Lateral circulation refers to movement throughout one storey of a building. The key principles of accessible lateral circulation are:

• unimpeded movement
• unobstructed routes that are free from obstacles and hazards
• routes that are clearly indicated using good signage and other wayfinding devices

Wayfinding

The use of materials, floor surfaces, colours, lighting, tactile clues on handrails and sounds can all be used to help identify and differentiate routes.

In new buildings, the internal layout should seek to avoid narrow corridors, awkward doors, changes of level and tortuous layouts. Such features are common within existing building stock, and often require less effective retrospective fittings or changes.

Corridors

Corridors should be as short as possible to facilitate orientation, and routes should be unobstructed. Floor surfaces must be safe, firm and should allow wheelchair users to move freely. Signage and colours should be used to aid wayfinding.

The diagram below indicates the design detail that helps to create good circulation routes in a building.

Internal doors

Doors should only be used where necessary (such as for noise prevention, or fire or security purposes), as they slow down circulation through a building. The minimum effective clear width of internal doors varies according to the angle of approach and the width of access (see table below).

Minimum effective clear width of doors as recommended in Approved Document M:

Doors should be as easy to open as possible. Approved Document M recommends that the opening force of doors should not exceed 20 Newtons. Heavy doors should be replaced with automatic doors where possible, or replaced with doors that are lighter to open (while still meeting fire regulations requirements). Automatic door closers are sometimes adjustable, so see whether adjustment is possible before recommending any major changes.

Doors should be clearly identified by visual contrast with the walls. They should include vision panels and door furniture that can be operated even by someone with limited manual dexterity. The door handle should also contrast visually with the door.

Changes in level

Sometimes, small changes in level may occur within a storey, usually due to existing site conditions. Any change in level within a storey that requires stairs must also be accompanied by an alternative accessible route via a ramp or platform lift.

Although platform lifts are not ideal, they may be acceptable in existing buildings to overcome changes in level, but only where passenger lifts and ramps are not possible because of space constraints.

Platform lifts should be:

• located adjacent to the stairs with which they are associated
• designed for independent use, with clearly visible controls at the right height
• fitted with an emergency alarm
• able to accommodate a range of users, including people in powered wheelchairs

The diagram below indicates the design of a short-rise platform lift. However, if the vertical travel distance exceeds 2m, or the lift penetrates the floor, there should be a liftway enclosure.