The minimum recommended ceiling height for recreational trampolining is 5 metres . For competitive trampolining a minimum of 8 metres is advisable. This measurement is taken from the top of the trampoline frame to the lowest protruding item on the ceiling that may interfere with someone bouncing on the trampoline.
These measurements are not set in stone. It is up to the head coach or teacher in charge to risk assess the area and decide if the ceiling height is appropriate to the trampolining activity taking place and the pupils being taught.
If you have SEN pupils bouncing on their bums for most of the session, a 5 metre ceiling height is not necessary. If you have primary aged children practicing simple skills they will not require much height. The key is to risk assess. Draw up a written risk assessment to show you have taken steps to protect the pupils and reduce the risks involved during your trampolining sessions. Keep a record and refer to them every session.