IMSML Website Article 53/2024: Resolution MSC.188(79)/Rev.2 - Revised Performance Standards for Water Level Detectors on Ships Subject to SOLAS Regulations II-1/25, II-1/25-1 and XII/12
This Resolution is applicable in Malaysia via Malaysian Shipping Notice (MSN) 12/2023, and is the 17th subject-matter in Annex 1. There are revised performance standards in Paragraph 17.1 for water level detectors in:
[1] Vessels (other than bulk carriers) which have a single cargo hold (see SOLAS II-1/25);
[2] Ships with multiple cargo holds (other than bulk carriers and tankers)(see SOLAS II-1/25-1);
[3] Bulk carriers (in compliance with SOLAS XII/12) adopted via Resolution MSC.482(103).
ANNEX 26, SEE MSC.107/20/ADD.1
Section 1 - PURPOSE
Not only are bulk carriers covered (see SOLAS Regulation XII/12), but the performance standards also apply to:
[1] Single hold cargo ships other than bulk carrier (see SOLAS Regulation II-1/25); AND …
[2] Multiple cargo hold ships other than bulk carriers and tankers (see SOLAS Regulation II-1/25-1).
The technical standards provide functional requirements for bilge alarms used as water level detectors in multiple hold cargo ships (see SOLAS Regulation II-1/25-1).
Section 2 - DEFINITIONS
The definitions cover ‘water level detector’ (see Section 2.1) to ‘Sensor’ (see Section 2.2), from ‘pre-alarm level’ (see Section 2.3) to ‘main alarm level’ (see Section 2.4), as well as ‘visual indication’ (see Section 2.5) to ‘audible indication’ (see Section 2.6).
Section 3 - FUNCTIONAL REQUIREMENTS
Section 3.1 - Means of Detecting the Water Level
Section 3.1.1 provides for two means of detecting water level:
[1] Direct means - Determines the presence of water by physical contact between the detection device and the water (see Section 3.1.1.1);
[2] Indirect means - Using a device that does not need physical contact with the water (see Section 3.1.1.2).
Where should sensors be located? See Section 3.1.2 which provides:
[1] At the aft part of the or above its lowest points in such ships having an inner bottom not parallel to the designed waterline; OR …
[2] In case of bulk carriers complying with SOLAS Regulations 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.
Should the systems of detecting the water level be capable of continuous operation while the ship is at sea? YES !!! (See Section 3.1.3)
Section 3.2 - Detector System Requirements
Should detector system provide a reliable indication of water reaching a preset level? YES, see Section 3.2.1.
The capabilities of systems are divided into the following by Section 3.2.2:
[1] Cargo holds:
[a] Alarm (visual and audible) that when activated by the depth of water reaching the pre-alarm level in the space being monitored. The indication should identify the space (see Section 3.2.2.1);
[b] Both a visual and audible alarm, that activates when the depth of water reaches the main alarm level, indicating increasing water level in a cargo hold. The indication should identify the space. The visual and audible alarm should not be the same as that for the pre-alarm level in a hold space (see Section 3.2.2.2).
[2] Compartments other than cargo holds (see Section 3.2.2.3):
[a] This requires both a visual and audible alarm that indicates the presence of water in a compartment other than a cargo hold.
[b] This occurs when the level of water in the space being monitored reaches the sensor;
[c] The visual and audible characteristics of the alarm indication should be the same as those for the main alarm level in a hold space.
Should detection equipment be suitably corrosion resistant for all intended cargo spaces? YES, see Section 3.2.3.
What should the level of accuracy of a detector that indicates water level? It should be capable to activating to a level of accuracy of +/- 100mm, see Section 3.2.4.
Should the detection equipment be certified safe and appropriate for the intended cargoes? YES, see Section 3.2.5.
Section 3.3 - Alarm System Requirements
What location is suitable for visual and audible alarms? It should be on suitable locations on the navigations bridge, see Section 3.3.1.
As a primary alarm for the preservations of safety of the ship, what is the benchmark standard for visual and audible alarms? The Code on Alerts and Indicators 2009 (as may be amended), see Section 3.3.2.
