*** Circular 1 Results ***
(December 19, 2007)
SDS CG comments to Flooding Detection System Circular 1
(listed and summarized by paragraph)
Guidelines for Flooding Detection Systems on Passenger Ships
Introduction
1
SOLAS regulation II-1/22-1 requires passenger ships, carrying 36 or more
persons constructed on or after 1 July 2010, to be provided with flooding detection
systems for watertight spaces below the bulkhead deck based on guidelines developed by
the Organization.
2
These guidelines are intended to provide detailed requirements for the flooding
detection systems.
Definitions
3
Flooding detection system means a system of sensors and alarms that detect and
warn of water ingress into watertight spaces. Continuous flood level monitoring may be
provided, but is not required.
4
Sensor means a device fitted at the location being monitored that activates a
signal to identify the presence of water at the location.
5
Alarm means an audible and visual signal which announces a flooding condition
requiring attention.
Paragraph 5
CLIA
Perhaps this should refer to the Code on Alarms and Indicators definition: ‘An alarm or
alarm system which announces by audible means, or audible and visual means, a
condition requiring attention.’
Results Summary and Action:
Based on the comment submitted, the Co-ordinators have revised paragraph 5 as
indicated. Please review and comment as necessary.
System Installation
6
A flooding detection system should be fitted in all watertight spaces below the
bulkhead deck that:
1
.1
have a volume in cubic meters (m3) that is more than the ship’s moulded
displacement per centimeter (cm) immersion at deepest subdivision draught; or
.2
have a volume more than 30 m3,
whichever is the greater.
7
Any watertight spaces that are separately equipped with a liquid level monitoring
system (such as fresh water, ballast water, fuel, etc.), with an indicator panel or other
means of monitoring at the navigation bridge (and the safety centre if located in a
separate space from the navigation bridge), are excluded from these requirements.
Paragraph 7
Co-ordinators note: should there be an alarm required for these tanks / indicator panel?
Bahamas
At present, liquid tanks such as fresh water are not necessarily provided with indicators
on the bridge. Under these requirements it is presumed that all liquid tanks as applicable
under paragraph 6 will require some form of level indicator to be installed on the bridge.
The filling level of the tank after damage will vary depending on its location in the ship.
Therefore, fitting an alarm is not considered relevant.
Generally, the most useful information in a casualty situation is the tank filling levels.
This information is necessary in setting up a casualty loading condition to establish the
true state of the damaged vessel.
CLIA
I do not think a separate alarm is necessary – such tanks are in daily use. Overfilling
alarms should be available in the normal operation system. The indication could be a
page on the machinery automation if that is available on the bridge.
Finland
We assume it is not necessary to have a separate alarm in the tanks, which already are
equipped with remote sounding system, with continuous flood level.
France
Indication of level in tanks should be available from the same place as alarms from
flooding detection system of dry spaces.
Germany
They should be excluded.
Italy
The existing tank monitoring system is considered to be already adequate for the purpose.
2
Japan
Japan is of the opinion that there should need a specific performance requirements for the
liquid level monitoring system. For example, an alarm should be activated when the
water level of the tank irregularly rises.
UK
We do not consider it necessary as any flood-water entering these enclosed tank spaces
will be picked up and monitored on the bridge anyway. Also there may be a high-level
alarm already fitted.
Results Summary and Action:
Please review the submitted comments. A majority of the group were of the view that an
alarm is not required for watertight spaces that are separately equipped with a liquid level
monitoring system.
Regarding the navigation bridge indicator panel; although there was general agreement
that liquid level information for these tanks should be available on the navigation bridge,
there were several comments that noted existing liquid level monitoring systems have a
variety of indication methods to accomplish this. Therefore the Co-ordinators have
revised the paragraph to accommodate a variety of possible indication methods. Also to
be consistent with paragraph 11, the availability of this information in the safety centre (if
it is separate from the navigation bridge) has been added. Please review and comment as
necessary.
Sensor Installation
8
The number and location of flooding detection sensors should be sufficient to
ensure that any substantial water ingress into a watertight space requiring a flooding
detection system is detected under reasonable angles of trim and heel. To accomplish
this, flooding detection system sensors required by paragraph 6 should generally be
installed as indicated below:
.1
Vertical location – sensors should be installed as low as practical in the
watertight space but not more than [0.2 m] above the lowest point.
Paragraph 8.3 (note: now moved to 8.1)
Bahamas
The following paragraph is suggested as a way to determine the initial flood volume in a
‘dry’ space. This would allow more freedom on where to locate detectors and allow for
unusual arrangements:
‘Sufficient alarms should be provided such that in no case should it be possible for a
volume of water specified under paragraph 6 to go undetected in a water tight space for
all combinations of heel and trim reflected in complying with the damage stability and
subdivision requirements of this chapter.’
