These performance standards should apply to public address systems required by
SOLAS regulation III/6.5.
Requirements for public address systems
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.
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.
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
.1 in interior spaces 75 dB(A) and at least 20 dB(A) above the speech interference
.2 in exterior spaces 80 dB(A) and at least 15 dB(A) above the speech interference
The system should be arranged to prevent feedback or other interference.
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.
Each loudspeaker should be individually protected against short circuits.
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.
The space containing a control unit of the public address system is a control station as
defined in SOLAS chapter II-2.
Cabling for public address and alarm systems
Cables and wiring serving internal communications or signals should, as far as
practicable, be routed clear of galleys, laundries, machinery spaces of category A and
their casings and other high fire risk areas unless serving those spaces. Where practicable,
all such cables should be run in such a manner so as to preclude their being rendered
unserviceable by heating of the bulkheads that may be caused by a fire in an adjacent
space. All areas of each fire zone should be served by at least two dedicated loops
sufficiently separated throughout their length and supplied by independent amplifiers.
Equipment associated with the public address systems should meet the requirements for
a vibration and electromagnetic interference in the current edition of publication 533 or
publication 945 of IEC, as appropriate. Electrically powered systems should provide a
minimum degree of ingress protection appropriate to the location, in accordance with IEC
Relevant sections of the Code on Alarms and Indicators should also be applied.