It is not possible to specify PROMATECT®-250 for a mezzanine floor where the joists are less than 172mm because of the size of the joists used to complete the test and the fire assessment following the test.

Our solution would be to install a SUPALUX® Suspended Membrane Ceiling attached by hangers to the galvanised steel joists to form a fire rated ceiling, fire from below only. If the ceiling is set at a level below the steel framework, the ceiling will also provide protection to the structural steel sections. See page 123 and 124 of the Fire Protection Handbook for the suspended ceiling system.

Alternatively, the ceiling can be fixed with shorter hangers, so the ceiling level is immediately below the line of the joists and with the steelwork separately protected using PROMATECT®-250 fire protection board.