This standard has been prepared in order to specify requirements and determination methods for newly certificated commercial passenger aircraft programmes. It may also apply to current production aircraft, should it be shown to be technically feasible and economically justifiable. The standard distinguishes between safety, health and comfort conditions for passengers and crew under a variety of phases of flight, including embarkation and disembarkation. The standard is intended for use in design, manufacturing, maintenance and normal operation of commercial aircraft. The standard committee has tried to make the standard performance based. This means that only parameters of direct effect on safety, health and comfort of aircraft occupants are considered. Prescriptive design solutions, such as ventilation flow rates, are not described in the clauses of the standard. Nevertheless, in exceptional cases, current technology is used in notes, appendices and/or recommendations to describe available solutions that may meet the objectives of individual requirements of the standard. Regulatory bodies may apply this standard or parts thereof.