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Natural Gas Explosion

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john mcg

Its not my business and I have very little knowledge of such systems, but it seems to me that regulation and safety mechanisms would be/should be well upstream of homes. If not, someone didn't have their thinking caps on.

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oak stob
20 minutes ago, Cooter Brown said:

From this and other posts you've made you seem to be from the energy industry so your perspective is appreciated.

 

Last year I smelled gas outside near the street and called the gas co.  It turned out to be a junction of some sort in a neighbor's yard.  From talking to the guys fixing it, I got the impression, which might be wrong, that the main line pressure wasn't that high to begin with and was stepped down even more before it went to each house.  Of course I might have misunderstood.  Is that more or less what happens?

 

It'll be interesting to hear what they determine the cause to be.

 

I’m more in the peeing on a location stake, drilling and production than consumer/industrial gas supply systems but, to my knowledge, Dominion runs about 4 ounces and then the house regulator drops it again.

Dominion’s line pressure tho will vary from their original purchase point, in transportation perhaps and then on to the end user.

As long as the volume is sufficient for the draw, which is all based upon pressure, line diameters, orifice size and usage all goes well.

 

Not sure if that answers your question.

 

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john mcg
9 minutes ago, oak stob said:

 

I’m more in the peeing on a location stake, drilling and production than consumer/industrial gas supply systems but, to my knowledge, Dominion runs about 4 ounces and then the house regulator drops it again.

Dominion’s line pressure tho will vary from their original purchase point, in transportation perhaps and then on to the end user.

As long as the volume is sufficient for the draw, which is all based upon pressure, line diameters, orifice size and usage all goes well.

 

Not sure if that answers your question.

 

At what point then would the volume be changed?

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oak stob
27 minutes ago, john mcg said:

Its not my business and I have very little knowledge of such systems, but it seems to me that regulation and safety mechanisms would be/should be well upstream of homes. If not, someone didn't have their thinking caps on.

....

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oak stob
3 minutes ago, john mcg said:

At what point then would the volume be changed?

 

I don’t understand your question, John.

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john mcg
6 minutes ago, oak stob said:

 

I don’t understand your question, John.

As you correctly state, the variable dynamics in such a system of flow are volume, pressure and diameter of lines and orifices.

At what point in the system would/could volume be changed?

I have no specific knowledge and am just trying to reason it out.

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VizslavsBird
11 hours ago, Flairball said:

It shouldn’t go unnoticed that the union gas workers have been locked out for months, and their jobs being done by scabs. There have been numerous smaller problems throughout the area, but now this. Looks like it would have cost management a lot less if they had just settled a contract with the union. 

 

Wow, thought this was a POLITICS FREE board?

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stripersonfly

I live in North Andover.  Kind of a crazy scene last night.  My neighborhood is quite some distance from the one that was affected. Luckily, it was easy enough for me to shut off the gas to my house as well, so we never felt the need to evacuate.  If you do not know how to shut off your gas, it is very easy to do.   A quick google will get you the info you need to know, and just take a moment to locate your gas meter and the shutoff valve located close to it.  It is a good thing to know how to do. 

 

In regards to the union question, the company who locked out the gas workers was National Grid.   The system in question here belonged to Columbia Gas, and to the best of my knowledge it was being serviced by union personnel and it still failed.  Reports are all over the place but supposedly they were 'updating systems in the area' yesterday.  Still unclear what caused the overpressure, but NTSB is starting an investigation.  Interesting that the FBI are also involved, but that may be standard on a case like this. 

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john mcg
2 minutes ago, stripersonfly said:

I live in North Andover.  Kind of a crazy scene last night.  My neighborhood is quite some distance from the one that was affected. Luckily, it was easy enough for me to shut off the gas to my house as well, so we never felt the need to evacuate.  If you do not know how to shut off your gas, it is very easy to do.   A quick google will get you the info you need to know, and just take a moment to locate your gas meter and the shutoff valve located close to it.  It is a good thing to know how to do. 

 

In regards to the union question, the company who locked out the gas workers was National Grid.   The system in question here belonged to Columbia Gas, and to the best of my knowledge it was being serviced by union personnel and it still failed.  Reports are all over the place but supposedly they were 'updating systems in the area' yesterday.  Still unclear what caused the overpressure, but NTSB is starting an investigation.  Interesting that the FBI are also involved, but that may be standard on a case like this. 

