Window Safety and Restrictors

What This Requirement Covers

Approved Document K requires measures to prevent falls from windows, particularly in buildings where children may be present. Window restrictors limit the opening of a window to prevent a person from falling through the opening, while still allowing the window to be opened fully for emergency escape or cleaning.

Key Requirements

When Window Restrictors Are Required

1. Windows with a cill height below 800 mm above the floor in any building where the drop outside exceeds 600 mm
2. In buildings where children under 5 may be present (dwellings, schools, nurseries), restrictors are required on all openable windows above ground floor unless the window is required for emergency escape

Restrictor Requirements

1. Window restrictors must limit the opening to no more than 100 mm in the first instance
2. The restrictor must be robust enough to resist a child leaning against it
3. A key-operated or two-handed release mechanism must be provided to allow the window to be opened fully (for emergency escape, cleaning, or ventilation)
4. The release mechanism must be operable by an adult without tools

Emergency Escape Windows

1. Where a window is designated as an emergency escape window (Approved Document B), it must be capable of opening fully
2. The restrictor must not prevent the window from being opened for escape in an emergency
3. A key-release restrictor is acceptable provided the key is readily available (though not to young children)

Guarding Alternative

1. Instead of window restrictors, guarding (a rail or barrier) can be provided in front of the window to prevent falls
2. The guarding must be at least 800 mm high and must not be climbable

Practical Compliance Tips

1. Check all windows with low cill heights at the design stage and specify restrictors where required
2. Specify restrictors that are robust and tamper-resistant; cheap restrictors can fail under load
3. Ensure the restrictor allows the window to be opened fully for escape; a restrictor that prevents full opening on an escape window is non-compliant with Part B
4. In new dwellings, consider specifying windows with integrated restrictors from the factory
5. Brief occupants on how to release the restrictor for cleaning and emergency escape
6. In schools and nurseries, use restrictors that cannot be released by children
7. Inspect restrictors annually and replace any that are damaged or not functioning correctly