British Strandard Categories for spiral staircases
What are the Building Regulations for Spiral Staircases in the UK?
Spiral and helical stairs regulations
Part K of the Building Regulations provides the guidelines for ensuring occupants or visitors to a house are protected against falling, collision or impact.
In Approved Document K 1.28 it says:
“Design spiral and helical stairs in accordance with BS 5395-2”
All the spiral and helical staircases that we manufacture at Spiral UK are compliant with British Standards Document BS 5395 Part II.
Spiral staircase or helical stairs regulations for residential properties
The staircase categories relating to residential spiral or helical staircases tend to be A small private stair or B private stair. Part B & M of the Building Regulations for staircases don’t tend to apply to residential properties.
Category A – small private stair
This type of spiral or helical stairs is intended for use by a limited number of people who are generally familiar with the staircase. For example, an internal stair in a dwelling serving one room not being a living room or a kitchen, an access stair to an office not used by the public, or spiral fire escape stairs for a small number of people.
- Minimum and maximum rise per tread: 170-220mm
- Minimum clear width* between core pole & handrails: 600mm
- Minimum going from the centre of the tread: 145mm
Category B – private stair
In addition to a category A stair, this private stair can also provide the main access to the upper floor of a private dwelling.
- Minimum and maximum rise per tread: 170-220mm
- Minimum clear width between core pole & handrails: 800mm (900 in Scotland)
- Minimum going from the centre of the tread: 190mm
Spiral staircase regulations for commercial and public use
Category C small semi-public, D semi-public or E public stairs tend to be for staircase projects in commercial and public spaces.
It is important to note that where there is a contradiction between BS 5395 Part II and Part B and M of the Building Regulations, Part B and M take precedence.
Category C – Small Semi-Public stair
This type of stair is intended for use by a limited number of people some of whom maybe unfamiliar with it. Typical examples are stairs in offices, a factory or for a stair serving more than one dwelling.
- Minimum and maximum rise per tread: 170-220mm
- Minimum clear width between core pole & handrails: 800mm (900 in Scotland)
- Minimum going from the centre of the tread: 230mm
Category D – Semi-Public stair
This category of stair is intended for use by larger numbers of people some of whom maybe unfamiliar with it. It suits larger floor areas in a factory, shop or office or can be a common stair serving more than one dwelling.
- Minimum and maximum rise per tread: 150-190mm
- Minimum clear width between core pole & handrails: 900mm (900 in Scotland)
- Minimum going from the centre of the tread: 250mm
Category E – Public stair
Public stairs are for use by large numbers of people at one time and used in places of public assembly.
- Minimum and maximum rise per tread: 150-190mm
- Minimum clear width between core pole & handrails: 1000mm (900 in Scotland)
- Minimum going from the centre of the tread: 250mm
