Revoked by MSC.188(79)
Resolution
MSC.145(77)
PERFORMANCE STANDARDS FOR WATER LEVEL DETECTORS ON BULK CARRIERS
(adopted
on 5 June 2003)
THE
MARITIME SAFETY COMMITTEE
RECALLING
Article 28(b) of the Convention on the International Maritime Organization
concerning the functions of the Committee,
RECALLING
ALSO that, at its seventy-sixth session, it adopted amendments to chapter XII
of the International Convention for the Safety of Life at Sea (SOLAS), 1974,
inter alia, by introducing new regulation 12 requiring the installation of
water level detectors for hold, ballast and dry spaces,
BEARING
IN MIND that the above-mentioned amendments are expected to enter into force on
1 July 2004 unless, prior to that date, specified conditions with regard to
objections to the amendments are met,
RECOGNIZING
that performance standards against which the operation and efficiency of the
water level detectors can be measured, should be made available in good time
before the above entry-into-force date,
RECOGNIZING
ALSO the need to ensure that the required water level detectors provide
reliable operation and that, to that extent, they are appropriately tested and
installed,
HAVING
CONSIDERED the recommendation made by the Sub-Committee on Ship Design and
Equipment at its forty-sixth session,
1.
ADOPTS the "Performance standards for water level detectors on bulk
carriers" and the appended "Guidelines on installation and testing
for water level detection systems for bulk carriers", as set out in the
Annex to the present resolution;
2.
URGES Governments to ensure that the annexed Performance standards and appended
Guidelines are applied when water level detectors are installed on bulk
carriers flying their flags, in compliance with SOLAS regulation XII/12.
ANNEX.
PERFORMANCE STANDARDS FOR WATER LEVEL DETECTORS ON BULK CARRIERS
This
standard provides technical functional requirements for water level detection
and alarm arrangements installed in bulk carriers for compliance with SOLAS
regulation XII/12.
2.1
Water level detector means a system comprising sensors and indication
devices that detect and warn of water ingress in cargo holds and other spaces
as required in SOLAS regulation XII/12.1.
2.2
Sensor means a unit fitted at the location being monitored that
activates a signal to identify the presence of water at the location.
2.3
Pre-alarm level means the lower level at which the sensor(s) in the
cargo hold space will operate.
2.4
Main alarm level means the higher level at which the sensor(s) in the
cargo hold space will operate or the sole level in spaces other than cargo
holds to which the requirements of SOLAS regulation XII/12 apply.
2.5
Visual indication means indication by activation of a light or other device
that is visible to the human eye in all levels of light or dark at the location
where it is situated.
2.6
Audible indication means an audible signal that is detectable at the
location where it is signalled.
3.1 Means of detecting water level
3.1.1
The method of detecting water level may be by direct or indirect means as
defined below:
.1 A direct means of
detection determines the presence of water by physical contact of the water
with the detection device.
.2 Indirect means of
detection include devices without physical contact with the water.
3.1.2
The sensors should be capable of being located either in the aft part of each
cargo hold or in the lowest part of the spaces other than cargo holds to which
these requirements apply.
3.1.3
The systems of detecting water level should be capable of continuous operation
while the ship is at sea.
3.2 Detector system requirements
3.2.1
Detector systems should provide a reliable indication of water reaching a
preset level.
3.2.2
The system should be capable of the following:
For cargo holds:
.1 An alarm, both visual and
audible, activated when the depth of water at the sensor reaches the pre-alarm
level in the space being monitored. The indication should identify the space.
.2 An alarm, both visual and
audible, activated when the level of water at the sensor reaches the main alarm
level, indicating increasing water level in a cargo hold. The indication should
identify the space and the audible alarm should not be the same as that for the
pre-alarm level.
For compartments other than
cargo holds:
.3 An alarm, both visual and
audible, indicating the presence of water in a compartment other than a cargo
hold when the level of water in the space being monitored reaches the sensor.
The visual and audible characteristics of the alarm indication should be the
same as those for the main alarm level in a hold space.
3.2.3
Detection equipment should be suitably corrosion resistant for all intended
cargoes.
3.2.4
The detector indicating the water level should be capable of activating to an
accuracy of ±100 mm.
3.2.5
The part of the system which has circuitry in the cargo area, should be
intrinsically safe.
3.3.1
The visual and audible alarms should be suitable for location on the navigation
bridge*.
______________
* Reference is made to the requirements of
SOLAS V regulations 17 and 18.
3.3.2
Visual and audible alarms should conform to IMO "Code on Alarms and
Indicators 1995" as applicable to a Primary Alarm for the preservation or
safety of the vessel.
3.3.3
The visual and audible alarms should be capable of the following:
.1 Visual indication using a
light of a distinct colour, or digital display that is clearly visible in all
expected light levels, which does not seriously interfere with other activities
necessary for the safe operation of the ship. The visual indication should be
capable of remaining visible until the condition activating it has returned
below the level of the relevant sensor. The visual indication should not be
capable of being extinguished by the operator.
