Flange condition assessemnt 2

[mariolucas75]

Dear forum,

Could you please advise on flange assessment...
Well there is a flange face assessment criteria:

"ASME PCC-1 Appendix D - Guidelines for allowable gasket contact surface flatness and defect depth"

That tells to what extent the serration rings can be damaged.

Is there a criteria about the thickness of flange? For example there is a flanged connection, corrosion is running around it and to perform the assessment of the flange... the thickness of it ?

Another question how would you assess the flange given in attached example ? or what would be your recommendations ?

Thank you so much

 

[LittleInch]

The flange needs to meet the dimensions specified in the appropriate flange specification. They tend to have very little or no corrosion allowance.

Get a shot blasting gun on it and paint it properly. The outer portion is only really there to hold the bolts in place.

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

 

[mariolucas75]

And the fact that gasket between the flanges turned almost into debris? Is it a kind of concern or untill when it is not worthy to worry?
And in general deterioration of flange faces happen from the inside or the outside ?

 

[LittleInch]

The bit that's keeping the contents in is still working.

It's not in great condition, but if you don't want to totally remake it.

They can do both, depends what's on the inside. RTJ flanges can corrode badly if not protected in the ring groove, but RFs are usually better.

Some companies employ flange protectors to stop corrosion in that space between the flanges where it is very difficult to get at and keep clean and painted.

What size, rating and gasket type do you have there?

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

 

[mariolucas75]

Flange SA105N 6" 300# W.N.R.F.

Does this bring more precise view ?

 

[r6155]

These flanges will have to be dismantled. It is not a good look on a plant, it creates a feeling of insecurity. Paint is no longer enough.

Regards

 

[r6155]

I agree with LittleInch: “What size, rating and gasket type do you have there?"
You say "Does this bring a more presise view?"
I add more information: design pressure/temperature? fluid? allowable corrosion?
NPS 6 class 300 is not the same as NP3 class 900, the consequences are different in the event of an accident.
How many more days would you like to continue like this?

Regards

 

[mariolucas75]

Dear r6155 and LittleInch:

The flange is Flange SA105N 6" 300# W.N.R.F.
The gasket is Spiral wound 316LSS / Graphite
Service is glycol ~ 15 bar ~ at 90 C ....

What would be your opinion?

 

[r6155]

For these conditions, class 150 is fine, I don't know why it is class 300.
I confirm my previous comments.

Regards

 

[LittleInch]

Get it cleaned up and have another look, but there's nothing I can see which would cause me to change my post above.

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

 

[A8yssUK]

Firstly, why doesn't anybody use washers, they cost nothing!!

Secondly... I'd worry that the corrosion is eating the bolts now, they need to be checked.

 

[LittleInch]

It kind of looks like someone has filled in the gap with some gunge. And a bit odd its only one flange which has rusted on the surface quite badly, but get the flay stuff off and dig out the fill material and see what you've got.

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