Flange Bolt Load Calculator

ASME PCC-1 bolt load: gasket seating, hydrostatic end force, operating bolt load, target torque.

Flange Size (in NPS)

Pressure Class

Bolt Diameter (in)

Number of Bolts

Bolt Root Area (in²)

Design Pressure (psig)

Gasket OD (in)

Gasket ID (in)

Gasket Factor (m)

Gasket Seating Stress (y, psi)

Nut Factor (K)

Gasket Seating (Wm2)

lbf

Hydrostatic End

lbf

Operating Load (Wm1)

lbf

Per-Bolt Load

lbf

Target Torque

ft-lbf

Method (ASME PCC-1 / ASME VIII)

Wm2 = pi × b × G × y — Gasket seating load (bolt-up condition). b = effective gasket width, G = gasket reaction diameter.

H = pi/4 × G² × P — Hydrostatic end force from internal pressure.

Wm1 = H + Hp where Hp = 2 × pi × G × b × m × P — Operating bolt load.

Torque = K × D × F — Short-form torque equation per ASME PCC-1. K = nut factor (0.20 typical for steel on steel, lubricated).

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