Glad you are safe and sound. Thanks for the report and information. My daughter has friends in N. ANdover, so there were a few minutes last night where we were nervous.

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oak stob

John, a company tasked with gas supply, monitors usage and calculates/estimates changes, which these days are normally a continual increase from homes or factories coming on-line and so on....as I’m confident you know.

 

So, as a need develops, seasonally or not, they pull MCFs from gas storage fields, etc. or work to find or purchase new sources of product.

These days, natural gas is in abundance.....getting it into the system for folks, follows demand....quickly or slowly, just depends...easily is the norm today.

Not sure if that does it. 😊

 

 

 

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MAArcher

It was a long sleepless night last night.  I'm out of town for work and my wife and kids were just a couple miles from the closest fire and we get gas from Columbia. 

 

I'm in awe of the fire department's.  How did they get that many fires under control, during rush hour in some of the most traffic congested area of the country, while 100k+ people are told to evacuate?  Bravo.  

 

I installed the gas lines in my house myself.  I told my wife not to shut off the gas because the main valve is the only one in the house that isn't relatively new, if a valve fails it would be that one, best to leave it alone.  I'm assuming if there was overpressue, either old valves in the home failed or gas traveled along the outside of underground pipe lines from a failure at the street and entered the home that way.  Either way the home fills up with gas and when the hot water heater kicks on or the the AC starts up, boom.  I told my wife to open up as many windows as she could.  Natural gas needs a certain concentration to explode and opening up the house can greatly reduce the risk from what I understand.  She has a nose like a blood hound anyway, she'd smell gas way before it was dangerous.  

 

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john mcg
7 minutes ago, oak stob said:

John, a company tasked with gas supply, monitors usage and calculates/estimates changes, which these days are normally a continual increase from homes or factories coming on-line and so on....as I’m confident you know.

 

So, as a need develops, seasonally or not, they pull MCFs from gas storage fields, etc. or work to find or purchase new sources of product.

These days, natural gas is in abundance.....getting it into the system for folks, follows demand....quickly or slowly, just depends...easily is the norm today.

Not sure if that does it. 😊

 

 

 

 

 

 

 

 

Thanks, Oak. So I'm trying to picture a system in my mind and that picture (uninformed at best) suggests failure at multiple places...including at the various homes locations. Kind of a perfect storm thing. What tickles my brain--is why this sort of thing hasn't happened before. Again--I plead ignorance.

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WMassGriff

Retired gas transmission employee. Not totally familiar with low pressure systems, but I surmise a pressure overprotection device failed on the supply. Not sure what would cause override of individual meter protective devices. I know we employ multiple monitored/maintained devices for high pressure and I assume they do too. 

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oak stob
25 minutes ago, john mcg said:

Thanks, Oak. So I'm trying to picture a system in my mind and that picture (uninformed at best) suggests failure at multiple places...including at the various homes locations. Kind of a perfect storm thing. What tickles my brain--is why this sort of thing hasn't happened before. Again--I plead ignorance.

 

Yes, just does not make sense to me for reasons such as WMassGriff noted....be good to know whatever findings develop.

 

If there is/are gas leaks, gas easily travels and often from reasons of weather conditions of the moment as well as accumulating with low terrain, movement thru ground conditions and so on. 

 

Valves are unlikey to have failed in this case...they would have been open.

Valves can fail when a home owner tries to shut one that has not been used for a good spell.

More like pressure regulation devices and safety features were involved at several levels, perhaps along with human error...one will see.

 

With an aging infrastructure......best to stay birdy to all around us.

 

 

 

 

 

 

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Flairball
4 hours ago, Felix said:

 

 Wow.   I would venture to guess that there are quite a few non-union members here on UJ.  But never let a good catastrophe go unused. 

 

I think you misunderstand. Nothing wrong with being non-union, until you take the job of a union guy locked out. Then you’re a scab. 

1 hour ago, VizslavsBird said:

 

Wow, thought this was a POLITICS FREE board?

 

Is discussing the structure of employment politics? 

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