Flare System Backpressure Calculator
Evaluates backpressure in flare headers and its impact on relief valve performance. Ensures compliance with allowable backpressure limits for conventional and balanced relief devices per API 521.
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
Backpressure Results
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About This Calculator
Analyzes pressure drop in flare headers and impact on relief valve capacity per API RP 520/521.
Key Aspects:
Pressure Drop: Darcy-Weisbach equation with fittings