Depressuring System Calculator
Calculates required depressuring rates and flare system capacity for emergency blowdown scenarios. Follows API RP 521 methodology for safe pressure relief and fire exposure protection.
Calculation Mode:
Vessel & Pressure Parameters
ft³
psig
psig
°F
in
ft²
API RP 521: Depressurize to 50% of design or 100 psig, whichever is lower
Fire Case & Material Properties
BTU/hr
Pool fire: Q = 21,000 × A^0.82 BTU/hr (A = wetted area in ft²)
°F
0-1
F = 1.0 (bare), 0.3 (fireproofed), 0.075 (2" insulation)
min
Gas Properties & Valve Parameters
in²
-
Air=1
-
Cp/Cv
BTU/lb-°F
lb/ft³
°F
%
BTU/hr-ft²-°F
Typical: 5-10 BTU/hr-ft²-°F for gas flow
Design Results
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About This Calculator
Emergency depressurizing system design per API RP 521 for fire case scenarios.
Key Requirements:
Time: Depressure to 50% design or 100 psig within 15 min
Wall Temp: Keep within material limits during fire