What should the visual and audible alarms be capable of? Section 3.3.3 provides for the following:
[1] Visual indication (see Section 3.3.3.1):
[a] Usage of a light of a distinct colour;
[b] Clearly visible digital display (Note, this should not interfere with other activities necessary for the safe operation of the ship);
[c] Capable of remaining visible until the conditions activating it has returned below the level of the relevant sensor;
[d] Not capable of being extinguished by the operator.
[2] Audible indication (see Section 3.3.3.2):
[a] Capable of providing audible indication and alarms in the space in which the indicator is situated;
[b] Capable of being muted by the operator.
Can time delays be incorporated into the alarm system to prevent spurious Alams due to sloshing effects associated with ship motions? YES, see Section 3.3.4.
When water level are used in cargo holds or tanks which be used for water ballast, could an alarm overriding device be installed? YES, see SOLAS Regulations II-1/25-1 and XII/12.1.
Throughout the deactivation of the water level detector for such holds or tanks, should an override visual indication capability be provided? YES, see Section 3.3.5.
Should cancellations of the override conditions and reactivation of the alarm occur automatically after the hold or tank has been de-ballasted to a level below the lowest alarm level indicator? YES, see Section 3.3.5.
What should happened when a fault is detected? Alarms and indications should include a facility for continuous monitoring which activates a visual and audible alarm when a fault is detected, see Section 3.3.6.
Could the audible alarm be muted? Yes, but the visual indication should remain active until the malfunction is cleared, see Section 3.3.6.
Does a water level detector need to be supplied with electrical power from two independent electrical supplies? YES, see Section 3.3.7. (Note, if any of the two electrical power supply fails, this should be indicated by an alarm).
Section 3.4 - Testing
Should water level detector systems be tested to demonstrated their robustness and suitability under the appropriately international recognised conditions and for their continued functioning under the expected service temperature? YES, see Section 3.4.1.
Should detectors serving a cargo hold should be capable of being functionally tested, in situ? Yes, this should be done when the hold is empty using either direct or indirect methods, see Section 3.4.2.
Section 3.5 - Manuals
Is there a requirement for documented on operations and maintenance of the water level detection system be kept on board and be readily accessible? Yes, Section 3.5.
Section 4 - INSTALLATION AND TESTING
What is the benchmark / guidelines for installation and testing of water level detection systems for ships? See SOLAS Regulations II-1/25, II-1/25-1 and XII/12.
Section 5 - BILGE ALARMS USED AS WATER LEVEL DETECTORS
General rule - bilge alarms may be used as water level detectors, provided they meet the functional requirements, installation and testing requirements, see Section 5.1.
Exceptions:
[1] Some cargoes require the bilge pumping system to be protected to prevent the spread of contaminated or potentially dangerous fluids, see Section 5.2;
[2] The bilge well can be completely sealed when specific cargoes are carried, ie it cannot be used for the entry of ingress water to the detector(s). Therefore, a suitable detection point or points should be provided, see Section 5.3;
Section 6 - PERIODIC TESTING
How often should water level detectors be tested? Periodically, to the same extent as specified in Section 3.3. The records should be retained on board.
Appendix, see Annex 26, P 7
This part contains the ‘Guidelines on Installations and Testing of Water Level Detection Systems on Ships Subject to SOLAS Regulations II-1/25, II-1/25-1 and XII/12’.
The Guidelines deal with:
[1] Detector equipment type, test and installation requirements;
[2] Alarm system requirements and its testing requirements;
[3] A list of manuals that should be kept on board.
Thank you for reading IMSML Website Article 53/2024
Stay tuned for the next IMSML Website Article 54/2024: Resolution MSC.548(107) - International Code of Safety for Diving Operations 2023 (2023 Diving Code)
Signing-off for today,
Dr Irwin Ooi Ui Joo, LL.B(Hons.)(Glamorgan); LL.M (Cardiff); Ph.D (Cardiff); CMILT
Professor of Maritime and Transport Law
Head of the Centre for Advocacy and Dispute Resolution
Faculty of Law
Universiti Teknologi MARA Shah Alam
Selangor, Malaysia
Tuesday, 22 October 2024
Note that I am the corresponding author for the IMSML Website Articles. My official email address is: uijoo310@uitm.edu.my