RCM FR PRO Silicone Sealant is a one-part silicone sealant formulated to provide a high degree of fire resistance in a variety of joint configurations. It has been independently tested and achieves in certain joint configurations an integrity and insulation value of more than 4 hours.
It exhibits excellent unprimed adhesion to most building components and is suitable for sealing a wide range of construction and expansion joints in buildings, where compartmentalisation within the building is required to control the spread of fire. It crosslinks at room temperature to give a flexible low modulus seal that will withstand movement of 25% in constant service throughout a wide temperature range.
It exhibits excellent primerless adhesion to a wide range of substrates such as Glass, Anodised and Mill Finished Aluminium, Steel, St.Steel, rigid PVC, Concrete and other porous surfaces.
Once cured, the sealant offers superb long-term resistance to heat and fire as well as all other general weather elements.
EN 1366-4 - 4 Hours Integrity + Insulation
Usage depends on the fire rating of the wall:
For use on Fire-rated walls:
Where a sheathing board is specified within a fire-resistant external wall to one of the fire tests standards, BSEN1364-1:2015, BSEN1365-1:2012, BS476-21:1987, BS476-22:1987. The board should be installed as per the applicable fire test and guidance from the RCM technical team.
RCM sheathing boards: Y-wall, Multipurpose, Cemboard are typically tested either with lightly butted joints or with a 2-5mm board gap filled with an RCM FR PRO / NULLIFIRE-FS703 fire seal mastic filling the joints.
On-site to allow for expansion and contraction, RCM Y-wall, Multipurpose boards should be installed as per RCM fixing guidance. However, there is a very small risk during construction in highly exposed locations or where boards have been exposed to excessive moisture for prolonged periods minor expansion of board may occur. In this situation, our recommendation would be for a gap of 2-5mm to be left between the boards and an RCM FR PRO / NULLIFIRE-FS703 seal fire mastic used within the joints.
RCM DensGlass boards are fitted by butting boards together and sealed with a bead of RCM FR PRO fire seal mastic to all mating edges.
RCM Cemboard can be susceptible to minor swelling if left exposed for any protracted period. We recommend that a gap of 2-5mm be left between the boards and subsequently fill all joints with RCM FR PRO / NULLIFIRE-FS703 fire seal mastic.
For use on Non-fire rated walls.
RCM Y-wall, Multipurpose can all be butt jointed for limited exposure periods that are not subjected to excessive moisture penetration. As a precaution where excessive moisture penetration situations arise, our guidance has typically been to leave a small gap of between 2-5mm. DensGlass boards are installed with butt joints.
Concerning RCM Cemboard, as these boards is may demonstrate very minor swelling if left exposed for any protracted period, then our recommendation for this product is to always leave a small gap of between 2-5mm between the boards and fill or tape joints as per the project recommendation.
Where air leakage is a consideration all RCM sheathing boards joints should be taped with RCM tapes or filled with RCM FR PRO / NULLIFIRE-FS703 mastic.
We recommend that all products are taped to seal against weather infiltration to the underlying building fabric and construction and the board edges, this is particularly pertinent with RCM Cemboard to prevent moisture entering the sub composition and causing excessive swelling.