This Part of EN 12312 deals with the technical requirements to minimise the hazards listed in clause 4 which can arise during the commissioning, the operation and the maintenance of passenger stairs when carried out in accordance with the specifications given by the manufacturer or his authorised representative. It also takes into account some requirements recognized as essential by the health and safety authorities, aircraft and vehicle manufacturers as well as airlines and handling agencies. This standard applies to: - self-propelled stairs with seated driver (see annex A); - pedestrian controlled stairs; - towable stairs equipped with powered means, e.g. for height adjustment, stabilizers (see annex A); - automatic levelling systems of stairs; for embarking/disembarking of passengers. NOTE 1 Powered should be also understood as manual effort stored in springs or hydraulic accumulators, etc., the dangerous action of which can be produced or can continue after the manual effort has ceased or directly applied manual effort for lifting or lowering loads. NOTE 2 Those clauses of this standard that can apply may also be used as a guideline for the design of towable stairs without powered means. This standard does not apply to pneumatic systems. This standard does not establish requirements for hazards caused by noise and vibration. This Part of EN 12312 is not applicable to passenger stairs which are manufactured before the date of publication by CEN of this standard. This part of EN 12312 is intended to be used in conjunction with EN 1915-1, EN 1915-2, EN 1915-3 (for vehicles) and EN 1915-4. Noise is dealt with in EN 1915-4.