Stair Safety Overview - BCA Standards for staircase rise and going

The combination of riser and going dimensions results in the pitch of the stairs. The maximum pitch for the elderly people, young children, and people with mobility impairments is recommended at between 33 degrees and 35 degrees. Pitch angles greater than 35 degrees are less suitable for elderly and disabled people. Slope is now recommended with respect to clear definitions of riser and treads dimensions. The formula for relating the depth of treads and the height of risers was developed by Francois Blondel, a French architect, in 17th century. Based on observations of people’ gaits, the formula suggested that twice the riser height plus the tread depth should be between 610 mm and 635 mm. While there have been variations across the countries in applying this formula, it has been widely adopted in stair building.

The current Australian building standards also applies the formula, 2R + G, to quantify the relationship between riser (R), going (G), and slope. In principle, a lower stair pitch is recommended to minimise the likelihood of falls (Standards Australia, 2008). A steeper stair pitch might cause severe injury by failing to protect stair users from a longer fall.

In the BCA, riser and going dimensions in buildings are given as:

* stairways which are not part of a required exit and to which the public does not normally have access

The handy illustrations below provide a convenient to reference to limits on both standard and spiral staircases. When using, remember that 250mm is the minimum going for public stairs.