Re: [MW:20402] MANUFACTURING DEFECT IN PIPES

Good Day,

 

Please provide the applicable code refernce of your pipes purchased and photos for easy refernce.

 

 

Below refernce is from API 5L 45th Edition 

9.10.5 Geometric deviations

9.10.5.1

For other than dents, geometric deviations from the normal cylindrical contour of the pipe

(e.g. flat spots and peaks) that occur as a result of the pipe forming process or manufacturing operations

and that exceed 3,2 mm (0.125 in) in depth, measured as the gap between the extreme point of the

deviation and the prolongation of the normal contour of the pipe, shall be considered defects and shall be

treted in accordance with C.3 b) or C.3 c).

9.10.5.2For dents, the length in any direction shall be ≤ 0,5 D and the depth, measured as the gap

between the extreme point of the dent and the prolongation of the normal contour of the pipe, shall not

exceed the following:

a) 3,2 mm (0.125 in) for cold-formed dents with sharp-bottom gouges;

b) 6,4 mm (0.250 in) for other dents.

Dents that exceed the specified limits shall be considered defects and shall be treated in accordance with

C.3 b) or C.3 c).

9.10.6 Hard spots

Any hard spot larger than 50 mm (2.0 in) in any direction shall be classified as a defect if its hardness

exceeds 35 HRC, 345 HV10 or 327 HBW, based upon individual indentations. Pipes that contain such

defects shall be treated in accordance with C.3 b) or C.3 c)

9.10.7 Other surface imperfections

 

Other surface imperfections found by visual inspection shall be investigated, classified and treated as

follows.

a) Imperfections that have a depth

≤ 0,125 t and do not encroach on the minimum permissible wall

thickness shall be classified as acceptable imperfections and shall be treated in accordance with

Clause C.1.

b) Imperfections that have a depth

> 0,125 t and do not encroach on the minimum permissible wall

thickness shall be classified as defects, and shall be dressed-out by grinding in accordance with

Clause C.2 or shall be treated in accordance with Clause C.3.

c) Imperfections that encroach on the minimum permissible wall thickness shall be classified as defects

and shall be treated in accordance with Clause C.3.

NOTE "Imperfections that encroach on the minimum permissible wall thickness" implies that the portion of the

wall thickness that is beneath the surface imperfection is less than the minimum permissible wall thickness.

 

 

Thanks and Best Regards,

 

G.Murali krishnan
Mob : +966-501487307
Saudi Arabia

On Wed, Mar 19, 2014 at 4:57 PM, Sampath Kumar <skthatham@gmail.com> wrote:

Dear Experts,

We have around 22 CS pipes,[FIRE WATER Line]of size 20"Sch 20 12 mts in length.The pipes are having some manufacturing defect which is running throughn out the pipe.The EPC people wanted to directly accept saying that it will not have any major impact as this is only a fire water line.[It is a pipeline project,construction of Oil storage tanks & Jetty]

Our view is that it can not be a mill scale.If it is a mill scale,it should have gone after the blasting.Other view is it can not  be a rolling defect also.Pitting is ruled out.

Our suggestion to the EPC to do spot blating,If necessary do  grinding,check the thickness and then we will come to conclusion.

Now the question is  Can we reject the total quantity of the pipes on the grounds saying that it has got manufacturing defect.On what basis it can be done.

Why should we accept the pipes?If we have to accept, on what basis.?

What will be the final consequeces If it is accepted directly with out carrying any tests.?

Is there any other way or test we have to do on these pipe.

Pls reply back at your earliest.Kindky give me all the options.

Thanks & Regards

Sampath

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