Intumescent Fire Mortar
An asbestos-free dry mix to which water is added and then mixed like plaster. No shuttering
boards are required. When set, the mortar is load bearing. It can be drilled with wood bits
and is easily cut to allow the installation of services. Standard single-bag FM mix available in
25kg bags (FM25). A new two-bag FM/A mix comprises one FM25 bag and one 6.25kg bag
of pumice aggregate additive to be mixed uniformly together before adding water – this has
greater volume than the standard FM25 bag yet retains structural integrity.
U S E
Good for fire stopping around building services that pass through floors. Lay rockwool slabs
into the opening, leaving the required depth for the mortar, according to the loading required.
It is essential to fit Envirograf® Product 7 (intumescent wraps) around PVC pipes, cables, or
steel pipes. For areas over 600x900mm, it is essential to reinforce with 30mm chicken wire
mesh, fixed with FB/C straps and support battens. See data sheet for full details.
P E R F O R M A N C E
Tested in accordance with BS476 Part 22 (1987). The test report shows that there was no
loss of integrity of the slab itself during the 240 minutes period and 240 minutes insulation.
For non-load-bearing areas, 25mm thickness will give 240 minutes integrity. For load-bearing
areas, 50mm thickness for light loading, 60mm thickness for medium loading and 70mm
thickness or more for heavy loading.