Can flange gaskets or bolts be reused?
Gaskets should be treated as single use. Bolts may go back in after inspection if your site rules allow it.
Gaskets: treat them as single use. Bolts: sometimes, after inspection, if your site rules allow it.
Why gaskets are one-shot
A gasket seals by deforming into the flange surface. Once compressed and heated, it has taken a set. It will not spring back to fill the same gaps again. A reused gasket is a common reason a joint that sealed for years leaks straight after maintenance.
When bolts can go back in
- Threads clean and undamaged, with nuts that run freely by hand
- No stretching, necking or corrosion pitting
- Same grade and length as specified for the joint
- Not from high-temperature or critical service where your rules call for new bolting
If a stud has been tightened past its yield point, it is longer and weaker than it looks. When in doubt, replace it. Studs and nuts are cheap next to a leak.
Faces
Inspect flange faces each time. Radial scratches across the sealing area give fluid a direct path out.
See the full bolt-up checklist.