2 Requirements for public address systems
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.808 – Recommendation on Performance Standards for Public Address Systems on Passenger Ships, Including Cabling – (Adopted on 30 June 1997) - Annex - Recommendation on Performance Standards for Public Address Systems on Passenger Ships, Including Cabling - 2 Requirements for public address systems

2 Requirements for public address systems

  2.1 The public address system should be one complete system consisting of a loudspeaker installation which enables simultaneous broadcast of messages from the navigation bridge, and at least one other location on board for use when the navigation bridge has been rendered unavailable due to the emergency, to all spaces where crew members or passengers, or both are normally present and to assembly stations (i.e. muster stations). The controls of the system on the navigation bridge should be capable of interrupting any broadcast on the system from any other location on board. It should not require any action by the addressee. It should also be possible to address crew accommodation and work spaces separately from passenger spaces.

  2.2 In addition to any function provided for routine use aboard the ship, the system should have an emergency function control at each control station which:

  • .1 is clearly indicated as the emergency function;

  • .2 is protected against unauthorized use;

  • .3 automatically overrides any other input system or programme, and

  • .4 automatically overrides all volume controls and on/off controls so that the required volume for the emergency mode is achieved in all spaces.

  2.3 The system should be installed with regard to acoustically marginal conditions, so that emergency announcements are clearly audible above ambient noise in all spaces where crew members or passengers or both are normally present and to assembly stations (i.e. muster stations). With the ship underway in normal conditions, the minimum sound pressure levels for broadcasting emergency announcements should be:

  • .1 in interior spaces 75 dB(A) and at least 20 dB(A) above the speech interference level; and

  • .2 in exterior spaces 80 dB(A) and at least 15 dB(A) above the speech interference level.

  2.4 The system should be arranged to prevent feedback or other interference.

  2.5 The system should be arranged to minimize the effect of a single failure, e.g. by the use of multiple amplifiers with segregated cable routes. The public address systems should have at least two loops of flame retardant cable which should be sufficiently separated throughout their length and have two separate and independent amplifiers.

  2.6 Each loudspeaker should be individually protected against short circuits.

  2.7 The public address system should be arranged to operate on the main source of electrical power, the emergency source of electrical power and transitional sources of electrical power as required by SOLAS chapter II-1.

  2.8 The space containing a control unit of the public address system is a control station as defined in SOLAS chapter II-2.

Parent topic: Annex - Recommendation on Performance Standards for Public Address Systems on Passenger Ships, Including Cabling
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