Fire Rated Systems must replicate the system adopted in the Standard Fire Resistance Test. It is not advisable to depart from the Manufacturers installation instructions and install a FR Ceiling System, directly to the purlins if the system has been tested in a Suspended mode only. LAF can offer Ceiling systems, which have been tested (SI-1589) in contact with the purlins and achieved an FRL of 240/240/240.
Caution should be exercised if services are to be attached/suspended from any Fire Rated Ceiling system. Unless these extra loads (services) were included in the Tested prototype, added structural supports are required to independently carry the additional load. This detail should be carefully planned as Authorities may consider the projecting parts of these structural supports (bracket, cleats, clips etc.) as penetrations and reject the integrity of the Ceiling System. LAF’s systems cater for penetrating suspension clips for secondary ceilings and brackets used to suspend services below the Fire Rated Ceiling. These suspension clips/brackets must be attached to the Roof Purlins, or other structural members, and installed by the Fire Spraying Contractor, ensuring unrelated trades (Spraying, Secondary Ceiling and other Services) do not interfere with each other.
The floor joists of the floor requiring upgrading must be equal or larger in size than the ones that were submitted to the Standard Fire Test for the relevant LAF systems. A practicing Structural Engineer may review the structural parameters of the floor with a view to reducing/redistributing the loads and ensure the system complies with the relevant code(s).
If Partitions are present and they abut the underside of the floor these must have equal FRL as the floor system. If not, the partitions should be cut back and finished 100 mm clear of the floor joists to allow the Fire Rated Ceiling system to carry uninterrupted throughout the floor, thus preventing Fire from exploiting the partition.
Special attention is required for all types of penetrations through Timber Floor systems. In some cases these Services penetrations, should be totally isolated with proven non-combustible lightweight mortars to the immediate vicinity of the Fire collars. Please refer to LAF for further details.
With existing buildings being refurbished it is common to have an old ceiling in place. These are costly to remove, create numerous problems with their disposal and slow down the construction program. The LAF Vermitex system does not require existing ceilings to be removed, however due care must be taken to ensure that the Fire upgrading Ceiling installed over the existing ceiling is fixed through to the Floor joists and not to the existing Ceiling battens.