Section 1: Stairs and ladders
Scope
1.1 The guidance provided in this document covers internal and external steps and stairs when they are part of the building. Additional guidance is provided in Approved Document M when external stepped access also forms part of the principal entrances and alternative accessible entrances, and when they form part of the access route to the building from the boundary of the site and car parking.
See Approved Document M Section 1 (for buildings other than dwellings) and Section 6 (for dwellings).
Steepness of stairs – rise and going
1.2 Measure the rise and going as shown in Diagram 1.1. (For steps with tapered treads, see also paragraphs 1.25–1.27.)
Diagram 1.1 Measuring rise and going
1.3 In a flight of steps, for all steps use the measurements for rise and going given for the three stair categories in Table 1.1 below. Use any rise between the minimum and maximum with any going between the minimum and maximum, that complies with the relevant note contained in Table 1.1.
Table 1.1
Stepped gangways in assembly buildings
1.4 The guidance provided in this document covers stairs or ramps that form part of the means of access within an assembly building such as a sports stadium, theatre or cinema. However, if steps are part of the gangways to areas for spectators, the gangways may need to be at different pitches to maintain sightlines for spectators – this may affect the main stairs. Apply all of the following guidance.
a. Ensure that the maximum pitch for gangways to seating areas for spectators is 35°.
b. Align the ends of all rows of seats/wheelchair spaces so that the width of the gangway remains the same.
c. Provide transverse gangways to give access from the side to storey exits (vomitory exits) within the body of a seating layout.
d. Ensure that transverse gangways and radial gangways in auditoria with tiered seating do not cross. Offset the connections between transverse gangways and radial gangways so that the flow of people to the exits is smooth.
e. In stepped tiers, use the following measurements for each step in the gangway:
- minimum height: 100mm
- maximum height: 190mm
If there are two or more rises to each row of seats, make each step an equal height.
f. In a tier that is uninterrupted by cross-gangways, and where the pitch exceeds 25°, use a maximum number of steps of 40.
g. Where an exit is approached from a stepped gangway, place a landing the width of the exit and a minimum of 1100mm deep immediately in front of the exit doors.
h. For stepped side gangways, provide a handrail in accordance with paragraphs 1.34 and 1.36.
i. In stepped tiers, maintain the same level between the seatway and the nearest step.
j. Gangways should not be less than 1100mm wide unless used by not more than 50 persons, in which case gangways should be a minimum of 900mm.
Construction of Steps
For all buildings
1.5 Have level treads on steps, ensuring that the rise and going of each step are consistent throughout a flight of steps and are in accordance with Table 1.1.
For buildings other than dwellings
1.6 Use risers that are not open.
NOTE: The benefits of a riser that is not open are as follows:
- It removes the possibility of the front of a foot or a walking aid being caught underneath a tread during ascent, possibly causing a fall.
- It avoids the feeling of insecurity people get when looking through open risers on a stair.
1.7 For steps, apply both of the following guidance:
- Make step nosings apparent: use a material that will contrast visually, a minimum of 55mm wide, on both the tread and the riser.
- Avoid, if possible, step nosings that protrude over the tread below. If the nosing protrudes, ensure that this is by no more than 25mm (see Diagram 1.2).
1.8 If the soffit beneath a stair is less than 2m above floor level, protect the area beneath a stair with one of the following:
- Guarding and low level cane detection.
- A barrier giving the same degree of protection.
For dwellings
1.9 Steps may have open risers if they comply with both of the following guidance.
- Overlap treads by a minimum of 16mm.
- Construct the steps so that a 100mm diameter sphere cannot pass through the open risers.
- For common access areas in buildings that contain flats
1.10 Provide a stair with steps that comply with all of the following guidance.
- Make step nosings apparent: use a material that will contrast visually, 50mm to 65mm wide on the tread and 30mm -to 55mm on the riser.
- Use a suitable tread nosing profile, as shown in Diagram 1.2.
- Use risers which are not open.
