Posted By Gary Cutter Does anyone know what is the recommended maximum restrained opening of windows in hi-rise buildings for domestic use to prevent falls from height? I’ve been told that the industry standard is 100mm to stop children falling. Building Regs doesn’t offer much guidance and neither does the Workplace Regulations so I’m stuck. Help would be appreciated.

Posted By Ken Taylor The '100mm standard' pops up in various publications and standards. With regard to window openings, Approved Document N3 refers to suitable opening limiters or guarding where there is a danger of persons falling through and tells us to see Approved Document K. Approved Document K3 says, with regard to guarding by walls, parapets, ballustrades or similar, that, where buildings are likely to be used by children under 5 years, guarding should prevent them being held fast and that the construction should be such that a 100mm sphere cannot pass through any opening. I know that this isn't as clear or specific as we would like for window opening but it should be usable to make a case for a level of safe provision.