This part of ISO 7240 specifies the design, installation, commissioning and service requirements for a sound system for emergency purposes (s.s.e.p.; see ISO 7240-1:2005, Figure 1, item C), which is primarily intended to broadcast information for the protection of lives within one or more specified indoor or outdoor areas during an emergency. The s.s.e.p. is intended to initiate a rapid and orderly mobilization of occupants in an emergency by including systems using loudspeakers to broadcast voice announcements for emergency purposes, alert signals complying with ISO 7731 (where applicable) and evacuation signals complying with ISO 8201. In some cases, sound systems are used in preference to sounders or bells in order to broadcast a range of coded warnings that is difficult to communicate with sounders or bells. The use of the s.s.e.p. for normal sound reinforcement and distribution systems purposes under non-hazardous circumstances is not excluded. When used for non-emergency purposes, the zoning of the loudspeakers can differ from the zones used for emergency purposes. This part of ISO 7240 does not apply to sound systems that use bells or sounders.