How do I choose a gasket for a flange?
Work from fluid, temperature, pressure, facing and bolt load. Then compare sheet, spiral wound, kammprofile and RTJ.
Pick a gasket by working through the service conditions first, then the flange it sits in. Price comes last.
Questions to answer
- Fluid. Is it chemically compatible with the gasket material?
- Temperature. Including start-up, upsets and steam-out.
- Pressure. Normal, test and relief pressures.
- Facing. Raised face, flat face or ring groove.
- Bolt load available. Weak or few bolts may not crush a hard gasket.
Common choices
- Soft sheet such as compressed fibre, PTFE or rubber. Low to moderate duty, flat faces, water and utilities.
- Spiral wound with metal windings and a filler. A workhorse for raised-face process lines. Inner and outer rings help centre and protect it.
- Kammprofile with a grooved metal core and soft facing. Good recovery, tolerant of uneven loading.
- Ring-type joint. Solid metal rings for RTJ grooves in high-pressure service.
When in doubt, ask the gasket supplier with full service data in hand. Then tighten it properly.