Limitation on areas and spacing of certain thermoplastic rooflights

Limitation on areas and spacing of certain thermoplastic rooflights rooflight max. area 5 m² 3 m minimum between any two rooflights in any direction Notes: Or group of rooflights amounting to not more than 5 m². Class 3 (National class) or Class D-s3,d2 (European class) rooflights to rooms in non-residential purpose groups may be spaced 1.8 m apart provided that the rooflights are evenly distributed and do not exceed 20% of the floor area of the room. 1 Surrounding roof covering to be a material of limited combustibility for at least 3 m distance. 2 Where paragraph 4.21(a) applies rooflights should be not less than 1.5 m from the compartment wall.