Vertical circulation provision by passenger lift or lifting platform

Vertical circulation to any storey above or below the principal entrance storey should be provided by means of a passenger lift complying with the provisions of paragraphs 4.25 to 4.38. However where – (a) the space within a building is severely restricted by site constraints; or (b) the installation of a passenger lift would severely affect – (i) the existing accommodation; or (ii) an existing accessible feature of the building, a lifting platform, complying with the provisions of paragraphs 4.25 to 4.33 and 4.39 to 4.45, may be provided to transfer, either independently or with their companions, wheelchair users or people with impaired mobility vertically between storeys.