.2 In conjunction with the
visual indication for the same sensor, the system should be capable of
providing audible indication and alarms in the space in which the indicator is
situated. The audible indication should be capable of being muted by the
operator.
3.3.4
Time delays may be incorporated into the alarm system to prevent spurious
alarms due to sloshing effects associated with ship motions.
3.3.5
The system may be provided with a capability of overriding indication and
alarms for the detection systems installed only in tanks and holds that have
been designed for carriage of water ballast (SOLAS regulation XII/12.1).
3.3.6
An override visual indication capability should be provided throughout
deactivation of the water level detector for the hold or tank referred to in
3.3.5 above. Where such an override capability is provided, cancellation of the
override condition and reactivation of the alarm should automatically occur after
the hold or tank has been deballasted to a level below the lowest alarm
indicator level.
3.3.7
Requirements for malfunctions, alarms and indications should be capable of the
following:
A facility for continuous
monitoring of the system which, on detecting a fault activates a visual and
audible alarm. The audible alarm should be capable of being muted but the
visual indication should remain active until the malfunction is cleared.
3.3.8
The water level detector system should be capable of being supplied with
electrical power from two independent electrical supplies. Failure of the
primary electrical power supply should be indicated by an alarm.
3.4.1
Water level detector systems should be type tested to demonstrate their
robustness and suitability under the appropriate internationally recognized
conditions*.
______________
* With regard to testing, reference is made to
IEC 60092-0504 and the IEC 60529. Electrical components installed in the cargo
holds, ballast tanks and dry spaces should satisfy the requirements of IP68 in
accordance with IEC 60529.
3.4.2
Detectors serving a cargo hold should be capable of being functionally tested
in-situ when the hold is empty using either direct or indirect methods.
3.5.1
Documented operating and maintenance procedures for the water level detection
system should be kept on board and readily accessible.
Guidelines
on installation and testing for water level detection systems for bulk carriers
are set out in the Appendix.
APPENDIX.
GUIDELINES ON INSTALLATION AND TESTING FOR WATER LEVEL DETECTION SYSTEMS FOR
BULK CARRIERS
These
guidelines provide procedures for installation and testing for water level
detection and alarm systems installed in bulk carriers for compliance with
SOLAS regulation XII/12.
2.1 Detector equipment type test requirements
2.1.1
Detector equipment should provide a reliable indication of water reaching a
preset level and should be type tested to demonstrate their robustness and
suitability under the appropriate conditions of IEC 60092-504 and the
following:
.1 Protection of the
enclosures of electrical components installed in the cargo holds, ballast tanks
and dry spaces should satisfy the requirements of IP68 in accordance with IEC
60529. The water pressure testing of the enclosure should be based on a
pressure head held for a period depending on the application. For detectors to
be fitted in holds intended for the carriage of water ballast or ballast tanks
the application head should be the hold or tank depth and the hold period
should be 20 days. For detectors to be fitted in spaces intended to be dry the
application head should be the depth of the space and the hold period should be
24 hours.
.2 Operation in "cargo/water"
mixture for the selected range of cargoes such as iron ore dust, coal dust,
grains and oils using seawater with a suspension of representative fine
material for each cargo. For type test purposes an agitated suspension of
representative fine materials in seawater, with a concentration of 50% by
weight, should be used with the complete detector assembly including any
filtration fitted. The functioning of the detection assembly with any
filtration arrangements should be verified in the "cargo/water"
mixture with immersion repeated ten times without cleaning any filtration
arrangements.
2.1.2
Protection of the enclosures of electrical equipment installed above ballast
and cargo spaces should satisfy the requirements of IP56 in accordance with IEC
60529.
2.2 Detector equipment installation
requirements
2.2.1
The sensors should be located in a protected position that is in communication
with the aft part of the cargo hold such that the position of the sensor
detects the level that is representative of the levels in the actual hold
space. These sensors should be located:
.1 Either as close to the
centre line as practicable, or
.2 At both the port and
starboard sides of the cargo hold.
2.2.2
The detector installation should not inhibit the use of any sounding pipe or
other water level gauging device for cargo holds or other spaces.
2.2.3
Detectors and equipment should be installed where they are accessible for
survey, maintenance and repair.
2.2.4
Any filter element fitted to detectors should be capable of being cleaned
before loading.
2.2.5
Electrical cables and any associated equipment installed in cargo holds should
be protected from damage by cargoes or mechanical handling equipment associated
with bulk carrier operations, such as in tubes of robust construction or in
similar protected locations.
2.2.6
Any changes/modifications to the ship's structure, electrical systems or piping
systems that involves cutting and/or welding should be approved by the
classification society before work is carried out.
3.1.1
Alarm systems should be type tested in accordance with the application of IEC
60092-504 as appropriate.
3.1.2
A switch for testing audible and visual alarms should be provided at the alarm
panel and the switch should return to the "off" position when not
operated.
3.2 Alarm system testing requirement
The
visual and audible alarms are to be tested to demonstrate the following: