Spiral wound Gaskets material - SS316 instead of SS304

[Murali-1311]

I'm looking for justification to convince the client for accepting Spiral wound gasket(ASME B16.20)-with SS316 windings/Graphite filler, SS316 inner & outer ring in place of actual project requirement SS304.
Client is reluctant to accept changes even after explaining that SS316 fulfills all requirements of SS304 moreover it is a superior grade with higher corrosion resistance due to added molybdenum. Please suggest possible ways to convince the client.

 

[0707]

If the aplication is for high temperature service maybe the client has some reason to be reluctant.

lm

 

[Murali-1311]

It is a skid package for Residue Gas Compressor plant, design temp =max. 200deg.F

Generally does SS304 have any superior characteristics when compared to SS316 ?

 

[MJCronin]

Get a statement from the gasket vendor on why he does not offer the, older and inferior grade of SS anymore.

Have him state how industry has moved on from SS304 to SS316 because there is virtually NO DEMAND for the older grade of metal.

Have him state his reasons for not offering his product in a SS304 configuration

MJCronin
Sr. Process Engineer

 

[EdStainless]

There is actually very little difference in pitting resistance between the two grades, but 316 is slightly superior.
What is the rest of the metallurgy in the system?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[0707]

at that temperature i think it is ok, but the client has always reason

lm

 

[Ehzin]

While I don't disagree with attempting to inform the client of the possible benefits in performance and availability of an "upgrade" material this shouldn't allow a vendor/EPC/etc... to make that decision to upgrade for them. I hope this doesn't come off as an assumption of your particular scenario I just caution material providers for making decisions to upgrade/change material choices without the express approval of a client. I've just seen vendors make "or equal" decisions without fully informing the client of the change. Like I said, may not represent your scenario but you shouldn't have to fight a battle to convince a client of an upgrade. If they want to pay for harder to source or more costly materials it's their prerogative. They deal with the cost or schedule delay if they decline your recommendation.

Thanks,
Ehzin

And apologies if the above commentary is unsolicited.

 

[mk3223]

IMO, first is to understand where the 316SS material was come form , i.e.:
- Was it listed the Piping Spec?
- Was the substitution proposed by the Vendor? And, who approved it?

If from the Piping Spec, your Material Engineer may provide a written doc for supporting it. If the Vendor proposed it, he may provide a validation for a good fit of the service. So, you may present them to the Client for review and approval, if not done so in the design phase.

Also, you may present a cost estimate for replacing these 316SS gasket with 304SS, with the hours of Labor to replace them, to the Client for consideration.

 

[Murali-1311]

Ehzin,
for me it's a lesson learnt worth risk taken,
I'm trying to figure out what is not letting the client to approve such an upgrade, eager to learn if there are any generally known technical reasons for not approving SS316 instead of SS304 or is it just the Project politics?

mk223,
-SS316 came from the gasket supplier as an alternative which was readily available in place of SS304 which needed 4-5 weeks lead time
-Piping spec mentions SS304 gaskets but the MOC for pipes & fittings are Carbon steel.
-substitution was proposed by gasket supplier, approved by us (the fabricator) hoping we could get it approved by client in parallel since official approval takes some huge time which we couldn't afford due to schedule constraints.

 

[mk3223]

Murail-1311,
As a Fabricator, it could be difficult to convince the Client for the different material after the fact. It can be imaged that no one would like the surprise from the Fabricator due to the material deviation from both the engineering design and Client Spec without a "pre-approval" before fabrication.
And, I don't think that the "long" material lead time was a proper reason for the action, because the unacceptable piping could impact the project completion and turn-over.
Can the Client Engineer help to review it and see if the material is fit for the service?