4.1.1 Crew
and embarked personnel address systems are to comply with the International
Lifesaving-Saving Appliances (LSA) Code and the requirements
of this Section.
4.1.2 The
crew and embarked personnel address system is to be provided with
an emergency source of electrical power as required by Vol 2, Pt 9, Ch 2, 5.2 Emergency source of electrical power and also connected to the
main source of electrical power with automatic changeover facilities
located adjacent to the crew and embarked personnel address system.
Failure of any power supply is to operate an audible and visual alarm, see also
Vol 2, Pt 9, Ch 3, 8.10 Cable support systems 8.10.6 and Vol 2, Pt 9, Ch 1, 5.2 Centralised control station for machinery.
4.1.3 The
crew and embarked personnel address system is to have multiple amplifiers
having their power supplies so arranged that a single fault, fire
or casualty will not cause the loss of the facility to broadcast emergency
announcements in crew and embarked personnel rooms, alleyways, stairways
and control stations, albeit at a reduced capacity.
4.1.4 The
crew and embarked personnel address distribution system is to be so
arranged that a fire or casualty in any one main vertical zone, other
than the zone in which the crew and embarked personnel address control
station is located, will not interfere with the facility to broadcast
emergency announcements in any other such zone, see also
Vol 2, Pt 9, Ch 1, 2.6 Operation under flooding conditions.
4.1.5 There
are to be at least two cable routes in each fire zone sufficiently
separated throughout their length to crew and embarked personnel rooms,
alleyways, stairways, and control stations so arranged that any single
electrical fault, localised fire or casualty will not cause the loss
of the facility to broadcast emergency announcements in any crew and
embarked personnel rooms, alleyways, stairways, and control stations,
albeit at a reduced capacity.
4.1.6 Amplifiers
are to be continuously rated for the maximum power that they are required
to deliver into the system for audio and, where alarms are to be sounded
through the crew and embarked personnel address system, for tone signals.
4.1.7 Loudspeakers
are to be continuously rated for their proportionate share of amplifier
output and protected against short-circuits.
4.1.8 Amplifiers
and loudspeakers are to be selected and arranged to prevent feedback
and other interference. There are also to be means to automatically
override any volume controls, so as to ensure the specified sound
pressure levels are met.
4.1.9 Where
the crew and embarked personnel address system is used for sounding
the general emergency alarm and the fire-alarm, the following requirements
are to be met in addition to those of Vol 2, Pt 9, Ch 10, 5.1 Emergency alarm system:
-
The emergency
system is given automatic priority over any other system input.
-
More than one
device is provided for generating the sound signals for the emergency
alarms.
4.1.10 Where
more than one alarm is to be sounded through the crew and embarked
personnel address system, they are to have recognisably different
characteristics and additionally be arranged, so that any single electrical
failure which prevents the sounding of any one alarm will not affect
the sounding of the remaining alarms.
4.1.11 The
sound pressure levels are to be measured during a practical test using
speech and, where applicable, tone signals and documented, see
Vol 2, Pt 9, Ch 12, 1.2 Trials
4.1.12 Sound
signal equipment, fire and general alarm bells are to be supplemented
by visual indications, in areas having high levels of background noise,
such as machinery spaces.