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 |
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| \(\large{ p = \frac{ 2\;S\; \left( t \;-\; c \right) }{ OD \;-\; 2\;y\; \left( t \;-\; c \right) } }\) | ||
| Symbol | English | Metric |
| \(\large{ p }\) = pressure rating | \(\large{\frac{lbf}{in^2}}\) | \(\large{Pa}\) |
| \(\large{ S }\) = allowable stress | \(\large{\frac{lbf}{in^2}}\) | \(\large{Pa}\) |
| \(\large{ t }\) = wall thickness of pipe | \(\large{ft^2}\) | \(\large{m^2}\) |
| \(\large{ c }\) = allowable corrosion | \(\large{in}\) | \(\large{mm}\) |
| \(\large{ OD }\) = outside diameter of pipe | \(\large{in}\) | \(\large{mm}\) |
| \(\large{ y }\) = ASME B31.1, Table 104.1.2 (0.4 if temperature is less than 900°F) | \(\large{F}\) | \(\large{C}\) |
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 |
values of y | ||||||||
|---|---|---|---|---|---|---|---|---|
| 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 |
Tags: ASME Standards