Diagram 1.2 Examples of suitable tread profiles
Headroom for Stairs
For all buildings
1.11 On the access between levels, provide the minimum headroom shown in Diagram 1.3.
Diagram 1.3 Minimum headroom
For buildings other than dwellings and for common access areas in buildings that contain flats
1.12 Provide all means of escape routes with a minimum clear headroom of 2m, except in doorways.
For loft conversions in dwellings
1.13 Where there is not enough space to achieve the height shown in Diagram 1.3, provide the reduced headroom shown in Diagram 1.4.
Diagram 1.4 Reduced headroom for loft conventions
Width of flights of stairs
For buildings other than dwellings
1.14 For stairs that form part of means of escape, refer also to Approved Document B: Fire safety, Volume 2 – Buildings other than dwellinghouses.
1.15 For flights of stairs, provide all of the following:
a. A minimum stair width between enclosing walls, strings or up stands of 1200mm.
b. A minimum width between handrails of 1000mm.
c. If the flight is more than 2m wide, divide it into flights a minimum of 1000mm wide, as shown in Diagram 1.5
d. For access for maintenance, see paragraph 1.42.
For dwellings
1.16 In exceptional circumstances where severely sloping plots are involved, a stepped change of level within the entrance storey may be unavoidable. In those instances ensure that stairs within the entrance storey of a dwelling have flights with a minimum stair width of 900mm.
Diagram 1.5 Dividing flights
Length of flights of stairs
For all buildings
1.17 If stairs have more than 36 risers in consecutive flights, make a minimum of one change of direction between flights, as shown in Diagram 1.6.
Diagram 1.6 Change of direction in flights
For buildings other than dwellings and common access areas in buildings that contain flats
1.18 Comply with all of the following:
a. Do not have single steps.
b. For flights between landings the maximum number of risers should be:
utility stairs – 16 risers
general access stairs – 12 risers, but exceptionally no more than 16 in small premises where the plan area is restricted
stairs for access for maintenance, see paragraph 1.42.
Landings for stairs
For all buildings
1.19 For means of escape requirements, refer also to Approved Document B: Volume 1 – Dwellinghouses, and Volume 2 – Buildings other than dwellinghouses.
1.20 At the top and bottom of every flight, provide landings the width and length at least as great as the smallest width of the flight (see Diagram 1.6).
1.21 A landing:
a. may include part of the floor of the building
b. should be kept clear of permanent obstructions
c. may have doors to cupboards and ducts that open over a landing at the top of a flight, as shown in Diagram 1.7, but only when they are kept shut or locked shut when under normal use.
Diagram 1.7 Cupboard onto landing
1.22 Landings should be level, with the following exception:
A landing at the top or bottom of a flight that is formed by the ground may have a gradient, provided that:
a. the maximum gradient along the direction of travel is 1:60
b. the surface is paved ground or otherwise made permanently firm.
For buildings other than dwellings
1.23 Provide all of the following:
a. An unobstructed length a minimum of 1200mm on each landing.
b. Doors that do not swing across landings, except where they comply with paragraph 1.21c.
c. For access for maintenance, see paragraph 1.42.
For dwellings
1.24 A door may swing across a landing at the bottom of a flight, but only as shown in Diagram 1.8.
Diagram 1.8 Landings next to doors in dwellings
Special stairs
Tapered treads
1.25 For the rise and going, comply with paragraphs 1.2 and 1.3. For the going of tapered treads, use the measurements shown in Diagram 1.9.
1.26 For consecutive tapered treads, use the same going.
1.27 If a stair consists of straight and tapered treads, ensure that the going of the tapered treads is not less than the going of the straight treads.
Diagram 1.9 Measuring tapered treads
Spiral and helical stairs
1.28 Design spiral stairs and helical stairs in accordance with BS 5395-2.
Alternating tread stairs in dwellings
1.29 You may use alternating tread stairs – in one or more straight flights – only in a loft conversion, and only when there is not enough space for a stair that satisfies paragraphs 1.2–1.24, and the stair is for access to only one habitable room and, if desired, a bathroom and/or a WC (although this must not be the only WC in the dwelling).
