All these criteria are measured against the number of minutes a tests runs before they exceed the failure criteria. The number of minutes is then rounded down to the nearest segment of minutes for FRL’s that are set out by the building code. This could be anything from 15 to 240 minutes. As an example, a loadbearing wall system that achieves 126 mins of structural adequacy, 126 mins of integrity and 119 mins of insulation would achieve an FRL of 120/120/90. So even though it was only 1 minute short of 120 minutes of insulation the rating achieved is only classified as 90 minutes for the purposes of an FRL.
The FRL needed for a particular element is set out by the NCC. The class and type of construction and the type of building element is used to determine what FRL is required. As an example, a wall between apartments in a 4-storey apartment building will require an FRL of 90/90/90 if it is loadbearing or -/60/60 if it is not.
This FRL of the element will also determine the FRL required for any service penetrations in that element. In this example the service penetrations would be required to achieve either -/90/90 or -/60/60 as the structural adequacy is not required for penetration seals.
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