3
CLIA
Minimum installation height above the deck should not exceed 10 cmtr.
Finland
Vertically height within the watertight space of not more than 0.1 m.
Germany
0.5m seems more realistic.
Italy
It should be further noted that the flooding detection system is in addition to bilge level
indicators, i.e. high level alarms fitted to each bilge well. These bilge alarms are provided
via the main monitoring alarm and control system (automation system) of the ship. This
note is relevant also to item 11 below.
Results Summary and Action:
Please review the submitted comments. The response was mixed and reflects the
complexity of developing guidance for the location of flooding detection sensors. Based
on all of the paragraph 8 “sensor location” comments, it seems unlikely we can develop
specific guidance to adequately account for all possible arrangements. Therefore the Coordinators have proposed a new initial “intended purpose” paragraph as well as a new
concluding “special consideration” paragraph in an effort to provide sufficient flexibility
in this regard. Please review and comment as necessary.
Regarding the specific vertical location guidance for flooding detection sensors, the text
has been revised in an effort to accommodate a “middle of the road” group view and
provide some flexibility. Please review and comment as necessary.
Format note: because the vertical location can be the primary factor in locating flooding
detection sensors, the Co-ordinators have moved this item to the first sub-paragraph.
.2
Longitudinal location – in watertight spaces located forward of the midlength, sensors should generally be installed at the forward end of the space; and
in watertight spaces located aft of the mid-length, sensors should generally be
installed at the aft end of the space. For watertight spaces located in the vicinity
of the mid-length, special consideration should be given to the appropriate
longitudinal location of the sensor (which may be at the mid-point of the space).
In addition, any watertight space that is more than [33 m] in length or with
arrangements that would seriously restrict the longitudinal flow of water should
be provided with sensors at both the forward and aft ends.
Paragraph 8.1 (note: now moved to 8.2)
Co-ordinators note: this provision needs to account for excessive trim concerns.
4
Bahamas
The following paragraph is suggested as a way to determine the initial flood volume in a
‘dry’ space. This would allow more freedom on where to locate detectors and allow for
unusual arrangements:
‘Sufficient alarms should be provided such that in no case should it be possible for a
volume of water specified under paragraph 6 to go undetected in a water tight space for
all combinations of heel and trim reflected in complying with the damage stability and
subdivision requirements of this chapter.’
CLIA
Even on a ship of moderate size you are looking at a minimum of 50 sensors. If all
conditions need to be accounted for then this number will more than double with
associated maintenance and cost issues.
Finland
Mainly we propose to install sensors longitudinally in aft part in those watertight spaces
located aftward from midlength (from L/2) and in forward part located forward from L/2.
France
As trim angle is generally much lower than heel angle, one sensor in the middle of each
watertight space should be sufficient.
Germany
Middle of the space.
Italy
An intact ship is normally slightly trimmed aft, but the actual trim / heel in damage
condition is difficult to determine in advance. Some preference is given to a position at
the aft end, but it is anyway recommended to fit the flooding sensors in way of a
bulkhead. A sensor in the middle would be less protected, interfere with the layout and
equipment and the cable routing would be more difficult.
Japan
The flooding detection system should be fitted at the end of the watertight space or the
lowest position of it.
Notwithstanding the above, if the length of the watertight space is more than [33m], the
system should be fitted at both of the forward and aft end of the watertight space.
UK
Ideally sensors should be installed in four corners of each space to ensure at least some
readings where there is excessive heel and/or trim. There are obvious cost implications this number of sensors may be regarded as excessive for spaces of only 30 m3, for
example. On the other hand, having only one sensor for a large public room may not be
adequate in the event of large trim/heel situations. Perhaps we could introduce another
5
criterion on top of 6.1.1 and 6.1.2 - requiring 4 sensors based on space area as a
proportion of total deck area in m2. For example:On any deck below the bulkhead deck, all spaces having an enclosed area of [5%] or
more of the entire enclosed deck area shall be equipped with 4 sensors, one in each
corner.
Results Summary and Action:
Please review the submitted comments. Again, the response was mixed and reflects the
complexity of developing guidance for the location of flooding detection sensors.
In an effort to progress this item given the range of views, the Co-ordinators have revised
the text as indicated. The approach reflects the general view that flooding in the forward
part of the ship will cause forward trim, and flooding in the aft part of the ship will cause
aft trim. In addition, a provision has been included to require two sensors (forward and
aft) whenever a space exceeds a certain length (33 m has been proposed as a starting
point) or has arrangements that would seriously restrict the longitudinal flow of water.
Please review and comment as necessary.
.3
Transverse location – sensors should generally be installed at the
centreline of the space (or alternatively at both the port and starboard sides). In
addition, any watertight space that extends the full breadth of the ship or with
arrangements that would seriously restrict the transverse flow of water should be
provided with sensors at both the port and starboard sides.
