Ingangsdatum: 06-11-1991
Geldig tot en met: 30-06-1996
General
3.1 The presentation of alarms and indicators should be
clear, unambiguous, and consistent.
3.2 All required alarms should be indicated by both
audible and visual means, except the emergency alarms of 2.2 which
should be indicated primarily by audible alarms. In machinery spaces
with high ambient noise level, audible alarms should be supplemented by
visual alarms in accordance with 5.1. Audible alarms may also be
supplemented by visual alarms in accommodation spaces.
3.3 A new alarm condition should be clearly
distinguishable from those existing and accepted, e.g., existing and
accepted alarms are indicated by a constant light and new alarms are
indicated by a flashing light. At control positions or other suitable
positions as required, alarm systems should
clearly
distinguish between normal, alarm, and accepted alarm conditions.
3.4 Alarms should be maintained until they are accepted
and the visual indications of individual alarms should remain until the
fault has been corrected, when the alarm system should automatically
reset to the normal operating condition. If an alarm has been accepted
and a second fault occurs before the first is rectified, the audible and
visual alarms are to operate again.
3.5 Alarms should only be capable of being cancelled if
the condition causing them has been dealt with successfully.
3.6 Required alarm systems should be continuously
powered and should have an automatic change-over to a stand-by power
supply in case of loss of normal power supply. Emergency alarms and
primary alarms should be powered from the main source of electrical
power and from emergency source of electrical power defined by SOLAS
regulations 11-1/42 or 11-1/43 unless other arrangements are permitted
by those regulations, as applicable, except that:
- the power-operated sliding watertight door closure alarm power
sources may be those used to close the doors;
- the fire-extinguishing medium alarm power source may be the medium
itself; and
- continuously charged, dedicated accumulator batteries of an
arrangement, location, and endurance equivalent to that of the
emergency source of electrical power may be used instead of the
emergency source.
3.7 Required rudder angle indicators and power-operated
sliding watertight door position indicators should be powered from the
main source of electrical power and should have an automatic change-over
to the emergency source of electrical power in case of loss of normal
power supply.
3.8 Failure of the normal power supply of required alarm
systems should be indicated by an audible and visual alarm.
3.9 Required alarm systems should, as far as is
practicable, be designed on the fail-to-safety principle, e.g., an open
detection circuit should cause an audible and visual alarm; see also
SOLAS regulations 11-2/13.1.2 and 11-1/51.1.4.
3.10 Provision should be made for functionally testing
required alarms and indicators. The Administration should ensure, e.g.,
by training and drills, that the crew is familiar with all emergency and
primary alarms.
3.11 Required alarms and indicator systems should be
functionally independent of control systems and equipment, or should
achieve equivalent redundancy. Any additional requirements for
particular alarms in the IMO instruments applicable to the ship should
be complied with.
3.12 Computer programs for computerized alarm and
indicator systems should not be permanently lost or altered as a result
of power supply loss or fluctuation. Provision should be made to prevent
unintentional or unauthorized alteration of computer programs.
3.13 Cables for emergency alarms and their power sources
should be of a fire-resistant type and be run as directly as is
considered practicable by the Administration. Equipment and cables for
emergency alarms should be arranged to minimize risk of total loss of
service due to localized fire, collision, flooding or similar
damage.
3.14 To the extent considered practicable by the
Administration, emergency alarms should be arranged so that the audible
alarm signal can be heard regardless of failure of anyone circuit or
component.
3.15 Means should be provided to prevent normal
operating conditions from causing false alarms, e.g., provision of time
delays because of normal transients.
3.16 Alarms and indicators on the navigating bridge are
to be minimized. Alarms and indicators which are not required alarms and
indicators for the navigating bridge should not be placed on the
navigating bridge, unless permitted by the Administration.
3.17 The system should be arranged so that all alarm
signals can be accepted or cancelled at the appropriate control position
only.
3.18 In order to facilitate maintenance and reduce risk
of fire or harm to personnel, consideration should be given to providing
means of isolation of sensors fitted to tanks and piping systems for
flammable fluids or fluids at high temperature or pressure (e.g. valves,
cocks, pockets for temperature sensors).