Water Main Parallel to Structure Distance

[2close]

What is the minimum safe distance between a Water Main running parallel to a Buliding Structure with a basement?

 

[rconner]

One would think that a sort of common sense should be employed where this is practical e.g. to allow safe room for unimpeded digging trenching and pipe laying etc., and if there are any problems with installation or testing of new construction also to minimize damages to either structure etc. However, if you must or have very good reason to get very close e.g. to buildings, I don’t know what should govern in your particular area/application -- however, I do know ANSI/AWWA C600-05, Installation of Ductile-Iron Water Mains and Their Appurtenances states,
“ 4.3.2.5 Rock conditions. When excavation of rock is necessary, all rock shall be removed to provide a clearance below and on each side of all pipe, valves, and
fittings of at least 6 in. (150 mm) for nominal pipe sizes 24 in. (610 mm) or smaller and 9 in. (230 mm) for nominal pipe sizes 30 in. (762 mm) and larger. When excavation is completed, a layer of appropriate backfill material (see Sec. 4.2.5) shall be placed on the bottom of the trench to the appropriate depths, then leveled and tamped.”
The above passage is immediately followed by,
“4.3.2.5.1 These clearances and bedding procedures shall also be observed for pieces of concrete or masonry and other debris or subterranean structures, such as masonry walls, piers, or foundations that may be encountered during excavation.”

Of course as previously inferred other considerations or authorities might supersede these requirements e.g. another section of this same standard states, “4.3.1.3 Clearance. When crossing existing pipelines or other structures, alignment and grade shall be adjusted as necessary, in accordance with the contract documents, to provide clearance as required by federal, state, or provincial, and local regulations or as deemed necessary to prevent future damage or contamination of either structure.”

 

[BigInch]

Oil and gas pipelines use a 12" minimum clearance to any foreign object. It might not be a "minimum safe" distance, which is basically left up to the engineer to determine what that may be.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[cvg]

I think I would be concerned about the possibility of future leakage, possibly causing water to enter the basement or weaken the foundation. In that case, keep it farther away from the building and maybe provide encasement, sleeve, restrained joints or other methods to limit potential leakage.

 

[BigInch]

Let's ask how large a diameter this water line actually is?

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[bimr]

There is no universal standard safe distance.

First of all, what is the easement for the water pipeline? Does the easement actually go all of the way to the building?

A rule of thumb is probably 10 feet minimum. For example, most petroleum companies ask that you stay 10 feet away (side to side) horizontally and 2 feet vertically.

You should address the future requirements of maintenance. If the pipe is deep, is it possible that you may undermine the building when you are doing maintenance in the future?

You also should be concerned should the pipe leak. The leak is probably going to run along the length of the pipe in unconsolidated material. If the pipe is close to the building, the leakage may end up in the building underdrain.

You also have to be concerned about the soils. How are you going to compact the soils adjacent to the building without damaging the building foundation? Note that water mains are unusally unrestrained pipes and rely on the soil to hold them in place. This is a soils geotech issue as well.