Regarding hydrotest of pipline 1

[purode333]

Dear sir,

We are doing the piping work as per B 31.3.

i have two queries
1) What will be the longest length of pipe line allowed for hydrotest.
2) what will be the allowance in between the working temperature as per secification and hydrotest temp.

Example: working temp of line is 37 degree celicus, then at what temp. we will allow to do hydrotest.



Regards
Prasad

 

[LittleInch]

I know it is semantics, but pipelines are not designed to B 31.3, but piping is.

I don't believe there is any restriction on length or volume. You can, in theory, test hundreds of kilometres of pipelines ( not normally practical due to elevation differences).

At 37 C operating you can test to the same pressure at ambient temperature. B 31.3 has a section where you vary the test pressure at ambient test conditions to match the pressure if the operating temperature is greater than about 37 Deg C where de-rating of the material applies.

Pipelines designed to a pipeline code are different to piping. You need to read the relevant section of the correct design code.

What are you hydrotesting?

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[mk3223]

It doesn't limit the length of the pipe by the Code for doing the hydro. As concerning the schedule and resources of the manpower, available water, etc., you may consider to break up the pipe or pipeline into sections for the hydro tests.

 

[racookpe1978]

to illustrate the problems mentioned above. If you are hydrostatically testing 31 kilometers of pipeline, how are you going to inspect it fast enough while keeping the temperature steady so the hydro pressure remains correct in the band? If a leak is "detected" by rapid loss of pressure, how are you going to find the leak over that length of pipe?

 

[purode333]

Dear sir,

I want to know a what we applies as per "Standard good engineering practices".

I think,practically 1 Km is the standard practice to test/inspect max. length during hydro.


Regards
Prasad Rode

 

[LittleInch]

standard good engineering practice is not to artificially include joints or sections not subject to a hydrotest.

As we appear now to be talking about above ground piping? 1000m is a short distance. B41.3 requires that you leave exposed all welds, joints and attachment welds for examination.

If you need to test longer distances either have more people to check longer sections at the same time or walk faster.

It's all about the specific systems - in some cases it makes sense to pressure test spools of 15 to 20m, in other cases ( long pipe runs), you might be able to do 15 to 20km.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.