Technical Booklet N Drainage·Page 6·78(1)
Application of drainage requirements to small roofs and balconies
Regulation 82 does not apply to drainage systems for roofs or balconies of 6 m² or less, unless that roof or balcony receives rainwater flow from another part of the building.
Regulation 82 shall not apply to a drainage system intended for use in connection with a roof or balcony of 6 m2 or less in area, unless that roof or balcony receives a flow of rainwater from another part of a building.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet N - Drainage.pdf