Painting on Flange surface 1

[starships]

Hi Gents,

We're facing very difficult situation for Aramco project as below.
Following is the requirement of SAES-H-002.
5.2.9 "The internal coating shall be extended up to the face of flat-and raised-face flanges that will not be in contact with the gasket. The coating applied shall be machined and ground to ensure that the surface is levelled properly and to avoid misalignment of gasket".

Status is as below.
1. Piping fluid is sea-water.
2. Internal surface of piping has been coated with FBE to prevent corrosion which will be caused by sea-water.
3. Flange surface is not coated.
4. Gasket does not cover up the whole surface of flange.
5. During commissioning, it has been found that the area (which is not covered with gasket) is corroded by sea-water.

Based on Aramco requirement aforementioned, client is requiring the area shall be coated or covered with new gasket.
Thus, we need the interpretation on Aramco requirement and to share your experiences in this case.

Thanks in advance

 

[LittleInch]

This is always an issue when you internally coat steel pipe - what do you do at the flanges??

One issue is that there is a sharp corner on many flanges which becomes a weak spot for the coating and I've seen previously that the flange edge requires profiling to a radius of~5mm to avoid this.

However most times I would then either get a duplex flange and internally coat up to the edge or face the flange with something like Inconel 625.

It is very difficult to do what the specification says in practice as you don't want the coating on the flange faces in contact withe gasket which means somewhere you have an edge of the coating in contact with seawater and this is where it corrodes. However internal pipe coaters should be familiar with this.

Some photos would help.

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

 

[Dhurjati Sen]

Dear starships,

Do what the client is asking for. Either apply paint to the corroded area else go with a wider gasket.

Regards.

DHURJATI SEN

https://www.nace.org/people/dhurjatisen