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Rupture Disc Sizing Calculator

API 520 Part I + ASME VIII UG-127

Size a rupture disc for gas, liquid, or steam service per API 520 + UG-127. Three service modes; supports standalone disc and disc + PSV combinations (K_c = 0.9). NPS recommendation based on commercial disc sizes.

Service & Flow

lb/hr
psig
psig
°F

Fluid Properties

lb/lbmol

Disc & Coefficients

Method

Gas (critical):

A = W / (C · Kd · Kc · P1 · √(M/(T·Z)))

Liquid (API 520 Part I):

A = Q · √(G / ΔP) / (38 · Kd · Kc)   (Q in gpm, G = sp. gr.)

Steam:

A = W / (51.5 · Kd · Kc · P1)