Maximum Pressure for Testing

I don't know exact numbers or formulas, but it looks as though max P_test corresponds to about 2.5 x F_y. This seems reasonable, but is the first time I've seen such a criterion.

The jurisdiction where that applies is as unknown as the OP's jurisdiction.

(Nothing like a citationless "citation".)

Thanks Tornado & Dolby,

Tornado,can you specify Fy meaning

Dolby,I think Ptest= 1.5 x Pdesign x St/S also min test of this document, i already follow this formula but result is different Max P test. You can see this document,sometime Ptest min= Ptest max,but sometime different

F_y is the yield strength of the material in question.

Following links will give some idea about Max. hydrostatic test pressure calculation.

http://www.pipingstudy.com/difference-asme-b311-and-b313.html

Click here

http://www.wmhuittco.com/images/CE_Article_1b.pdf

http://66.18.210.80/manuals/B313%20Process%20Piping%20Course%20-%2019%20Whats%20Different%20in%20B31.1.pdf

http://www.ogj.com/articles/print/volume-98/issue-31/transportation/hydrostatic-testing-1-pressure-ratios-key-to-effectiveness-in-line-inspection-complements.html

this picture may be looked better

MAXIMUM PRESSURE FOR TESTING, CALCULATED IN FUNCTION OF THE YIELD STRENGTH.
P=2St/D

P= Pressure Test S= Minimun Yield strenghth (Porcentage) t= Nominal thicnkness D=Outside Diameter.

Hi,

As per ASME B 31.3 the hydro testing pressure is normally calculated by the formula

HPress = 1.5X Design PresureX (Allowable stress values at deisgn temperature/Allowable stress values at test temperature)

Assuming the design temperature is 120 Deg C and taking the testing medium as water with the temperature as 34 Deg C to 38Deg Celsius, find out the stress values from the tables for your particular material.

If you calculate you should normally get the actual test pressure.

Hope this will clarifies.

Thanks

Kumaran

Hi Whitephone

i already use P=(2xTxSy)/D,but i don't think it right because with my example (2inch SCH XS,D=2.375,T=0.218,Sy=20 ksi,Ptest=3671.6 psi=258 kg/cm2) but following this document you can see at picture ,Pmax=24.8 kg/cm2.

This formula corresponds to the manufacture of pipe (API 5L Secction 10, edition 2007). It's the only one that I know where using a percentage of S is mandatory ( 60% or 75%). Take only like a reference. May be the system to be tested has differences in height of, around, 30 meters? . Among the highest point and the lowest point we apply a variation of 10% of the pressure calculated according to ASME B31.3. This value is used in practice and I do not remember any code that references this. It's just practice and many times owner specifications. For pipeline Hydrotest API 1104, is a little different.

WP

You could save a lot of waiting by ringing your insurance company and talking to them, Boss. After all, if it goes bang it's their problem, so they should know, surely?