Design tighter seals with accurate stress. Enter bolt load and gasket sizes in any units. Get seating pressure, required load, and exports instantly here.
The calculator evaluates gasket seating stress using the basic definition of pressure on the gasket contact area:
Two common ways to compute area are included:
| Case | Geometry | Inputs | Output |
|---|---|---|---|
| 1 | OD=150 mm, ID=120 mm | W=120 kN, bolts=8 | q ≈ 31.1 MPa |
| 2 | G=135 mm, b=7.5 mm | Target q=35 MPa | W ≈ 111 kN |
| 3 | OD=100 mm, ID=80 mm | W=60 kN, target q=25 MPa | Required area ≈ 0.0024 m² |
Example values are illustrative only. Use gasket manufacturer data and applicable codes for design decisions.
Gasket seating stress is the compressive stress applied during assembly. It promotes surface conformity and closes micro-leak paths before pressure and temperature cycles begin. Too little stress can leave voids and reduce tightness, while too much can crush softer materials and reduce recovery.
The tool uses q = W/A, where W is total bolt load and A is gasket contact area. Inputs are converted to SI units internally, then reported in MPa, kPa, psi, or Pa. This supports mixed-unit entry without manual conversions.
Two area models are provided. The diameter model uses A = (π/4)(OD² − ID²) for a sealing band defined by inner and outer contact edges. The alternative uses A = π·G·b when an effective width is known from drawings, facing details, or test-based assumptions.
Common flange gaskets span roughly 50–1000 mm in diameter, with assembly bolt loads ranging from 10–1000 kN depending on size and duty. Seating stress is often discussed in the 5–100 MPa range, but limits vary widely by material and construction. For quick context, 1 MPa equals about 145 psi and 1000 kPa in practice.
In the OD/ID model, area scales with the square of diameter, so small geometry changes can shift stress noticeably. Increasing OD or decreasing ID increases area and lowers computed stress for a fixed load. Ensure the diameters represent the actual contact region, not unrelated flange features.
When bolt count is provided, the calculator reports per-bolt load as W/n. This is useful for checking whether an assumed total load is plausible for the fastener size, grade, and installation method, especially when comparing to torque-based estimates.
Optional check values can flag outcomes that deserve review. A low stress may indicate insufficient seating and potential leakage. A high stress may indicate crush risk or excessive embedment. Use checks as prompts, then confirm with manufacturer data and your design basis.
Exporting results improves traceability. CSV supports calculations in spreadsheets and design logs, while PDF is convenient for work packs and approvals. Record the geometry method, units, and computed area so others can reproduce the same seating stress and validate assumptions.
It is the compressive stress applied to a gasket during assembly. It is computed as total bolt load divided by the gasket contact area, and it supports initial sealing before service loads act.
Use OD/ID when you know the inner and outer contact edges of the sealing band. Use mean diameter and effective width when drawings or test data provide an effective width for the gasket.
The physics does not change, but rounding and input interpretation can. Enter the same physical value in the correct unit, and the calculator converts internally to keep the result consistent.
Yes for calculation, but allowable seating stress depends on material. Always compare your computed stress to gasket manufacturer recommendations and any relevant piping or pressure equipment rules.
It is the portion of the gasket that actually carries compressive contact and contributes to sealing. It may be less than the physical width due to flange grooves, facing, or contact mechanics.
Choose “Required bolt load,” enter the target seating stress and gasket geometry, and the calculator returns the total bolt load needed. Add bolt count to see the per-bolt share.
No. Seating stress is an assembly condition. Operating stress depends on internal pressure, thermal effects, and flange flexibility. Use additional analysis for operating conditions and leak-tightness verification.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.