What RTJ flange gaskets to buy for pressure class 2500 valve 1

[ballvalve1337]

Hello,

i wonder why a lot of CL2500 valves have ASME B16.5 RTJ flanges to seal with RTJ gaskets according ASME B16.20.
Correct me if i am wrong but for what i have just read the R or RX type according ASME B16.20 are only applicaple up to 5.000 psi
which is below the max. CL2500 Rating of around 6000-6200 psi.

The Problem:
I want to connect a stainless steel Valve (F347H), CLASS 2500 with ASME B16.5 RTJ connection flange to our test bench.
Pressure up to 6200 psi at ambient temp and 4200 psi at 842°F.
What Kind of RTJ gasket to i have to buy?

Thanks for any advice

 

[gerhardl]

A supplier of 'custom made' gaskets familiar with the local regulatioans will give you the best advice. This will obviously not only be based on the strict regulations to be followed, but also give advice on material type/combinations, exact geometrical form and measures, and best material based on fluid and other process details.

A customized sealing does not necessarily cost more than a standard, and a good supplier will in most cases be able to offer both.

 

[jmec87]

Correct me if i am wrong but for what i have just read the R or RX type according ASME B16.20 are only applicaple up to 5.000 psi

Where did you read this?

Standard R/RX gaskets are commonly used for pressures above 5000 psi.

 

[ballvalve1337]

@jmec87.
Different Kind of RTJ supplier literature. It is a bit confusing since 1.5x CWP at Shell testing is around 9300 psi.
I will look for an example link later...

 

[ballvalve1337]

https://flexitallic.com/us/wp-conte...esign-Criteria-Brochure_5-15-2019-low-res.pdf

page 38. Ok here it is 6250psi max acc. ASME and 5000psi acc. API for Style R and RX.
But still not applicaple for pressure test @ 1,5xCWP

 

[jmec87]

Thanks for providing that source. Note that it is describing the history of a traditional design; it is not specifying usage limits like a customer spec or standard would.

Style R ring type joints are designed to seal pressure up to 6,250 psi in accordance with ASME B16.5 pressure ratings and up to 5,000 psi in accordance with API 6A pressure ratings.

These design pressure ratings are working pressure ratings, not test pressures. Standard R-type gaskets are very commonly used to test to 1.5x the above-mentioned design pressures.

Rubber coated ring gaskets (shown on page 40 of your source) are also used for testing sometimes. They have the advantage of being reusable (reuse of normal R-type gaskets is not recommended, although may sometimes be possible) and minimizing damage to the ring groove surfaces.

 

[ballvalve1337]

This makes sense!
We will use R-type for testing now. Stainless steel 316 with restricted hardness to avoid damaging the ring grooves of the Stainless steel Valve.