rating vs. maximum testing pressure 2

[aironyx]

which relation there's between valves and flanges rating (# 150, 300, 600, 900, 1500.......) and maximum testing pressure?

 

[SnTMan]

aironyx, at least for flanges, hydro test pressure, is 1.5* the ambient temperature pressure rating which IS NOT 150, 300, 600, etc., but rather the values in the rating tables. Rounding can also be involved.

Can't say about valves, but it would not surprise me if the same basis was used.

Regards,

Mike

 

[786392]

Dear aironyx,
I generally observed the normal practice (No Code reference recalled right now!)
Hydro test pressure=1.5 X operating pressure
However practically it is most usually considered as
Hydro test pressure=1.5 X rated pressure
(i.e. 150#,300#.. and so on)
Whereas Brand new fabrications are seen to be
Hydro tested=2X rated pressure*(i.e 150#, 300#... and so on)
*Conditional to the stress bearing capabilities.
Some Learned forum members will just correct/put the relevance intact soon.


Best Regards
Qalander(Chem)

 

[JLSeagull]

By testing, are you refering to piping system hydrostatic testing? Perhaps you are not addressing tanks, vessels, flow meters or pumps as you mention valves. What codes and standards apply?

Perhaps temperature matters for some applications.

Many different codes and standards exist and may apply depending upon the type process etc. Is this for wastewater, a refinery, a power boiler, cross-country pipeline, domestic USA or some international application? This involves the selection of ASME B31.1, B31.2, B31.3, B31.4 or B31.8. What is the fluid? If chlorine or other toxic or incompatible fluid then hydrostatic testing may not be permitted. Boiler external piping
is hydrostatically tested in accordance with PG-99 of Section I of the ASME Boiler and Pressure Vessel Code. The test shall be conducted in the presence of the Authorized Inspector. The requirements may differ depending upon the wall thickness.

Let's assume that you are not interested in gray iron flanges. ASME B16.5 covers smaller flanges, B16.47 covers really large flanges. ASME B16.34 applies to valves. API STD 598 applies to valve testing when specified.

ISA 75.19.01 applies to control valve hydrostatic testing.

Subsea valves may require external hydrostatic tests.

B16.5 - Flanged joints and flanged fittings may be subjected
to system hydrostatic tests at a pressure of 1.5 times the
38°C (100°F) rating rounded off to the next higher 1 bar
(25 psi) increment. Testing at any higher pressure is
the responsibility of the user, taking into account the
requirements of the applicable code or regulation.

 

[metengr]

For valves, ASME 16.34 applies. See Section 7

(a) 7.1 Each valve shall be given a shell test at a gage pressure no less than 1.5* the 100 deg F rating rounded off to the nearest next higher 25 psi increment. Test times are also given based on diameter of the valve bore.