1.30 The construction of an alternating tread stair should comply with all of the following.
a. Comply with Diagram 1.10.
b. Make alternating steps uniform with parallel nosings.
c. Have slip-resistant surfaces on treads.
d. Ensure that the tread sizes over the wider part of the step are in line with the dimensions in Table 1.1.
e. Comply with paragraph 1.9b.
f. Provide a minimum clear headroom of 2m.
Diagram 1.10 Alternating tread stair
Fixed ladders
In dwellings
1.31 Do not use retractable ladders as means of escape. Refer to Approved Document B: Volume 1 – Dwellinghouses, and Volume 2 – Buildings other than dwellinghouses.
1.32 You may use a fixed ladder – with fixed handrails on both sides – only for access in a loft conversion that contains one habitable room, and only when there is not enough space without alteration to the existing space for a stair that satisfies the guidance for dwellings in paragraphs 1.2–1.24.
For industrial buildings
1.33 Design and construct stairs, ladders and walkways, as appropriate, in accordance with BS 5395-3 or BS 4211.
Handrails for stairs
For all buildings
1.34 Provide handrails in accordance with all of the following:
a. Position the top of the handrail 900mm to 1000mm from the pitch line or floor.
b. The handrail may form the top of a guarding if you can match the heights.
c. If the stairs are 1000mm or wider: provide a handrail on both sides.
For buildings other than dwellings and for common access areas in buildings that contain flats and do not have passenger lifts
1.35 Provide suitable continuous handrails, as dimensioned in Diagram 1.11 (for blocks of flats) and Diagram 1.12 (for buildings other than dwellings), in accordance with both of the following:
a. On each side of the flights.
b. On each side of the landings.
Diagram 1.11 Key dimensions for handrails for common stairs in blocks of flats
For buildings other than dwellings
1.36 Provide handrails in accordance with all of the following (in addition to paragraph 1.34).
a. Where there is full-height structural guarding, if you provide a second (lower) handrail, the vertical height from the pitch line of the steps (or the surface of the ramp) to the top of the second (lower) handrail should be 600mm.
b. Use a continuous handrail along the flights and landings of a ramped or stepped flight.
c. Ensure that handrails do not project into an access route.
d. Ensure that the handrail will contrast visually with the background against which it is seen, without being highly reflective.
e. Use a surface for the handrail that is slip-resistant and which, in locations subject to extremely cold or hot temperatures, does not become excessively cold or hot to touch. In areas where resistance to vandalism or low maintenance are key factors, use of metals with relatively low thermal conductivity may be appropriate.
f. Finish the end of the handrail in a way that reduces the risk of clothing being caught.
g. Use the handrail profile shown in Diagram 1.13.
Diagram 1.12 Key dimensions for handrails for stairs in buildings other than dwellings
In dwellings
1.37 In exceptional circumstances where severely sloping plots are involved, a stepped change of level within the entrance storey may be unavoidable. In those instances, if a flight comprises three or more risers, provide a suitable continuous handrail in accordance with both of the following.
a. On each side of the flight.
b. On each side of any intermediate landings.
Diagram 1.13 Handrail design
Guarding of stairs
For all buildings
1.38 Design the guarding to be the height shown in Diagram 3.1.
1.39 In a building that may be used by children under five years of age, construct the guarding to a flight of stairs to do both of the following:
a. Prevent children being held fast by the guarding: ensure that a 100mm sphere cannot pass through any openings in the guarding.
b. Prevent children from readily being able to climb the guarding.
For buildings other than dwellings and for common access areas for buildings that contain flats
1.40 Provide guarding at the sides of flights and landings when there are two or more risers.
In dwellings
1.41 Provide guarding at the sides of flights and landings when there is a drop of more than 600mm.
Access for maintenance
For buildings other than dwellings
1.42 Where the stairs or ladders will be used to access areas for maintenance they should comply with one of the following:
a. If access will be required a minimum of once per month: follow provisions such as those for private stairs in dwellings or for industrial stairs and ladders in BS 5395-3.
b. If access will be required less frequently than once a month: it may be appropriate, for example, to use portable ladders. The Construction (Design and Management) Regulations 2007 give provisions for safe use of temporary means of access.
