You are here: Home» FAQ» Recommendations for flat gaskets

Recommendations for flat gaskets

Proper installation is essential to ensure that a gasket will function reliably. Sealing surfaces and bolts must be selected based on the minimum required surface pressure and maximum permissible surface pressure for the gasket.
Please note
Only use new, undamaged and dry gaskets; observe storage conditions (see below).
Thoroughly clean sealing joints without scratching them, then dry them.
Place gaskets in the center; do not use any aids (such as grease, releasing agents or sealers) on gaskets or sealing joints.
Do not use corroded bolts, nuts or washers. The calculated and actual surface pressure must correspond to one another, so apply lubricant to the bolts and nuts.
Install second sealing joint plane-parallel and tighten the bolts by hand. In order to achieve an even pressure distribution, apply defined screw tightening in a criss-crossed pattern in at least three stages.

Stage 1: 20 % of the required torque.
Stage 2: 60 % of the required torque.
Stage 3: 100 % of the required torque.

All of the bolts must have the same required torque.
All gaskets will settle, especially after having been installed for long periods of time. Retighten bolts at 100% torque prior to initial commissioning.
Fiber or PTFE-based gaskets which have already undergone high operating temperatures should only be retightened when cold. This should also be done in several stages and great care should be taken, since there is a risk of destroying the gasket (especially with fiber gaskets which have already hardened).

Storage conditions for fiber-based gaskets and gasket plates (FA pursuant to DIN 28091-2)
Maximum shelf life of two to three years under the following conditions:
Temperature < + 20 °C
Relative air humidity 30 % to 60 %
Away from direct sunlight
No artificial light with high UV content
No ozone
Must not be stored under tension

Major deviations from these conditions will shorten the permissible storage time. If critical (i.e. toxic) gases are involved, the storage time may not exceed one year. Store gaskets or gasket plates in special packages (airtight and light-protected) if necessary.