ASME B16.5 #1500 flange maximum test pressure 1

[Delgizjd]

I am currently designing a hydrostatic test article that will utilize class #1500 316 Stainless flanges to connect to the test loop. ASME B16.5 specifies that the maximum working pressure at room temperature is 3600psi, and that the MINIMUM hydrostatic test pressure should be 1.5x the working pressure (5400psi).

What I am trying to figure out is how to find the maximum hydrostatic test pressure I could realistically take the flanges up to before I would start to see leakage at the flange. I know this will be determined by the bolted preload on the flange, but I can’t figure out how to find the maximum force I could put on the flange before I would start warping the pieces or get poor alignment over the gasket joint. If there is a way to find this value, or another code I should be referencing, I would greatly appreciate some assistance.

 

[XL83NL]

Yes. There is. ASME PCC-1 is what you should be looking at. It will have all the answers you’ll need.
Take the free ASME PCC-1 training from hextechnology also, as it’ll help you get up and running asap.

Huub
- You never get what you expect, you only get what you inspect.

 

[GD2]

The OP,
The max hydrostatic test pressure is set equivalent to the yield strength of the material at the test temp. Many Owners would limit this to 90% of the YS to avoid permanent deformation.
Code provides minimum test pressure. Engineers/Owners has to set the max test pressure.

GDD
Canada

 

[LittleInch]

Delgiizjd,

ASME B 16.5 does not state a pressure test for flanges. It states a pressure test for fittings (flanged tees, crosses, Y pieces etc.

your piping design code will specify test pressures.

My guess is probably double the MOP, but you can't define "leakage" and the force on the sealing ring is also very difficult to calculate.

Unless you're talking a blind flange, other forces on the flange will also affect the pressure and sealing force.

Appendix A of B 16.5 might help you in whatever you're trying to do, but as noted, it is not wise to go to yield on bolts or flange materials.



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

 

[jt1234]

Standard flange shall be test to 1.5 x rating pressure at the ambient temperature, nothing to do with MAWP or yield stress, such that it can be qualified as B16.5 standard flange.

 

[Andrew ONeill]

The thing to keep in mind is that pretty much all ASME flanges were designed based on Trial and Error / Testing around 100 years ago give or take, not on calculations. So you are unlikely to find an answer based on calculations*** for the question "At what pressure will it start to leak". There are answers to a slightly different question "what is the max hydrotest pressure the code allows / recommends?" which you will find in the above responses.

***the only underlying concept that might get you close is that the ASME piping standards were / are fundamentally based on a safety factor of "Burst" / 3, but that's talking about catastrophic failure / leakage, not starting to drop. -> probably too far down a rabbit hole for your original question, but is worth noting.

Cheers,

Andrew O'Neill
Specialist Mechanical Engineer
Australia

 

[XL83NL]

***the only underlying concept that might get you close is that the ASME piping standards were / are fundamentally based on a safety factor of "Burst" / 3, but that's talking about catastrophic failure / leakage, not starting to drop. -> probably too far down a rabbit hole for your original question, but is worth noting.

For those interested, the 12 LPS post by BJI in this thread holds an interesting pdf that explains the background of B16.5

Huub
- You never get what you expect, you only get what you inspect.