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Negotiating the Built Environment

Written by Hannah Collins, Access Consultant (July 2020)


Individuals with mobility impairments can incur a number of difficulties when negotiating the built environment. Understanding how individuals who operate aids such as wheelchairs manoeuvre within the built environments assists in comprehending the dimensional requirements around doorways, sanitary facilities, accessways, carparks and other areas of a building.

Within this article we will use diagrams to explore spatial requirements for the following:

  1. Doorways;

  2. Unisex accessible sanitary facilities;

  3. Pathways where a change in direction between 60° - 90° degrees occurs;

  4. Circulation spaces at the ends of accessways; and

  5. Accessible car parking spaces.


To ensure an individual who operates a mobility aid can effectively open a door a move through the doorway, the necessary space needed is determined by a few factors such as the angle of approach, whether the door swings towards or away from the user or if it is a sliding door.

Additionally, the circulation space is required to have a gradient and crossfall not steeper than 1 in 40 as per Clause 13.3.1 of AS 1428.1 (Standards Australia, 2010). This provides an individual operating a mobility chair a stable, level surface on which to stay stationary while operating the door.

The below figures offer a brief insight into how an individual may utilise door circulation spaces. Figure 1 identifies the clearances required under AS 1428.1 where the door swings towards the user. Figure 2 shows how the individual may utilise the space to approach the door, negotiate the door hardware, reposition their chair to move around the door swing and finally move through the doorway.


Figure 1 - Circulation space for front approach; door opens towards user (Standards Australia, 2010)


Figure 2 - User negotiating door – Front approach, door opens towards user.

For further insight into the significance of door clearances, please see Common Accessibility Issues and Misconceptions.

Unisex Accessible Sanitary Facilities


Unisex Accessible Sanitary Facilities are designed to cater for a variety of people and their abilities. The specified circulation space of 1900mm W x 2300mm L is to cater for individuals occupying the 90th percentile wheelchair footprint of 800mm W x 1300mm L (Standards Australia, 2010).

The spatial layout facilitates a variety of transfers/approaches, allowing a person to manoeuvre their mobility aid to transfer on/off the Pan, reach the basin, fixtures and fittings and be able to exit the facility with ease. Adequate space is also required for a person who may have a carer for support, to be able to assist as required. The figures below demonstrate how an individual may utilize the circulation space within a Unisex Accessible Sanitary Facility to transfer onto the Pan.


For further insight into the significance of door clearances, please see Common Accessibility Issues and Misconceptions.

Turning space required for a 90° turn


AS 1428.1 specifies a turning space of 1500mm x 1500mm is required for a turn between 60° - 90° turn (Standards Australia, 2010). This space is required in order to allow users of a variety of mobility aids to reposition and turn themselves around without being impeded while following a path of travel (Institute of Access Training Australia, 2015). The figure below demonstrates one way in which an individual may approach a 90° turn.


Figure 1 - Individual utilising the space specified for a 90° turn

Turning Space Turning space required for a 180° turn


Clause D3.3 (c) of the BCA requires that a turning space must be provided within 2m of the end of an accessway where it is not possible to continue travelling along the accessway (ABCB, 2019). AS 1428.1 requires the turning space for a >90° to 180° turn to be 1540mm x 2070mm (Standards Australia, 2010).

Turning spaces at the end of a “dead-end” corridor are critical for users of mobility aids, to ensure that a person does not have to reverse for an unreasonable distance if they encounter a dead end. The Figure below demonstrates 2 ways in which an individual may approach a 180° turn.


Figure 1     Individual utilising the space specified for a 180° turn

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Understanding the spatial requirements of individuals who utilize mobility aids is essential when designing and constructing a space which is accessible for all. However, in some situations the standard requirements may not consider all factors, including the intended use of a building. In these situations, it may be possible to vary these requirements via an Access Performance Solution.


For more advice about accessibility or to enquire about Access Performance Solution opportunities for your project, please contact us as our friendly staff will be glad to assist you.

Unisex Accessible Sanitary Facilities
Turning Space 90 deg
Turning Space 180 deg
Accessible Ramp
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