Regarding working and hydrotest pressure 1

[purode333]

Dear sir,

As we know, As per ASME sec VIII div I, Hydro test pressure = 1.5 x Design pressure.

AS per B 31.3, Hydrotest pressure = 1.3 x Design pressure.

AS per ASME sec VIII div. I, MAWP=Design pressure. (means if working pressure or design pressure, any one of it, given in drawing then, we will get hydro test pressure).

What in terms of B31.3. (if only working pressure given in drawing/specification, then what will be the hydrotest pressure.)


Regards
Prasad Rode

 

[LittleInch]

Where did you get 1.3 x for B 31.3??

Section 345.4 states 1.5 x design pressure.

If you take the stated working pressure as the design pressure, this might limit you in the future. You really should find out the design pressure.

You can test as one system if you can't separate the two, but only if the vessel test pressure is >77% (strange figure) of the piping test pressure.

For piping, unlike pressure vessels, design really is the highest pressure allowed. You can't set or calculate a MAWP or MWP higher than the design pressure in B 31.3.

There are many many posts on this subject if you search for it.

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

 

[XL83NL]

Section 345.4 states 1.5 x design pressure.

Times the stress ratio S_T/S

 

[TomBarsh]

"As we know, As per ASME sec VIII div I, Hydro test pressure = 1.5 x Design pressure."

The factor for a UG-99(b) test has been 1.3 since the A99 Addenda (1998 Edition), when the design margin for allowable stress (based on ultimate) was changed from 4.0 to 3.5. That was 16 or 17 years ago (gosh, that's hard to believe).

And as XL83NL indicates there is the ratio of the allowable stresses at the test and operating temperatures to consider as well.

 

[purode333]

Dear sir,

Sorry for mentioning in my first posted thread that in B31.3, hydro test pressure = 1.3 x desgin pressure.

So. AS per B 31.3, hydrotest pressure = 1.5 x design pressure.

Sir, my question is that, as mentioning in my case on site (Practically, in doing hydrotest, hydrotest pressure not given in drawing.
But only working pressure of pipe line is given).
So, how could we get hydro test pressure from working pressure?.

Sorry for intervention again.

Regards
Prasad

 

[XL83NL]

Again, 1.5 times design pressure times stress ratio?

 

[LittleInch]

Prasad,

Design pressure and test pressure are usually provided either on the isometric, the pipe schedule or pipe spec or the line list. It is very strange that you don't have access to those important documents but you're being asked to define the hydro test.

Of you really can't get those documents then look at the flame rating of the system and the pipe wall thickness to get an idea of the maximum rating, but otherwise use the max working pressure of this is all you have, but you should ask for the other documents

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