DISTANCE BETWEEN UTILITY PIPES 5

[allie075]

Hi guys,

Does anyone know what the setback distance between a gas line and sewer line should be? Recently, we encountered a gas line about 2 inches away from one of our sewer lines.

We know the sewer line was there before the gas line so they infringed on our space. However, we can't find any written reference for suitable spacing.

Please help if you can.

Regards,
Allie

 

[diarmud]

Check with your local building code officials. We space them 2 feet apart because there is the possibility of the gas line leaking and gas getting into the sewer line.

2 inches is not enough.

Let us know how you make out.

Regards,
Dermott

 

[GoldDredger]

Usually not an issue between those two ulilities, sewer often have much more depth as it is gravity dependent (most times).

What size is the gas and sewer, is the gas a trunk line or a lateral line?

I've mostly heard of separation requirements between sanitary and water, to reduce contamination risk, usually 10' horizontally and 18" vertical at crossings with sewer below (among other caveats). Never heard of gas/sewer separation requirements.

I would suppose the separation should be great enough to promote individual replacement/repair should one or the other break.

2" is way too close..

 

[civilman72]

"I would suppose the separation should be great enough to promote individual replacement/repair should one or the other break."

GoldDredger got this one right. Utility companies that I deal with "recommend" that there is a 10' (horizontal) separation between shallow and deep utilities. They want to avoid hitting a shallow utility line will digging deeper to repair a water or sewer line.

But this is simply a maintenance issue, and not necessarily a set standard - the only two I'm aware of that are somewhat set-in-stone are electric and gas, and water and sewer should be separated by 10'.

 

[GoldDredger]

I hope that isn't inferring I got the 'other ones' wrong..hehe

 

[bimr]

There probably is not a specified distance required by code. The municipality may have a specific requirement, you will have to check the local building code.

Here is a general guideline. Installation of gas lines and components using sufficient separation distance and appropriate pipe protection layering to minimize potential interference with other underground infrastructure.

A reasonable separation for a parallel pipeline is 18". The separation between the gas pipeline and other facilities must be sufficient to allow for maintenance activities on both utilities. Be sure to check local regulations for the minimum separation distances between the gas pipeline and
the other facilities.

AGA recommends 12" of vertical separation and 3 feet when drilling parallel:

http://www.aga.org/NR/rdonlyres/234EB85F-7993-4D24-B79C-72EAA4B1E825/0/0412DRILLINGGDLNS.pdf

Here is a design guide that may be useful:

http://www.doh.wa.gov/ehp/Ts/WW/wp-pipeline.pdf

 

[CPENG78]

Allie075,
Can you provide more information with regards to you scenario? 2" is certainly too close regardless of whether it is a service or a trunk line. I would think that you would not only consider your pipe to pipe separation but more your trench wall to trench wall separation so that standard trench sections can be replaced if maintenance is required. Sometimes the space is just not phisically available and then you would have to consider other alternatives such as thicker wall pipes, pipe concrete craddles, etc along with special permits from the utility company or agency which allows you to break from the standard.

I ran the question by our joint trench designer here in our office and he mentioned that here in California PG&E standard reads 3 ft separation from edge of gas pipe to edge of any wet utility pipe. However he has encountered situations where the PG&E field inspectors interpret this as 3 ft separation from trench wall to trench wall.

 

[dicksewerrat]

Are you the owner of the right-of-way? and the sewer? Who told the other guy that he could put his line in? And where was he told to put it? He may be moving thayt line.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[allie075]

Hello everyone,

Thanks for all of your comments. Bimr special thanks to you for the links you posted. We would prefer to go with the 10 feet separation suggested by GoldDredger but many of the roads here are too narrow for that. We seem to be heading toward 6 feet and negotiations are ongoing with the gas folks.

Thanks again!

Allie.