Natural Gas Loss Due To Damage 1

[Gasman324]

We have had a recent increase in the number of incidents involving damage to our gas line. Our ordinances allow us to charge negligent individuals for the gas losses, labor, parts and other incidentals. Up to now most of them were in the ballpark of about 5 to 20 Mcf. Now we have a situation involving a severed riser. The stats are , 25 psi main, 200' of 3/4" steel pipe service line from the tap and 26 hours of blowing gas. I am using the gas loss section in GasCalc 4.0 to calculate the total volume of gas lost. My problem is that when I try to use one of the following standard equations: IGT-improved, Panhandle, Weymouth, Spitzglass I get a significant variance on the flow rate. Can someone please advise which one should be used and why.

 

[BigInch]

Most of them are ONLY for higher pressures (200-800 psi), LARGE diameter (30") and LONG pipelines (miles) at turbulent conditions. Spitzglass is the one to use in your case, as it is for lower pressures. If you have a choice of spitzglass equations, use the one for systems over 1 psig. It is usually the second choice.

"I think it would be a good idea."
- Mahatma Gandhi (1869-1948),
when asked about Western civilization

 

[chicopee]

Gandhi' reply should have been "I think it would be a great idea for India where so much of a cast system and poverty exist"

 

[MJCronin]

Gas....

With a severed supply line, I believe that you may have "choked flow" conditions..???

What is the supply pressure ?

If you have choked flow, then the "standard equations: IGT-improved, Panhandle, Weymouth, Spitzglass probably do not apply..

Back to the engineering "Koran" for this case....Crane Techinical Paper #410

My opinion only

-MJC

 

[Latexman]

With 200 feet of 3/4" line between the main and the sever, it's probably not sonically choked, but is frictionally restricted compressible flow. I'd recommend Equation 3-20 in Crane TP 410.

Good luck,
Latexman

 

[athomas236]

If I was the person who damaged the pipe and I looked at this thread, I would not pay for any gas on the basis that you are not able to demonstrate, beyond reasonable doubt, how much gas had been lost.

Regards,

athomas236

 

[DonPhillips]

Assuming the "ordinances" are laws and the penalties are criminal, then beyond a shadow of a doubt is the standard of proof. If the penalties are civil fines, then the burden of proof is a preponderance of the evidence.

Don Phillips

http://worthingtonengineering.com

 

[Latexman]

If I was getting paid as an expert witness in a criminal or civil trial on this, the person who damaged the pipe would definitely be paying for the lost gas.

Good luck,
Latexman

 

[athomas236]

In the UK the system is a liitle different. Both parties would appoint expert witnesses who are both independent of the parties although paid by them. The experts would then meet and try to agree on the quantity of gas lost. If the agree then that matter is closed and is not raised in court. If they cannot agree then the court decides based on the evidence of both experts.

The court would then decide on what if anything should be paid not the experts. Thats my experience anyway.

Regards,

athomas236

 

[BigInch]

Its more or less the same in the States too. Dispute resolution outside the courts is encouraged. If it makes it to the court, the experts give "expert testimony" and the court/jury takes that into consideration and awards damages based on the weight of all evidence heard.

If you were plowing a field, which would you rather use? Two strong oxen or 1024 chickens?" - Seymour Cray (1925-1996), father of supercomputing
***************

http://virtualpipeline.spaces.live.com/

 

[jmw]

If this is a regular occurrence, then it might make sense to put some of these guys penalties ito a loss metering system with upstream and downstream flow meters either side of the normally severed section of pipe. They can then pay for the difference in meter readings.

Interestingly, if I was the latest culprit and you tried to stick me with a bill I might be prepared to challenge that because of the past history and frequency of such events that it is arguable that there is some negligence on behalf of the owner in its location and protection.
Of course, I don't know the circumstances and maybe you have taken all reasonable care e.g. buried it deep and put in armoured pipes, and maybe someone hasn't checked the plans before digging up the road yet again or something.

JMW

http://www.ViscoAnalyser.com