Upgading a ball valve

[Johnrem]

Hi Every specialist:

I have an API 6D ball valve that shall sustain 450 bar @ 70°C. This presseure is over CL2500. Gas service, none corrosive.

Client specification stipulated that it shall be an uprated valve.

Can someone explain me what shall be an uprated valve? Is uprating done based on additional and special tests or based on on additional wall thickness on the valve body?

 

[Johnrem]

Me again;

I just want to add these informations:
Service: Gas injection
Valve body material: A350 Gr LF2 for valves near wellhead and A216 WCB far from welhead.
Valve ends: Hub ended type

Many thanks

 

[rneill]

I'm not sure what your client means by uprated but I have two options for you:

1. Buy an API Class 10,000 valves that will have the required pressure rating.

2. Buy an ASME Class 4500 weld end valve and then attach the hubs (good for 765 bar).

With regards to your materials, A350 is a low temperature material, A216 is not. I would think that the difference would not be proximity to the wellhead but rather whether the valve was exposed to cold ambient temperatures or not?

 

[Johnrem]

Rneil;

1) Client refused to buy API 10000 valves. For ASME CL4500, accepted Vendors by clients said to me that they are not "certified" or " authorized" to manufacture this special class (it seems that they need to be certified to do).

2) A350 material is selected because when flaring the metal temperature reachs vey low temperature at the vicinity of the PSV.

3) Can you explain what derating an API10000 valve to 450 bars (6525 psi)working pressure means?
I mean: the final dimensions of this derated valve (wall thickness and end dimensions) will be those of an API 10000 valve or will be special dimensions for 450 Bars?

Regards

 

[gerhardl]

Without commenting directly on a possible choice, this seems to me the classical case where an end user/client tries to avoid a correct technical classed (allowed and certified product) and seeks a lower priced product that either is non-existent or commercially not available at the price wanted and / or not allowed under the given technical conditions.

If this is the case, there is only one way out: present cost and technical consequences in clear text for the customer (in writing), and ask for his decision on the matter.

On the other hand, the description might be (as it often is) an adaption or from an older plant or description, but where 'something' is slightly changed.

Antway, if the answer insists on 'cutting corners' and allow 'non allowable products' I would definitely not say yes for myself and my company.

Good luck with your product search!

 

[rneill]

I know of know official procedure to design and built an intermediate class valve to API 6A, you are either API 5000 or you go up to the next class, Class 10,000.

If you need more rating than you can get from API 5000 then I would specify API 10,000.

If the client doesn't like that answer, and has an alternative proposed solution that doesn't seem to be covered by the established standards, tell them to put a Professional Engineers stamp on the design and then you'll be happy to proceed with it but that you are can not take responsibility for the design as you have no basis on which to validate it's acceptability.