P.N Rating For Valves

14 kg/cm² ≈ 198 psi (lb/in²). From this I would guess that any PN rating of 200 or greater would be satisfactory. This is only a guess, because I don't work within the PN designation system.

Refer to din standards.

Generally, it should be only PN 10

Sir,

Thankyou for your reply.Also i would like to know if Cast Iron to IS 210Gr FG220 would be suitable for valve having cold working pressure of 14kg/cm2.

Thanks & Regards

Pareen Shah

Hi Shah,

PN 10,according to DIN standards is covering the mentioned condition.This is equivalent to ASME pressure rating of class 150.

Sayed Sarhan

If I am correct, at room temperature, permitted working pressure according to ASME class 150 is 19 bar. This is much more than working pressure of 14 Kg/cm^2 of original post

Hi gsuhas,

ASME Class 150 is covering a range of pressures and temperatures,if you refer to ASME/ANSI B16.34-1988,ratings for group 1.1 materials(A105 and others),table 2-1.1A,standard class,you will find that working pressure of class 150 is covering the following range:

working pressure 285 psig at -20 to 100 deg F and up to 20 psig at 1000 deg F.

The subject pressure (assuming it is at room temperature)is laying within this range.

Sayed Sarhan

• The attached figure demonstrates the DN & PN and Class of flange (Link:
ASME_Flanges_Class_PN & NPS ).

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•To find the Class (Rating) or PN of a flange, valve, or flanged connection, you have to define a 3 parameters:

- Design Pressure

- Design Temperature

- Material

• Then go to ASME B16.5 for NPS 1/2 up to NPS 24 (DN 15 up to DN 600) or ASME B16.47 for NPS 26 up to NPS 60 (DN 650 up to DN 1500).

pressure rating for 14kg/cm2 is 150class, because for 150 class, seat test pressure is 22kg/cm2.