This part of ISO 9386 specifies the safety rules, dimensions and functional operation for permanently installed power-operated stairlifts intended for use by persons with impaired mobility, for seated, standing and wheelchair users moving in a substantially inclined plane. It is restricted to stairlifts a) which travel between fixed levels over a staircase or an accessible inclined surface (see note 1); b) whose rated speed does not exceed 0,15 m/s; c) whose rail inclination does not exceed 75° from the horizontal; d) whose carriage is directly retained and guided by a rail or rails (see note 2). NOTE No enclosure for the path of the stairlift is required. This part of ISO 9386 does not specify every general technical requirement for all aspects of the electrical, mechanical or building construction. As far as possible, this part of ISO 9386 specifies only the requirements that materials and equipment need to meet in the interests of safety and functional operation. Requirements are also included for protection against harmful influences which may be experienced by equipment installed in external locations.