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Join Date: Jun 2007
Posts: 72

Hydrostatic Testing for Sub-Sea Pipelines

07/10/2007 9:15 AM

I was reading in the OSF101 code about Hydrotesting, and here is what i found out,

1) For pipes with reduced utilisation of the wall thickness, the test pressure Ph maybe reduced as permitted in section 5D 400.

2) The test pressure Ph for all other pipes shall, in situations where the seal is made on the inside or the outside of the linepipe surface be conducted at the lowest value obtained by utilizing the following formulae:

Ph= (2.tmin / (D - tmin) ) . min[SMYS. 0.96; SMTS . 0.84]

3) In case where the specified corrosion allowance restricts the test pressure due to mill testing capacity, the test pressure shall be Ph = 1.5 Pdesign

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I aslo have read in the other hydrotesting thread about the 1.5 factor for the piping hydrotesting so i was wondering about the seal inside or outside of the linepipe surface in #2, what does it mean ?

also what and when is the specified corrosion allowance restricts the test pressure due to mill testing in # 3 ...actually what does all this mean ?

once again what is a mill test ? What does the word mill mean ? millimeter ? (obviously not)

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Guru
Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

Join Date: Feb 2007
Location: Cairo, Egypt
Posts: 1733
Good Answers: 245
#1

Re: Hydrostatic Testing for Sub-Sea Pipelines

07/11/2007 12:16 PM

My dear Primavera

A. Pipeline & Linepipe.

There is a difference between pipeline and linepipe. Pipeline is a complete pipe line to be constructed and joined, and consists of linepipes, fittings, flanges, supports, valves, ... etc. Where Linepipe is the unique pipe or pipe segment produced at mill and used in construction of a piping system or pipeline.

B. Mill.

Mill is the factory where the linepipe is produced and hydrostatically tested (called mill test) and prepared for shipping to users, piping fabricators and erectors.

C. Seal inside or outside of the linepipe surface.

At mill, during hydrostatic test, there are two methods to plug the 2 ends of linepipe bu using a test rig designed for hydrostatic tesing of linepipe:

1st is carried out by plugging the ends using a sealing from inside of the linepipe surface.

2nd is carried out by plugging the ends using a sealing from outside of the linepipe surface.

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Anonymous Poster
#2
In reply to #1

Re: Hydrostatic Testing for Sub-Sea Pipelines

02/21/2011 11:23 PM

hello sir , can you suggest me where can i get the information of this procedure:

1)flooding,gauging,hydrotest,dewater and N2 purging prosedure

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Guru
Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

Join Date: Feb 2007
Location: Cairo, Egypt
Posts: 1733
Good Answers: 245
#3
In reply to #2

Re: Hydrostatic Testing for Sub-Sea Pipelines

02/22/2011 11:05 PM

May be you find good information here: http://search.4shared.com/q/1/SubSea%20Pipelines%20.

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