Gandhi Automations’ deconstructs the essentials of fire shutters.
A traditional single skin fire resisting rolling shutter looks and operates in a similar way to a standard steel rolling shutter. The physical differences are that the materials used, are heavier and there are more fixings required.
Fire shutter structural recommendations
The structure supporting the rolling shutter must be fire resistant (to BS476, Part 20, 21, 22, 1987), having a resistance equal or greater than that required of the rolling shutter itself and must be capable of supporting the shutter for the required period without compromising the performance of the rolling shutter.
Fixing to masonry openings
The opening has to be constructed from masonry, reinforced concrete or dense concrete blocks and should have a fire resistance equal or greater to that of the door.
All concrete or masonry elements must be designed in accordance with BS5628: Part 3:1985 and have a density of >600kg/m³. Lintels spanning the structural opening should comply with BS8810:
Client should ensure that the openings are plumb, square and that the structure will accept raw bolt type fixings without cracking.
Subject to the fire shutter being fitted to a flat surface, gaps of up to 6mm are acceptable (for a distance of 150mm), but if, due to an uneven structural finish, larger gaps are apparent, they must be sealed with a suitable fire retardant material.
Fixing to steel openings
When fire resistant rolling shutters are fitted to steel openings, the steel must be insulated and thermal bridging effects should be considered where insulation has been breached.
It is recommended that a critical steel temperature of 400°C and steel sections with an Hp/A below 230m-1 are used for designing fire resisting steel supporting structures.
Fixing to timber partitions
Fire resisting rolling shutters can be fixed to non-load bearing timber frames or steel framed partitions, that are up to 2,750 mm wide and 3,250 mm high, (maximum area 10m²), for up to 60 minutes under cover of the BRE test certificate FG 7941 N. The opening must be capable of carrying the weight of the shutter and be equal or greater than the fire resistance of the rolling shutter assembly.
It is most important that the contractor adheres to the opening construction details, as these are also covered by the assessment and as such become the contractor’s responsibility.
Please note that it is a requirement under the Regulatory Reform (Fire Safety) Order 2005, that fire resisting rolling shutters are tested every six months. Access should therefore be allowed to the mechanism to enable this to be carried out. Gandhi Automations can offer routine testing and maintenance contracts on application. If no contract is signed, we cannot take any responsibility for the working condition of the shutters after the guarantee period.
Fire shutters over fire exits and escape routes
As required, under Appendix B of the Building Regulations Approved Document B, fire resisting rolling shutters, across a means of escape, should only be released by a heat sensor. This can include a fusible link or electric heat detector. The closure of rolling shutters in such locations should not be initiated by smoke detectors or fire alarm systems, unless the rolling shutter is also intended to partially descend to form part of a boundary to a smoke reservoir.
(Communication by the management of the company)