New or used pipe?

Date 10-16-2008 16:24

Hi everyone, I have a problem to certify whether or not pipe tested are new or used as it shown in the following pictures that is attached.
the characteristics of the pipes are the followiing :

Nominal diameter : 18 "
Nominal wall thickness :0.375"
Material quality : ASTM A53 Gr B seamless "type S "
the liquid which would flow throgh this pipe line is H2SO4

Theses pipes show defects on the surface which according to me , it doesnt usually show on a new pipe This pipe were maken in accordance with the norm ASTM A53 Gr B. I made both chemical analysis and metallographyc test , Therefore both test follow the norm describe previously.

I would like you to give an opinion about if these defect are frequent in a new pipe or may be it come from corrosion defect.

Thank for your comments.

By G.S.Crisi (****)

Date 10-16-2008 21:09 Edited 10-16-2008 21:14

There's no doubt that the pipes are badly corroded. It's possible that they have never been used, but in this case they were stored in such a manner that strong corrosion took place.
If I were the inspector, I wouldn't allow to use them
Giovanni S. Crisi
Sao Pulo - Brazil

By jon20013 (*****)

Date 10-17-2008 03:09

Quibo, I have seen similar indications on new pipe many times. The key is the depth of the indications or rather, the remaining wall thickness. Do you have that information? Professor Crisi makes good points regarding storage but to do yourself a favor, check remaining wall thickness and see if it is within tolerance.

By gwg

Date 10-21-2008 02:20

I have seen this type of internal corrosion damage on pipe that was not properly stored - capped.

By G.S.Crisi (****)

Date 10-22-2008 16:57

jon,
From a purely technical point of view, you're perfectly right. If the wall thickness is within tolerances, technically the pipe can be used.
Now, from a "good engineering practice" point of view, I think that the pipe can not be used. If you were the owner of the plant, would you allow the contractor to install a pipe like that?
Giovanni S. Crisi

By jon20013 (*****)

Date 10-22-2008 17:49

Giovanni, while the indications "look" horrible, it's impossible for me to guess at their depth. So, while the appearance may be poor, if it is within specification, on what basis can I reject? The person posting has not indicated the depth so it's impossible to say.

By gwg

Date 10-23-2008 15:31

"Now, from a "good engineering practice" point of view, I think that the pipe can not be used. If you were the owner of the plant, would you allow the contractor to install a pipe like that?"

Not necessarily. Depending on service conditions, the pipe could be evaluated and dispositioned for use.

By js55

Date 10-23-2008 16:12

I'm with jon and gwg on this one. If the min wall has not been violated a blending can dress up the appearance and the pipe is perfectly viable and code acceptable, given disposition as gwg states.
I'd suggest UTT.

By CWI555

Date 10-27-2008 11:18

He's already stated the service, that being H2SO4/sulfuric acid. In light of that, to my mind, there are more considerations to this than simply the wall thickness. The nature of what corroded it to begin with should be addressed. Depending on the nature of the corrosion, my concern would be how the sulfuric acid would interact with any remenants of the originating corrosion mechanism. Simply sand blasting may or may not have been enough to remove all traces. Based on grade etc listed, they can lose .047" from nominal (3/64th)
The shadows on the corrosion face edges imply something deeper than that.

All in all, If I saw something like that, I'd sure be looking for any valid reason to get rid of it given the service of sulfuric acid. If it were a water line or something like that, I probably would'nt worry about it if it's min wall wasn't violated, but acid?? Somebody could get hurt if it fails, and I sure wouldn't want to be the engineer who ok'd something like that if it failed with pictures like that floating around.

My opinion for what it's worth,
Gerald

By vittorio (*)

Date 10-28-2008 11:18

In my opinion this pipe has been used or it has been stored with a lot of water inside. We can't say for sure how much is the depth pf the defect but it's clear, i mean for me, that this is a corroded pipe.
There are two considerations:
1) there must be, i don't know the number, an ASTM standard that define the limits of acceptability for a "new" pipe in terms of defects... like for example the API 5L which specify the maximum depth of defect..and how to inspect API 5L8.
2) are you sure that this materials is acceptable for your service, H2SO4, in terms of corrosion resistance? What is the conc, temp and velocity of the H2SO4?

My suggestion is : Search for the ASTM standard and make a corrosion assesment for your service.

regards

Vittorio