adaquate torque at hydrostatic test

[elen_28]

hi,
Our company manufactures shell and tube heat exchanger.

current spec is following:

◎code : ASME sec.VIII div.1-1998(by customer's local regulation)

◎working pressure…shell:0.2MPa /channel:6.3MPa

◎design pressure…channel:7.0Mpa

◎hydrostatic test pressure…channel:11.0Mpa(by customer's local regulation)

◎channel girth flange…ANSl B16.5 304(18Cr-8Ni) 24" class 600 M&F

◎shell girth flange…ANSl B16.5 304(18Cr-8Ni) 24" class 600 SOP RF

◎tubesheet…O.D. is equal to girth flange.
304 SOP M&F/RF t=103(by equation of code)
All bolt holes are threaded for alternative of coller bolt

◎gasket…spiral wound gasket with inner/outer ring

◎bolts and nuts… M48 A193-B7/A194-2H

Our company member is drafting the bolting procedure for this.

current issue:
"Which pressure should be select on calculating torque at channel side hydro static test?"

working…6.3Mpa
design…7.0MPa
hydrostatic test…11.0MPa

various opinions :

1. adaquate torque all time should be calculated by design pressure.

2. adaquate torque is not one.
on working, by design pressure.
on hydrostatic test, by hydrostatic test pressure.

3. torque is calculated by design pressure. adaquate torque is calculated torque×1.5 (safety rate)

1 is design manager's argument.
(He insists that ASME code provides bolting torque equation by design pressure.)

2 is manufacturing manager's argument.
(He insists that real hydro static test pressure is 11MPa and end force of 11MPa should not be neglected, the torque of the test should be calculated by test pressure for safety of construction site staff.)

3 is our major customert's basic procedure.(not current case customer)

In my opinion 3 is adaquate.
Please let me know your opinion.

 

[LittleInch]

Sounds like 2 to me,

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

 

[elen_28]

LittleInch,thanks for your reply.

opinion1 is not safety for hydrostatic test.
I persuade the design section manager
to calculate adaquate torque for hydrostatic test.

 

[XL83NL]

M48 studs/bolts on a B16.5 flange is rather strange.
Have you checked what PCC-1 might recommend on this?

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