Pipe Pressure per ASME B31.1 (104.1.2)

The pressure rating of comparable pipe material to fitting material.

 

Pipe Pressure per ASME B31.1 (104.1.2) formula

\(\large{ p = \frac { 2\;S\; \left( t \;-\; c \right) }     { OD \;-\; 2\;y\; \left( t \;-\; c \right) } }\)

Where:

\(\large{ p }\) = pressure rating

\(\large{ c }\) = allowable corrosion

\(\large{ S }\) = allowable stress

\(\large{ y }\) = ASME B31.1, Table 104.1.2 (0.4 if temperature is less than 900°F)

\(\large{ OD }\) = outside diameter of pipe

\(\large{ t }\) = wall thickness of pipe

 

values of y

Temperature °F	900 and Below	950	1000	1050	1100	1150	1200	1250 and Above
Ferritic Steels	0.4	0.5	0.7	0.7	0.7	0.7	0.7	0.7
Austenitic Steels	0.4	0.4	0.4	0.4	0.5	0.7	0.7	0.7
Nickel Alloys UNS Nos. N08800, N08810, N08825	0.4	0.4	0.4	0.4	0.4	0.4	0.5	0.7

 

Temperature °C	482 and Below	510	538	566	593	621	649	677 and Above
Ferritic Steels	0.4	0.5	0.7	0.7	0.7	0.7	0.7	0.7
Austenitic Steels	0.4	0.4	0.4	0.4	0.5	0.7	0.7	0.7
Nickel Alloys UNS Nos. N08800, N08810, N08825	0.4	0.4	0.4	0.4	0.4	0.4	0.5	0.7