Building Regulations 1992:
Stairs, Ramps and Guards gives provisions for stairways in the design and building of stairways

which form part of the structure and guidance on the aspects of geometry and guarding of stairs.

BS585 Part 1 1989: Woodstairs covers specifications for stairs with closed risers for domestic use,

 including straight and winder flights and quarter or half landings. Appendix A of this standard also details the recommendations for the site fixing of stairs.
BS5395 Part 1 1977: Stairs, Ladders and Walkways covers the design of straight stairs.
BS6180 1982: Code of practice for protective barriers in and about buildings.

DEFINITIONS
Private stairs intended to be used for only one dwelling with a maximum rise of 220mm and a minimum going of 220mm. A maximum pitch of 42° is stipulated for domestic stairs.

Institutional and assembly stairs serving a place where a substantial number of people will gather, with a maximum rise of 150mm and a minimum going of 280mm.

Other stairs covers all other types of buildings, with a maximum rise of 190mm and a minimum going of 250mm.

The normal relationship between the dimensions of the rise and going can be expressed as detailed in Approved Document K, which states that twice the rise plus the going (2R+G) should be between 550mm and 700mm.

Pitch the angle between the pitch line (notional line connecting nosings) and the horizontal. The maximum pitch for domestic stairs is 42°, semi-public stairs, eg factories, offices and common stairs serving more than one dwelling, 38° and public stairs, eg places of public assembly, 33°.

Height of handrails Approved Document K states that flights should have a handrail on at least one side if they are less than one metre wide and on both sides if they are wider than one metre. There is no need for handrails beside the bottom two steps of a stairway. Minimum domestic handrail heights of 900mm for both stairs and landings, public handrail heights should be a minimum of 900mm on stairs and 1100mm on landings.