MSC/Circ.808
(adopted on 30 June 1997)
RECOMMENDATION ON PERFORMANCE STANDARDS FOR PUBLIC ADDRESS SYSTEMS
ON PASSENGER SHIPS, INCLUDING CABLING
1 The Maritime Safety Committee, at its
sixty-eighth session (28 May to 6 June 1997), noted that the 1995 SOLAS
Conference, in adopting amendments to the 1974 SOLAS Convention concerning the
safety of ro-ro passenger ships, adopted Conference resolution 7 - Development
of requirements, guidelines and performance standards, whereby the Committee
was re quested to develop relevant requirements, guidelines and performance
standards to assist in the implementation of the amendments adopted by the
Conference.
2 The Committee, having considered
recommendations made by the Sub-Committee on Ship Design and Equipment (DE), at
its fortieth session, approved the Recommendation on performance standards for
public address systems on passenger ships, including cabling, set out in the
annex.
3 Member Governments are invited to
bring the annexed Recommendation to the attention of those concerned and use
the provisions contained therein, as appropriate, in conjunction with the
relevant requirements of the 1974 SOLAS Convention, as amended.
ANNEX
Recommendation on Performance Standards for Public Address Systems
on Passenger Ships, Including Cabling
1 Application
These
performance standards should apply to public address systems required by SOLAS
regulation III/6.5.
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.