Where a compartment wall or compartment floor meets another compartment wall or an external wall, the junction should maintain the fire resistance of the compartmentation. Fire- stopping should meet the provisions of section 6.5.4.

At the junction of a compartment floor with an external wall that has no fire resistance (such as a curtain wall) the external wall should be restrained at floor level to reduce the movement of the wall away from the floor when exposed to fire.

It is important that fire-resistant fire stopping is securely fixed between the floor slab and the external wall.

Compartment walls should be able to accommodate the predicted deflection of the floor above by either:

• having a suitable head detail between the wall and the floor, that can deform but maintain integrity when exposed to a fire; or

• the wall may be designed to resist the additional vertical load from the floor above as it sags under fire conditions and thus maintain integrity.

Note: Where compartment walls are located within the middle half of a floor between vertical supports, the predicted deflection may be assumed to be 40mm unless a smaller value can be justified by assessment. Outside this area the limit can be reduced linearly to zero at the supports. For steel beams that do not have the required fire resistance, reference should be made to SCI Publication 288 Fire safe design: A new approach to multi-storey steel-framed buildings (Second Edition) 2000 (ISBN: 1 85942

169 5).

6.3.3.5 Junction of compartment wall or compartment floor with other walls