Specifies the pressure variance.
Typical units (depending on your unit system):
-
lb/in²
-
Bar
-
KPa
-
MPa
The field name changes according to the selected piping code.
ASME and RCC-M C, D
Variance in the pressure between operating and peak to be used as the component in equation 9 above that found from B1 * P * Do / 2tn. Do not type the peak pressure for Pvar. Type the difference between the operating pressure and the peak pressure.
Swedish Power Code, Methods 1 & 2
Beta for the Seff calculation. If not given, this value defaults to 10%. Type ten percent as 10.0. Values must be between 0.1 and 25.0. Values specified outside of this range are automatically adjusted to the outer limit of the allowed range. The definition for beta, as given in the Swedish piping code in section 5.6.2.1, is the "maximum allowable minus the tolerance as a percentage of the nominal wall thickness".
Stoomwezen
Cm coefficient in the code whose value is usually 1.0.
Norwegian
Difference between design pressure P (in equation 10.7) and peak pressure Pmaks (in equation 10.8).
The table that follows defines when each of these parameters is valid input for the piping code (V) or not required (N).
DNV
Usage factor N for equivalent stress check from Table C4. Values must be between 0.77 and 1.00.
PD-8010 Part 1
Design factor as discussed in Section 6.4.1.2. Typical limits on this value are 0.3 and 0.72, depending on categories and class locations. This design factor determines the allowable hoop stress. This value has no units for PD-8010 Part 1.
PD-8010 Part 2
Design factor as discussed in Section 6.4.1 Table 2. Type the value of fd for the hoop stress evaluation. This value should be either 0.6 (riser/land fall) or 0.72 (seabed/tie-in). CAESAR II determines the appropriate fd values for the equivalent stress from Table 2. This value has no units for PD-8010 Part 2.
This value is taken from the Material Database, if available and applicable, unless you type a value.
ISO 14692
Pvar is used in a different way. See the Reference for ISO 14692.