The fully tested and certified arrangements for 60 & 120 minute membrane systems includes the use of non-combustible stone wool type insulation above the line of the Supalux® ceiling lining boards, with a stated minimum density and thickness required for the fire performance element of each. To improve overall thermal performance through the ceiling, additional non-combustible lightweight glass wool insulation can be applied above the line of the rock wool insulation required for the fire performance.

It should be noted that the calculated weight per square metre of insulation for the ceiling will then be above that for the tested system, so you should check to ensure that the maximum flexural strength of the Supalux® boards, at 4.5N/mm², isn't exceeded. In addition to this, each system has a required maximum stress within all hangers, fixings and framing members, of 15N/mm² for the 60 minute system and 10N/mm² for the 120 minute system.