Building Regulations: Technical Standards

S3 Stairs and ramps

GENERAL STANDARDS FOR ALL STAIRS

S3.1 A stair must be constructed in any of the following ways -

a.

a straight flight in accordance with S3.2 to S3.11

b.

a flight consisting partly of straight and partly of tapered treads in accordance with S3.2 to S3.8, and S3.10 to S3.14;

c.

a flight consisting wholly of tapered treads in accordance with S3.6 to S3.8, and S3.15;

d.

an industrial stair or fixed ladder in accordance with S3.26;

e.

a stair or fixed ladder in an agricultural building in accordance with S3.27;

f.

a stair forming part of a sloping gangway in a building of purpose group 5 in accordance with S3.28.

RULES OF MEASUREMENT

S3.2 The rise and going must be measured in accordance with the diagram to this standard -

Diagram to S3.2: Stair measurement

Diagram S3.2 stair measurement

 

Note:

The number of tapered treads shown is indicative only; there must be at least 3 treads in total in a flight, but the number of tapered treads is unrestricted.

RISE, GOING AND PITCH OF FLIGHTS IN STAIRS

S3.3 The maximum rise, minimum going and pitch of flights in stairs must be in accordance with the table to this standard -

Table to S3.3: Rise, going and pitch of flights in stairs

Table S3.3 Rise, going and pitch of flights in stairs

Note:

1.

In the case of tapered treads, subject to S3.12 to S3.14.

2.

The combination of maximum rise and minimum going will result in a pitch steeper than this.

S3.4 The width of a stair, measured between handrails and clear obstructions, must be at least 1 metre,

except -

a.

the width of a private stair may reduce to at least -

 

i

900mm where it is within the accessible storey , or

 

ii

600mm where it serves only sanitary accomodation and/or one room, other than a living room or kitchen, or

 

iii

800mm elsewhere; and

b.

stringers and newels may each project not more than 30mm into the width; and

c.

a stair lift projecting into the width may be fitted to a stair within a dwelling.

Note:

There are additional stair width requirements for escape stairs in Part E.

S3.5 The aggregate of the going and twice the rise must be at least 550mm and not more than 700mm.

S3.6 A flight must have uniform rises, each at least 75mm.

S3.7 The depth of a tread must not be less than the going.

S3.8 In a flight, or in that part of a flight which is straight, the going measured along the centre line of the flight must be uniform.

LENGTH OF FLIGHTS

S3.10 A flight must have -

a.

not more than 16 rises; and

b.

at least 3 rises,

except -

there may be less than 3 rises -

 

i. between an external door of a building and the ground, balcony, conservatory, porch or private garage; or

 

ii. in a stepped ramp; or

 

iii. wholly within an apartment within a dwelling; or

 

iv. wholly within sanitary accomodtion within a dwelling; or

 

v. between a landing and an adjoining level where the route of travel from the adjoining level to the next flight changes direction through 90 degrees.

RISERS AND NOSINGS

S3.11* A stair serving a storey to which access for disabled people is required by S2.6 must have -

a.

risers profiled to minimise tripping; and

b.

nosings distinguishable through contrasting colour or tone.

Note:

This standard does not apply to a private stair in a dwelling.

FLIGHTS CONSISTING PARTLY OF STRAIGHT AND PARTLY OF TAPERED TREADS

S3.12* In that part of a flight consisting of tapered treads, the going of the tapered treads must be uniform and must not be less than the going of the straight treads. At the inner end of the tread the going must be at least 50mm.

S3.13 In a flight less than 1 metre wide the going must be measured at the centre line of  the flight as in S3.2.

S3.14 In a flight 1 metre wide or more the going must be measured at the two points 270mm from each end of the tread as in S3.2 and the minimum going must be at least the going of the straight treads.

FLIGHTS CONSISTING WHOLLY OF TAPERED TREADS

S3.15* A flight consisting wholly of tapered treads must be constructed so as to give safe passage. The requirements in S3.18 to S3.25 for landings, so far as they apply to intermediate landings between floors, and for handrails, and for headroom, do not apply to such stairs.

PEDESTRIAN RAMPS

S3.16 The maximum gradient and maximum length of a flight of a ramp for use by pedestrians must be in accordance with the table to this standard -

Table to S3.16: Gradient and length of aflight in a ramp

 

Table to S3.16 gradient and length of a flight in a ramp

S3.17 A ramp must have -

a.

a width at least the minimum required for the equivalent type of stair in S3.4; and

b.

a raised kerb at least 100mm high on any exposed side of a flight or landing,

except -

 

a ramp serving a single dwelling.

LANDINGS

S3.18 A landing, level except for any necessary slope for drainage, must be provided at the top and bottom of every flight of a stair or ramp.

except -

a.

a landing may be common to two or more flights; and

b.

a landing is not required to a flight between the external door of

 

i. a building and the ground, balcony, conservatory, porch or private garage, where the door slides or opens in a direction away from the flight and the aggregate rise is not more than 600mm; or

 

ii. a dwelling or private garage ancillary to a dwelling and the ground, balacony, conservatory, or porch, other than a door required to be accessible for disabled people under Part Q, where the change in level is not more than 170mm.

S3.19 The unobstructive length of a landing, measured along its centre line and clear of any door swing, must be at least 1.2 metres,

except -

in a dwelling

a. the length of a landing may reduce to at least 900mm; and

b. a door may open onto a landing between flights such that at any angle of swing it does not diminish the effective width of the landing to less than the width of the stair or ramp; and

c. a door may open onto the bottom landing of a flight such that at any angle of swing a clear length of at least 400mm is left across the full width of the landing.

HANDRAILS

S3.20 A stair or ramp for a change in level of more than 600mm, or a ramp longer than 2 metres, must have a handrail on both sides of every flight,

except -

a. no handrail is required on a ramp serving a single dwelling where the change of level is no more than 600mm; and

b. a private stair in a dwelling connecting two or more storeys may have a handrail on only one side.

S3.21 A stair or ramp more than 1.8 metres wide must be divided by a handrail, or handrails, in such a way that each section is at least 1.1 metres and not more than 1.8 metres wide,

except -

a. a stair or ramp serving a single dwelling; or

b. a stair between an entrance door to a building and ground level which does not form part of an escape route.

S3.22 A handrail must be fixed at a height of at least 840mm and not more than 1 metre, measured vertically above the pitch line of the flight or surface of the landing.

S3.23 A handrail must extend at least 300mm beyond to top and bottom of a flight and have a profile and projection that allows a firm grip.

except -

where the handrail serves a single dwelling.

S3.24 The ends of a handrail must be wreathed when not forming part of a protective barrier,

except -

where the handrail serves a single dwelling.

HEADROOM

S3.25 A stair, ramp or landing must have a clear headroom of at least 2 metres extending over the whole of the width, measured vertically from the pitch line of the flight or the surface of the landing, as shown in the diagram to this standard -

Diagram to S3.25: Measuring headroom

Diagram S3.25 measuring headroom

INDUSTRIAL STAIRS AND FIXED LADDERS

S3.26* An industrial stair or fixed ladder serving areas requiring limited access in any building must be contstructed so as to offer safe passage.

STAIRS AND FIXED LADDERS INAGRICULTURAL BUILDINGS

S3.27* A stair or fixed ladder in an agricultural building must be constructed so as to offer safe passage.

STEPS IN SLOPING GANGWAYS

S3.28 In a building of purpose group 5 where steps form part of sloping gangways serving areas for audiences or spectators each step must have a rise of at least 125mm and not greater than 190mm.