Flare System Backpressure Calculator
Evaluates built-up backpressure in flare headers and its effect on pressure relief valve capacity. Ensures compliance with API 521 backpressure limits (10% conventional, 50% balanced, 70% pilot-operated) and calculates the Kb capacity correction factor per API 520.
Pipe Geometry & Flow Parameters
lb/hr
in
ft
count
count
count
count
Fittings use L/D ratios per Crane TP-410
Gas Properties
g/mol
°F
psia
-
Cp/Cv
cP
Typical natural gas: μ = 0.01-0.015 cP at operating conditions
Relief Valve Parameters
psig
lb/hr
Valve Type Limits:
• Conventional: Max 10% backpressure (normal)
• Balanced Bellows: Max 50% backpressure
• Pilot Operated: Max 70% backpressure
📚 Learn the Theory
Learn API 521 backpressure limits, relief valve capacity, and network analysis