Distance Between Two Adjacent Pipelines Running Parallel

Hello,

You will need to advise the contents of each pipe. We have codes relating to potable water and sewer lines and required separation, but others here would be focussed on petrochemicals and such.

Our guidelines (whether parallel or crossing) is 500mm separation with appropriate compaction and bedding (Water always above sewer). If parallel, then offset by at least 300mm in the horizontal so the trench is dug with a "bench" for the water line.

For domestic service connections there is a different code.

In oil field it is very difficult to maintain minimum distance between two flowline policy.I have seen plenty of flowline crossing in an oil field .

Thank you for your reply.

Crossing is some what different, and we can find some standards & specs for pipeline crossings, but lines running parallel comes in-contact over the years due to shifting on same supports due to soil erosion, supports failure, etc

"I have seen plenty of flowline crossing in an oil field" Does not mean that is a correct installation

I think if there is problem with corrosion then a requirement to separate the pipelines is already established. The minimum will have to be something that prevents the pipes to come into contact under any circumstances. What environment are those pipes in? Can they move? Why do they touch in the first place? If there is pipe movement is it related to temperature related issues?

As said I don't think you need a standard if there is an eminent need for separation.

Based on your parameters you can define this yourself.

Good luck!

Some standards speaks but in general for example:
ISO 13623:2009 - Piping and pipelines shall be routed such that trip or overhead hazards to personnel are avoided and accessto piping and equipment for inspection and maintenance is not hindered.
The pipelines which i am talking is layed inside forest with lots of rain, some of them can move some cant due to adjacent piplelines installed over the years. As soil erodes under supports due to rain water and in some cases supports sunk into soil,supports twisted to an angle which makes the lines shifted to one side and came in contact. But in some cases poor design also. No they don't have temperature issues.

>0, that's for sure.

contactfarhan

Are you asking about above ground lines or underground lines?

above ground

You don't say whether these pipes are exposed or buried, or if any are insulated.

I would assume that if a gas/oil pipe were buried, then it would be adequately insulated and cathodically protected against corrosion and if, as would appear to be the case, you are able to easily inspect the piping it is likely to be above ground.

There are clear guidelines for separation of buried pipelines which take into consideration such things as surface loading, settlement, current interchange via holidays in insulation, etc, but above-ground piping is generally not affected by these restrictions and Engineers normally design these systems to make them both cost effective to deploy and easily serviceable. Separation is normally kept to the bare minimum with due regard to available space and service requirements.

Consideration should also be given to the effect of possible nearby HVAC electrical cabling creating both induced currents due to magnetic coupling and also breakover current flows in the event of a lightning strike on the HVAC system. This has obvious personnel safety as well as property ramifications These can often be mitigated by the inclusion of suitable bonding techniques, resistive coupling, mitigation wires, transposition of powerline conductors, isolating flanges, Faraday cages, etc.

Even the use of distant electrically powered mining equipment or other large industrial electrical loads can cause high drain currents in local pipelines if they happen to provide a convenient path for stray currents back to the substation. Significant corrosion can occur wherever these currents exit the pipes, ie. cross to another pipe or back to earth.

Many intra-pipe corrosion issues can be controlled simply by equipotential bonding. Pipes won't become anodic or cathodic with respect to each other if they are suitably electrically bonded together. This bonding removes the tendency for one of the pipelines to sacrifice itself to the other. Often, surface corrosion that is evident on pipes and other metallic surfaces, and thought to be the result of intra- service currents is actually the result of localised corrosion caused by small impurities in the metal itself, this in effect sets up small local galvanic cells, and is unable to be controlled by cathodic protection methods and can really only be controlled by eliminating the electrolyte.

Another concern is the possibility of pipe whip in the event of a rupture of a high pressure pipeline which can occur due to a number of influences including fatigue and pressure surge (column separation). This can cause severe damage to nearby services, and inspection must ensure that all high pressure piping is adequately restrained.

Clearance between the outside diameter of flange and the outside diameter of the pipe or insulation 1" (25.4mm)

Clearance between the outside diameter of pipe flange or insulation and structural 2" (50mm). Any seismic issues?

where there isn`t much clearances. Like submarines or navy vessels the clearances between pipe is done by calc`s Blast deflects. typical 2" spacing of OD to OD.

As i said its above ground pipelines carrying crude from well head to plant.

No high temperature issues

laid in rain forest

humid environment

All I can add to what has already been stated, is you have your work cut out for you!

You must correct the touching pipes, supports etc. with a freshly engineered system to avoid these erosional shifts as much as possible, but also will need to take a fresh look at cathodic protection in these systems, as touching is usually a point of charge transfer between pipe systems that exist at different electric potentials, and the failure can be a real catastrophe.

Arrangement and positioning are important factors in

the layout of a piping facility. Space is limited. Area and

boundary limits force conservation of space. Arranging

equipment throughout the unit in an orderly and sequential

fashion is a necessity. Therefore, proper spacing and

arrangement of pipe in the pipe rack requires special

attention. A pipe rack has a defined width; therefore,

working within the allotted space makes spacing crucial.

Not only must pipe be arranged to take up a minimum

amount of space, but allowances should be made for any

pipe that might be added in the future.

Line spacing dimensions are based on a clearance of

1" between the outside diameter of the largest flange and

the outside diameter of the adjacent pipe. The minimum

spacing between any two lines is 4". If either of the lines

is insulated, the thickness of the insulation must be

added. When lines are placed adjacent to a wall, column,

building, or other structure, a minimum clearance of

2'-0" is required from the outside diameter of a flange.

Pipes having orifice flanges also require a minimum

clearance of 2'-0" on either side of the pipe.

This issue could be related to thermal expansion.

If you are inspecting this system you need to write this in your report. This can be a problem down the line. without seeing, the problem may stem from initial planning for heat expansion in the design phase.

If they are using U-bolt type of hangers or the clamp type, the spacing will be different

valve handwheel min 3" apart and stagger

if used, you need spacing for heat tracing

if electrolytic is a problem that should have been noted on the installation drawing and adjusted accordingly

After reviewing may codes and design criteria of various company's

Most of the company design details show 1" the 2" apart for take down joints.

MSS.ABS,API,NFPA,ASTM.ASME.ANSI ASHRAE, ARCO,AWS,IEEE.ISA. IMO, ISO NAVSEA,NAVSHIP,NESC,SMACNA,SNAME,UL,UBS,USCG. They mostly stated the safey of the design, "the best practive" "maintainability and serviceable"

It's hard to find a regulatory body stating the requirment space between piping, endless it's an safety issue and the required spacing is applicable to that system, than they should had flagged the issue during drawing views or noted

I know the navy does due to deflections of the vessel and blast deflection conditions

Thanx Mark...it was explicit enough.

If they were needing painting after installation then there needs to be enough room for the paint brush.

If they need insulation after installation then the minimum distance needs to allow for two thicknesses of insulation and its finish cover.

If in doubt, consult a qualified Piping Designer.