PA SYSTEM

Public Address System

Public Address System

Introduction

The PA system shall be divided into one or more zones (up to a maximum of 8 zones) which can be accessed independently for announcement or alarm broadcasts. Zones can be designated as to function, such as: “work areas” or “accommodations”. Physically, loudspeakers or beacon circuits shall support zones where one or more circuits can be partitioned into a zone. Each loudspeaker or beacon circuit shall be connected to the central equipment for amplification and control/monitor functions. Paging announcements shall be broadcast through loudspeakers installed in the various areas and locations throughout the facility. The system shall allow calls between it and any existing public address system. The system shall be modular in design and shall be easily expandable.

The area coverage will be such that calls will be clearly audible in the paged operating areas and their surrounding space. Final distribution of loudspeakers over the zones will be determined during detailed design. Each zone shall be split into loops, where each loop is physically connected to a different amplifier. This configuration ensures that a loss of a single amplifier does not adversely affect paging broadcasts within a zone. The distribution of loudspeakers will be related to area configuration and other operational objectives. Cable distribution throughout the plant area will be designed such that all loops relevant to the same zone are laid up separately following different paths, in order to ensure that cable cuts or shorts will cause a minimum effect on the zone broadcast.

Suitable speech amplifiers shall drive the loudspeaker lines. The system shall provide facilities for automatic insertion of a hot standby amplifier(s) in the event of a single/multiple amplifier failure. Access panels shall support operator voice announcement and alarm control operations. Announcements are classified as “routine” or “emergency”, where an emergency announcement shall take precedence over all other audio broadcasts. The system shall be expandable to provide inputs for up to 16 fully fitted microphone panels. Announcements shall be pre-configured to broadcast in designated zones. A zone selection feature shall enable users to direct routine announcements to selected zones. Alarm operations shall initiate the broadcast of alarm tones or pre-recorded messages to pre-configured designated zones. Access panels shall be connected to the central equipment and accorded an access priority for announcements. Alarms shall be accorded a broadcast priority that gives the most critical alarm precedence. Each access panel shall be able to:

Address a call to one or multiple zones. (maximum 8)

Address a call to one or multiple groups of zones, by activating the selected groups of zones.

Transmit a general call to the whole area activating all zones simultaneously. The speech messages shall be announced by an automatically generated preannouncement attention signal.

Discussion and Analysis

The access panels shall be interlocked to prevent interference on the call in progress for the same zone or group of zones from lower priority panels. In addition, all audio signals to be broadcast shall be able to be configured with different levels of priority in order to allow ...