Standards and regulations
Rockwool 30 minute and 1 hour cavity/fire barriers
Satisfies the requirements of the Building Regulations 1991 (2000 edition). Approved Document B and Appendix A, Table A1, for 30 minutes integrity and 15 minutes insulation.
Rockwool Fire Barriers and Fire Barrier slabs can be used where fire resistant partitions need to be continued above a ceiling into the roof void. They conform with the Building Regulations Approved Document B and fulfill all normal fire insulation requirements for divisions of space.
Composition and manufacture
Rockwool is manufactured from a melt of volcanic rock and limestone. The molten rock is spun into wool, treated with a small quantity of resin and cured to form a mat or slab.
A 25mm galvanised wire mesh is stitched with wire to one face to produce a flexible Fire Barrier with optional aluminium foil faces.
The Fire Barrier slab has a factory applied foil finish to both faces.
Rockwool Fire Barrier will achieve Euro class A1 when tested to the new European Fire Classification.
30 Minute (Half hour) Cavity Barrier - Typical fixing methods
Figures A-B show typical details for Fire Barrier applied to a timber truss construction as a half hour cavity barrier within the roof space to satisfy the requirements of Building Regulation B3 . ((4).
If the truss is constructed from a minimum timber size of 35 to 49mm thick, both sides of all truss members/bracing require protection from fire in order to minimise charring. Figure B shows strips of 50mm Fire Barrier used on the reverse side of the truss for this purpose. Alternatively, a second layer of Fire Barrier may be applied to provide 1 hour fire rating.
Nail plate fixings may fail prematurely in fire unless protected.
The new Rockwool fixing system incorporates an angle support and clamping plate.
For fixing to timber, the Rockwool clamping plate is used compressing the barrier to the timber fixed at 450mm centres.
For fixing to concrete soffits, the pre-punched angle support is fixed using Hilti DBZ or Ejot ECL 35 hammer set anchors at max. 750mm centres.
For fixing to steel purlins, use Hilti SMD 02Z (5.5 x 70mm)self-tapping screws at max. 450mm centres.
To use the patented Rockwool angle support system, bend tongues out to 90 Deg and impale barrier onto them. The slotted clamping plate is then fitted by pushing the tongues through the slots and these are then bent over the face of the clamping plate completing the process.