Building Construction Handbook, Eighth Edition

Institutional and Assembly Stairs ~ Serving a place where a
substantial number of people will gather.

minimum going, 280 mm (may

reduce to 250 mm if the building

floor area <100 m^2 ),

maximum, 340 mm

The maximum pitch for gangways

with seated spectators in assembly

buildings is 35ƒ.

rise 135

to 180 mm

Other stairs ~ All other buildings.

minimum going, 250 mm

maximum, 320 mm

rise 150

to 190 mm

Common to both functional

groups: twice the rise plus

the going, 550 to 700 mm.

Alternative guidance: BS 5395-1: Stairs, ladders and walkways. Code of
practice for the design, construction and maintenance of straight stairs
and winders.
The rise and going in both situations may be subject to the requirements
of Approved Document M: Access to and use of buildings. AD M will take
priority and the following will apply:

Going (external steps) ~ 280 mm minimum (300 mm min. preferred).
Going (stairs) ~ 250 mm minimum.
Rise ~ 170 mm maximum.

Other AD M requirements for stairs:

Avoid tapered treads.
Width at least 1200 mm between walls, strings or upstands.
Landing top and bottom, minimum length not less than stair width.
Handrails both sides; circular or oval preferred as shown on next page.
Door openings onto landings to be avoided.
Full risers, no gaps.
Nosings with prominent colour 55 mm wide on tread and riser.
Nosing projections avoided, maximum of 25 mm if necessary.
Maximum 12 risers; exceptionally in certain small premises 16.
Non-slip surface to treads and landing.

Public and General Use Stairs