb]

Another question on this topic, if you don't mind. Is there any detector on the market which alerts someone to natural gas buildup? (ie - does a CO detector catch this?)

[Lewiston2Capt]

Most definitely. What you are looking for is a combustible gas detector which will give you a reading in %LEL (Lower Explosive Limit). Or most natural gas distribution companies will have a combustible gas meter calibrated specifically for natural gas.

[Drewd]

It was my department's territory that AT&T hit a gas line while running new cable. It's been almost a year now. Not only did they hit a high pressure gas line, but a sewer line as well. This allowed the gas to fill the surrounding houses with gas. Two of them exploded. It's truly amazing no one was killed.

[This message has been edited by Drewd (edited 02-27-2001).]

[newtonb]

For clarification, is a CO detector a combustable gas detector? Are other people concerned with AT&T (or whoever) upgrading the cable everywhere so that cable modem access is available to the masses?

[This message has been edited by newtonb (edited 02-27-2001).]

[RJE]

Two points. First, a CO detector is not a smoke detector, nor is it an explosive gas detector. If you're concerned, you need all three. There may be devices that have multiple detectors in one housing (I have a combination heat/smoke/CO in my own home, but it won't detect explosive or combustible gases.

Second, it doesn't have to be AT&T, nor does it have to be for "cable modem" access. A recent house explosion in Tulsa was caused by the homeowner with a rented "ditch-witch" digging a trench for a "french drain" lawn drainage system. He hit an unauthorized gas line laid by a previous owner run to a detached garage for a ceramics kiln that had been capped after the kiln was removed. He didn't break the line, but pulled it enough to break it at the "tee" under the house. It exploded, leveling the house, several hours later.

[newtonb]

thanks again for the info (quite educating for the lay person). I have both smoke detectors and CO detectors in the house. I will call the gas company about the combustable gas detectors. I always wondered the significance of why the gas company continually sent out reminders to locate the gas lines before homeowners did any digging...