Superseded
by MSC.188(79)/Rev.1
Resolution
MSC.188(79)
PERFORMANCE
STANDARDS FOR WATER LEVEL DETECTORS ON BULK CARRIERS AND SINGLE HOLD CARGO
SHIPS OTHER THAN BULK CARRIERS
(adopted on 3 December 2004)
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, which entered into
force on 1 July 2004,
RECALLING
FURTHER that, at its seventy-ninth session, it approved proposed amendments to
chapter II-1 of the International Convention for the Safety of Life at Sea
(SOLAS), 1974, introducing new regulation 23-3 requiring the installation of
water level detectors on single hold cargo ships other than bulk carriers,
BEARING
IN MIND that the above-mentioned proposed amendments are expected to be adopted
at its eightieth session in May 2005 and to enter into force on a date to be
determined at that session, 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 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 operate
reliably and that, to that extent, they are appropriately tested and installed,
HAVING
CONSIDERED the recommendations made by the Sub-Committee on Ship Design and
Equipment at its forty-sixth and forty-seventh sessions,
1.
ADOPTS the Performance standards for water level detectors on bulk carriers and
single hold cargo ships other than bulk carriers and the appended Guidelines on
installation and testing of water level detection systems for bulk carriers and
single hold cargo ships other than 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 and single hold cargo ships other than bulk carriers flying their
flags, in compliance with SOLAS regulation XII/12 and the afore-mentioned SOLAS
regulation II-1/23-3, as appropriate;
3.
REVOKES resolution MSC.145(77).
PERFORMANCE
STANDARDS FOR WATER LEVEL DETECTORS ON BULK CARRIERS AND SINGLE HOLD CARGO
SHIPS OTHER THAN BULK CARRIERS
These
standards provide technical functional requirements for water level detection
and alarm arrangements installed in bulk carriers for compliance with SOLAS
regulation XII/12 or in single hold cargo ships other than bulk carriers for
compliance with SOLAS regulation II-1/23-3*.
_____________
*Refer to the third, fourth
and fifth preambular paragraphs of the covering MSC resolution.
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 regulations XII/12.1 or II-1/23-3.
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 regulations XII/12 or II-1/23-3 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 the
water level
3.1.1 The method of detecting the
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, in the case of single hold cargo ships complying with
SOLAS regulation II-1/23-3, in the aft part of the hold or above its lowest
point in such ships having an inner bottom not parallel to the designed
waterline, or, in the case of bulk carriers complying with SOLAS regulation
XII/12, in the aft part of each cargo hold or in the lowest part of the spaces
other than cargo holds to which that regulation applies.
3.1.3
The systems of detecting the 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 regulations V/17 and V/18.
3.3.2
Visual and audible alarms should conform to the Code on Alarms and Indicators,
1995, as may be amended, as applicable to a primary alarm for the preservation
or safety of the ship.
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 holds or tanks 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 de-ballasted to a level below the lowest alarm
indicator level.
3.3.7
Requirements for malfunctions, alarms and indications should include 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 60092-504 and IEC 60529. Electrical components
installed in 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.
Documented
operating and maintenance procedures for the water level detection system
should be kept on board and be readily accessible.
Guidelines
on installation and testing of water level detection systems for bulk carriers
and single hold cargo ships other than bulk carriers are set out in the
appendix.
Appendix.
GUIDELINES ON INSTALLATION AND TESTING OF WATER LEVEL DETECTION SYSTEMS FOR
BULK CARRIERS AND SINGLE HOLD CARGO SHIPS OTHER THAN BULK CARRIERS
These
Guidelines provide procedures for installation and testing of water level
detection and alarm systems installed in bulk carriers for compliance with
SOLAS regulation XII/12 and in single hold cargo ships other than bulk carriers
for compliance with SOLAS regulation II-1/23-3*.
________________
*Refer to the third, fourth
and fifth preambular paragraphs of the covering MSC resolution.
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 h.
.2 Operation in
cargo/water mixture for a selected range of cargo groups such as iron ore dust,
coal dust, grains and oils using seawater with a suspension of representative
fine material for each cargo group. 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 specified part of the cargo hold (usually the aft part) 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 centreline 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