Paragraph 8.2 (note: now moved to 8.3)
Co-ordinators note: this provision needs to account for excessive heel concerns.
Bahamas
The following paragraph is suggested as a way to determine the initial flood volume in a
‘dry’ space. This would allow more freedom on where to locate detectors and allow for
unusual arrangements:
‘Sufficient alarms should be provided such that in no case should it be possible for a
volume of water specified under paragraph 6 to go undetected in a water tight space for
all combinations of heel and trim reflected in complying with the damage stability and
subdivision requirements of this chapter.’
CLIA
Even on a ship of moderate size you are looking at a minimum of 50 sensors. If all
conditions need to be accounted for then this number will more than double with
associated maintenance and cost issues.
Finland
In general we prefer to locate sensors on centerline and if sensors will be installed on
6
partial watertight spaces above bulkhead, they should be located both in S- and P-sides.
In special cases depending on the form of the space and flooded water may stay only on
the other side, sensors should be located also port or starboard.
France
For spaces extending over the full breadth of the ship, one sensor on each side would be
necessary to be sure that water will be detected by the sensor. On the other hand, if
sensors are at side, they may be within damage extent and become out of work, so it may
be recommended to have only one sensor at centreline (or at mid breadth of
compartment).
Germany
Centreline, for U-shaped spaces, 2 sensors on each side.
Italy
Preference to centerline - more protected in case of side damage.
Japan
If the watertight space is located at the centerline, the flooding detection system should
be fitted on the centerline, or port and starboard.
If the watertight space is located at the side of the ship, the system should be fitted on
port or starboard, whichever is near the hull plate.
UK
Ideally sensors should be installed in four corners of each space to ensure at least some
readings where there is excessive heel and/or trim. There are obvious cost implications this number of sensors may be regarded as excessive for spaces of only 30 m3, for
example. On the other hand, having only one sensor for a large public room may not be
adequate in the event of large trim/heel situations. Perhaps we could introduce another
criterion on top of 6.1.1 and 6.1.2 - requiring 4 sensors based on space area as a
proportion of total deck area in m2. For example:On any deck below the bulkhead deck, all spaces having an enclosed area of [5%] or
more of the entire enclosed deck area shall be equipped with 4 sensors, one in each
corner.
Results Summary and Action:
Please review the submitted comments. Although the response was mixed, there was a
general view that for a single sensor it should be located transversely at the center of the
space. However there were also several comments that indicated under certain
circumstances, sensors should be located on both the port and starboard sides of the
space. Therefore in an effort to progress this item, the Co-ordinators have revised the
text as indicated. Please review and comment as necessary.
7
However for watertight spaces with unusual arrangements or in other cases where this
guidance would not achieve the intended purpose, the number and location of flooding
detection sensors should be subject to special consideration by the Administration.
9
Where a watertight space extends in height over more than one deck or more than
[3m] or [3.5m], there should be at least one flooding detection sensor at each deck level.
This provision is not applicable in cases where a continuous flood level monitoring
system is installed.
Paragraph 9
CLIA
In case that continuous flood level monitoring sensor are selected there is not needed to
provide multiple unit to detect flooding in space with more then one deck height.
Finland
We support to install sensors in each deck within watertight compartment, if there is no
clear openings below the decks.
If continuous flood level system is installed, then there is no need to install more than one
sensor in one high watertight compartment, for example Main Engine Room.
In other cases sensors in more than 3 m may be necessary.
Germany
Preference: 3.5m.
Italy
Although the principle is agreed and understood, the sentence or more than 3m would
somewhat override the requirement of having the sensors at each deck level (tweendeck
height could be slightly more or less than 3 m). The requirement should be associated
with the possibility of verifying if and when actions are to be taken to prevent
propagation and progressive flooding outside the flooded space, through openings (e.g.
doors) at each deck level, rather than providing an indication of the precise flooded
volume within the space. If deemed necessary, a generic sentence could cover the
possibility of having spaces or deck arrangements of unusual design or height, which
should be left to the satisfaction of the Administration.
Results Summary and Action:
Please review the submitted comments. Although a majority of the group generally
agreed with the draft text, there were several comments regarding the 3m limit (in
relationship to deck height) and a proposal to increase that limit to 3.5m. In addition,
there were also several comments that this provision was not necessary if continuous
flood level monitoring was installed.
Therefore the proposal to increase the fixed height to 3.5m has been added in square
brackets, and a sentence has been added that this provision is not applicable in cases
where a continuous flood level monitoring system is installed. Please review and
comment as necessary. Also please specifically indicate your preference for 3m or 3.5m.
8
10
Where partial watertight bulkheads or divisions are fitted that could impede the
flow of flood water, additional sensors may be necessary.
Alarm Installation
11
Each flooding detection system should give an audible and visual alarm at the
navigation bridge and the safety centre, if located in a separate space from the navigation
bridge. These alarms should indicate which watertight space is flooded.
