Flange gasket design and selection involve several engineering formulas and considerations to ensure proper sealing, pressure containment, and structural integrity. Below is a list of key formulas commonly used in the design and analysis of flange gaskets, particularly in piping and pressure vessel applications. These are based on standards like ASME and general engineering principles.
Minimum Required Bolt Load Formula
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| \( W \;=\; max\; ( W_{m1}, W_{m2} ) \) | ||
| Symbol | English | Metric |
| \( W \) = Minimum Required Bolt Load | \(lbf \;/\; in^2\) | \(Pa\) |
| \( W_{m1} \) = Bolt Load for Operating Condition | \(lbf \;/\; in^2\) | \(Pa\) |
| \( W_{m2} \) = Bolt Load for Gasket Seating | \(lbf \;/\; in^2\) | \(Pa\) |
Bolt Load for Operating Condition Formula |
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\( W_{m1} \;=\; H + H_p \) (Bolt Load for Operating Condition) \( H \;=\; \dfrac{ \pi \cdot G^2 \cdot P }{ 4 }\) (Hydrostatic End Force) \( H_p \;=\; 2 \cdot b \cdot \pi \cdot G \cdot m \cdot P \) (Gasket Sealing Force) |
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| Symbol | English | Metric |
| \( W_{m1} \) = Minimum Required Bolt Load | \(lbf \;/\; in^2\) | \(Pa\) |
| \( H \) = Hydrostatic End Force | \(lbf\) | \(kg\) |
| \( H_p \) = Gasket Pressure Force | \(lbf\) | \(kg\) |
| \( \pi \) = Pi | \(3.141 592 653 ...\) | \(3.141 592 653 ...\) |
| \( G \) = Mean Diameter of Gasket Contact | \(in\) | \(mm\) |
| \( P \) = Internal Pressure | \(in\) | \(mm\) |
| \( b \) = Effective Gasket Width | \(in\) | \(mm\) |
| \( m \) = Gasket Factor (Dimensions from ASME Tables) | ||
Bolt load for gasket seating involves considering factors that ensure a proper seal. Bolt Load is the force exerted by the bolts to compress the gasket. Gasket seating is the initial compression of a gasket to create a leak-tight seal before internal pressure is applied.
Bolt Load for Gasket Seating Formula |
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| \( W_{m2} \;=\; b \cdot \pi \cdot G \cdot y \) | ||
| Symbol | English | Metric |
| \( W_{m2} \) = Minimum Required Bolt Load | \(lbf \;/\; in^2\) | \(Pa\) |
| \( b \) = Effective Gasket Width | \(in\) | \(mm\) |
| \( \pi \) = Pi | \(3.141 592 653 ...\) | \(3.141 592 653 ...\) |
| \( G \) = Mean Diameter of Gasket Contact | \(in\) | \(mm\) |
| \( y \) = Gasket Seating Stress | \(lbf \;/\; in^2\) | \(Pa\) |
