Stair products can be constructed using a wide variety of materials, including; timber, brick, stone, concrete, metal, glass and so on. The requirements for the design of stairs are set out in the approved documents to the building regulations: Approved document K - Protection from falling, collision and impact; Approved document M - Access to and use of buildings (only 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); and Approved document B - Fire safety.