Ensure that the Bellows Expansion Joints are not imposed with higher thermal movements than the specified value.

The higher magnitude of movement than the specified design movement during operation will cause higher bending stresses in the Bellows resulting in pre-mature failure.

Evaluate thoroughly for realistic thermal movement of piping and movement of connected equipments etc.

Adding arbitrary safety factors will also result in highly flexible joint compromising the stability or result in un-economical design.