Corridor Width Calculator - Part M Wheelchair Access & Passing Places

In buildings other than dwellings, Approved Document M Volume 2 (para 3.14b) sets the minimum unobstructed corridor width at 1200mm along its length. Where the width is less than 1800mm, passing places at least 1800mm × 1800mm must be provided so two wheelchair users can pass (para 3.14c); an 1800mm-wide corridor takes two-way traffic without passing places (para 1.11). In dwellings, AD M Volume 1 sets the minimum clear width of every hall or landing at 900mm for an M4(2) accessible and adaptable home (reducible to 750mm at a localised obstruction). For M4(3) wheelchair-user homes, para 3.24 sets a higher minimum: every hallway, approach or landing must be at least 1050mm wide (3.24a), rising to 1200mm where a door is not approached head-on (3.24b).

In a building other than a dwelling, passing places are required where a corridor has an unobstructed width of less than 1800mm and wheelchair users may need to pass each other (Approved Document M Volume 2, para 3.14c). Each passing place must be at least 1800mm long and 1800mm wide. AD M does not set a fixed metric spacing: it says to provide them "at reasonable intervals, e.g. at corridor junctions" — in practice, position them at junctions and changes of direction, within sight of one another. Dwellings do not use 1800mm × 1800mm passing places.

Yes, handrails project from the wall and reduce the effective clear width. A standard handrail projects 45-60mm from the wall surface. For corridors with handrails on both sides, you need to deduct 90-120mm from the structural width. The effective clear width after deductions must still meet the minimum requirements of Part M.

Corridors used as fire escape routes must maintain adequate widths under Approved Document B (fire safety), and their width is influenced by the number of occupants using the route. A wheelchair refuge (temporary waiting space) should be provided at each protected stair for people who cannot use stairs in an emergency. The Approved Document B minimum clear waiting space is 700mm × 1200mm; 900mm × 1400mm is a larger, commonly-recommended size. Each refuge should have an emergency voice communication (EVC) system. Note that escape-route widths under AD B are sized by occupancy and are a separate calculation from the Part M access widths above.

Doors opening into corridors must not reduce the effective width below the minimum when open. Recessed door openings (at least 300mm deep) are recommended so that doors can open without obstructing the corridor. For wheelchair-accessible corridors, doors should have a minimum 300mm nib on the leading edge (pull side) to allow a wheelchair user to reach the handle while clear of the door swing.