TP(a) and TP(b) plastic rooflights – Limitations on use and boundary distance

Table 5.9 TP(a) and TP(b) plastic rooflights – Limitations on use and boundary distance Minimum classification on lower surface (1) | Space which rooflight can serve | Minimum distance (m) from any point on relevant boundary to rooflight with an external surface classification of TP(a) | TP(b) 1 TP(a) rigid | Any space except a protected stairway | 6(2) | Not applicable 2 TP(b) (a) Balcony, verandah, carport, covered way or loading bay which has at least one longer side wholly or permanently open (b) Detached swimming pool (c) Conservatory, garage or outbuilding, with a maximum floor area of 40 m2 | Not applicable | 6 (d) Circulation space(4) (except a protected stairway) (e) Room(4) | Not applicable | 6(3) Notes: (1) As required by paragraph 3.14. (2) No limit in the case of any space described in items 2(a), (b) and (c). (3) The rooflight should also comply with Diagram 5.6. (4) Single skin rooflight only, in the case of non-thermoplastic materials. Rooflights may have upper and lower surfaces with different properties if they have double skins or are laminates of different materials – in which case the more onerous distance applies. Where paragraph 4.21(a) applies rooflights should be at least 1.5 m from the compartment wall.