Technical Booklet E Fire Safety·Page 121·4.40(e)
Cavity barriers in double-skinned profiled insulated roof sheeting
Specifies when cavity barriers are required in double-skinned profiled insulated roof sheeting, with reference to Diagram 4.9 showing acceptable configurations without cavity barriers and conditions requiring them.
(e) between double-skinned, profiled, insulated, roof sheeting provided that –
(i) the sheeting is a material of limited combustibility;
(ii) both surfaces of the insulation layer have a surface spread of flame classification not lower than Class 1 (National class) or Class C-s3,d2 (European class); and
(iii) the insulation is in contact with the inner and outer skins of sheeting as shown in Diagram 4.9(a).
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet E - Fire Safety.pdf