About 100 Minutes Under Floor Fire Barrier
The barrier consists of graphite-impregnated cloth, covered with a reinforced Kraft paper and sealed.
The graphite-impregnated side faces downwards and outwards on the sides folded up the joists and this expands in a fire, sealing any void between the barrier and the joists.
Metal fixing plates 30mm x 50mm with a hole drilled in the middle are used to fasten the barrier to the joists with 30mm galvanised clout nails (nails not supplied).
When ordering under-floor fire barrier, the width measurement required is the width between the joists plus 100mm, as there must be a 50mm fold of the barrier fitted to the joist on each side.
For example, if width between joists was 400mm, then you would need to order a barrier with 500mm width.