Curtain Wall Systems
AIM Wall Cavity Barrier is suitable for use in curtain wall cladding systems. The performance of the fire barrier is dependent upon the integrity and stability of the cladding system in the region of the barrier. Should the curtain wall cladding bow or distort significantly in a fire, the gap that the fire barrier is filling may widen causing loss of integrity. Where this is a possibility, the cladding system must be attached with steel brackets to the structural floor, close to the fire barrier, so the distance of separation cannot increase. The system manufacturer of the curtain wall cladding system must confirm its suitability for use with fire barrier for the fire resistance period required
Fire Performance
Thickness is measured as the distance between one compartment and the next, which the fire stop or barrier is separating. The 60 minute barrier has butt end joints. The 120 minute barrier has lap end joints.
SAFETY NOTE - CLIPS
Clips must not be installed with the sharp points left exposed at any time, due to risk of serious injury.
Acoustic Rating
When installed above a partition and where an imperforate 12.5mm plasterboard ceiling is installed to abut the partition below on both sides, the room to room sound reduction, on the path of the Fire Stop Block, will be at least 47dB – average sound reduction index.
Installation
AIM Wall Cavity Barrier is push fitted into place; it must fit tightly and completely with approximately 5% compression. If the barrier is also being used to prevent air leakage, it requires taped joints and intumescent mastic to the linear edges to create a seal. Wall Cavity Barrier is available notched and in non standard lengths.
Clips
Clips are required when the barrier is installed horizontally. They may be omitted when the barrier is installed vertically into cavities less than 250mm, provided the barrier is supported at its base. Two clips per length are required for cavities up to 400mm, three clips per length are required for cavities over 400mm (see table).
Clips are supplied as flat strips, prenotched to allow them to be easily formed on site and with prestressed snap off points to enable the correct length to be created.
Fitting
For horizontal barrier, the clips should be embedded in the barrier to approximately ¾ barrier width prior to fitting so that the top leg of the clip is level with the top of the barrier. The barrier is pushed into the cavity until the top leg of the clips touches the floor slab, and the top surface of the cavity barrier is flush with the slab.
For vertical barrier, where clips are used these may have to be fixed to the inner wall, before the barrier is installed. When the barrier has to be installed before the outer wall layer, the barrier may require retaining straps to prevent it falling off prior to completion of the wall.
Butt end joints must be tight. The ends of adjoining barriers must be fitted in contact for the full barrier width.
Caution
If the gap to be filled is between two building components which might separate in a fire, the two components must be connected with steel brackets to ensure that the distance of separation cannot increase (see notes on Curtain Wall Systems page 6).
Masonry Cavity Walls
Horizontal Barrier: Bed the fixing clips into the joints in the internal leaf. A damp proof membrane or cavity tray must be installed into the cavity wall immediately above, and to the outside of, the fire barrier. Clips may be omitted in masonry cavity walls, provided the barrier is installed immediately above a row of metal wall ties where these are spaced at no more than 500mm centres.
