PRESSURE VESSEL HYDRO TEST

[hdpinsp]

What would be the hydro-test pressure for a vessel with MAWP 311 psi, rolled from SA516-70N, with .875" nominal thickness? And how is this calculated. Max temp. is 230F and Min is -20F

 

[rumandcola]

What design code are you using?

 

[Turbo777]

What's the design pressure?

 

[Turbo777]

According to ASME code Sec.VIII div.1, (UG-99)it should be MAWP x 1.3 x LSR.
311 PSI x 1.3 x 1.064 = 430 PSI.

 

[jte]

As rumandcola points out, this question is unanswerable without knowing the code of construction.

Further, the edition of the code can play a role as well. If this particular vessel was fabricated in 1995 to VIII-1, then Turbo777's response is incorrect.

But... It could be a Section I vessel, it could be Section III (ok, I kind of doubt that), could be Section XII, could be Section VIII Div. 3 (ok, I kind of doubt that as well).

Or... it could be AS 1210, GOST, PED...

We just don't know given the info provided.

jt

 

[hdpinsp]

My apologies, the code in use is ASME Sec. VIII Div 1, how do you determine LSR?

 

[weldstan]

With a design temp < 650 F it's 1.3 x the design pressure per ASME VIII, Div.1. Above that temp, increased pressure is required. ASME VIII, Div.1 provides the formula.

 

[marty007]

hdpinsp,

LSR is essentially a factor that takes into consideration how much stronger the material is during a hydrotest compared to at its design temperature.

You have to go through each component in the vessel and divide the allowable stress at your test temperature by the ASME allowable stress at design temperature (230°F). The LSR is your lowest ratio calculated for all components.

As weldstan points out, SA-516-70 maintains its full strength for quite a while (it's actually at full strength only up to 500°F in ASME 2013), so the LSR is 1.

Cheers,

 

[jte]

hdinsp-

You may need a 1.5 multiplier, rather than 1.3. It depends on the edition (year) of VIII-1 to which a particular vessel was built.

When verifying LSR, don't forget to also check other components - you likely have a bit of SA-106, SA-105, etc. These may govern.

jt

 

[GenB]

Jte. Pls all are talking about new construction and at this time it can only be 2010 edition or the latest 2013 edition. Inservice vessels are not ASME concern.

 

[jte]

GenB- On what basis do you make the claim that this question relates to new construction? The replies from Turbo777 and marty007 relate to new construction.

The original post does not state new or in-service (despite requests for clarification) - and as I'm sure you'll agree, no AI or fab shop guy would ask this question. Thus, the very real possiblitiy exists that this is relating to a repair or alteration of a vessel in the field. Rumandcola does not assume "new", and weldstan mixes new and old.

weldstan- As marty007 points out, you are mixing pre- and post-1999 info. You don't get SA516-70 with constant stress up to 650°F and a basic stress multiplier of 1.3.

jt