Paragraph 11
CLIA
Yes. [Safety centre should be included]
“and safety centre if located remote from the bridge.” Code, Table 9.1.2 would require
audible and visual indication in the machinery space/control room.
Finland
Navigation Bridge is continuously manned control station, therefore support to install.
Only flooding detection system on bridge. Not necessary to install on Safety Center.
France
Alarm installation: As an alternative, continuous monitoring sensor may be fitted, linked
to an onboard loading computer. Even in this case, an alarm should be given if water
level is detected.
Italy
If flooding system alarms are provided via the main monitoring alarm and control system
(automation system) of the ship, then the alarms can be acknowledged and monitored
directly, via an already redundant communication network, from each automation system
screen/workstation - normally placed in ECR, wheelhouse, safety centre, and in other
specific locations on board.
Results Summary and Action:
Co-ordinators note: in reviewing new SOLAS regulation II-2/23 - Safety centre on
passenger ships, paragraph 6.16 clearly requires operation / monitoring of the flooding
detection system from the safety centre. This was our mistake for not adequately
researching this item prior to preparing the initial draft guidelines.
Please review the submitted comments. However as indicated in the note above, the
actual provisions of new regulation II-2/23.6.16 resolve this item. The text has also been
modified to more accurately reflect regulation II-2/23.3. Please review and comment as
necessary.
9
12
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.
Paragraph 12
Co-ordinators note: is this provision appropriate?
Bahamas
Reference to the Code on Alarms and Indicators is considered appropriate as it provides
clear guidance on how indicators and alarms should be presented.
CLIA
The Code is ‘recommended’ for alarms and indicators and is intended to provide
guidance to promote uniformity of type, location and priority, etc.
Italy
Conformity to the Code of Alarm and Indicators should be recommended, at least to
provide a common reference standard on the visualization and acknowledgement of the
flooding system alarms. If the flooding monitoring data are conveyed via the ship
automation, then a separate hard-wired system and switches shall not be required.
UK
Not enough known about this Code therefore recommend decision by experts in the field.
Results Summary and Action:
Please review the submitted comments. A majority of the group agreed that reference to
the Code on Alarms and Indicators was appropriate. Therefore no changes seem
necessary. Please review and comment as necessary.
Co-ordinators note: the DE S/C is currently revising the Code on Alarms and Indicators;
it is tentatively scheduled for completion at DE 51 in February 2008.
Design Requirements
13
The flooding detection system and equipment shall be suitably designed to
withstand supply voltage variation and transients, ambient temperature changes,
vibration, humidity, shock, impact and corrosion normally encountered in ships. [Sensor
cabling and junction boxes should be suitably rated to ensure operability of the detection
system in a flooded condition. In addition, the detection system should be designed on
the fail-to-safety principle, where an open sensor circuit should result in an alarm
condition. See the Code on Alarms and Indicators.]
Paragraph 13
CLIA
10
- Detector, cabling, junction boxes should have an adequate IP rating to ensure that the
system function even under flooding.
- Detector control units or data collection units are to be fitted in an un-floodable area
above bulkhead deck. Control network has have the same redundancy of the watertight
doors control system.
- Detectors are to be protected from mechanical damage and be easily accessible and
removable for testing. (see paragraph 15)
- Detector is not to be prone to generate false alarm under normal operating condition, the
type of detector is to be selected accordingly.
Results Summary and Action:
Please review the submitted comments. Based on these comments, the Co-ordinators
have revised paragraph 13 as indicated. Because some of these issues are partially
addressed in the Code on Alarms and Indictors, the Code has been included as a
reference. In addition, the Co-ordinators have added a new sentence to address sensor
circuit failure / damage (which is also addressed in the Code on Alarms and Indictors).
Please review and comment as necessary.
14
The flooding detection system should be continuously powered and should have
an automatic change-over to a stand-by power supply in case of loss of the normal power
supply . Failure of the primary power supply should be indicated by an alarm. See the
Code on Alarms and Indicators.
Paragraph 14
CLIA
Suggest that the second power supply should be from the emergency generator, (and if
computer monitoring, then must have transitional source of power). Code on Alarms and
Indicators (3.6) requires automatic changeover to standby power supply.
Results Summary and Action:
Please review the submitted comments. The text has been revised to more closely align
with the Code on Alarms and Indicators, and to include the Code as a reference. Please
review and comment as necessary.
Detector Maintenance, Accessibility and Testing
[15
Documented operating, maintenance and testing procedures for the flooding
detection system should be kept on board and be readily accessible.
16
Flooding detection system sensors and equipment should be installed where they
are accessible for testing, maintenance and repair.
11
17
The flooding detection system should be capable of being functionally tested
using either direct or indirect methods. Records of testing should be retained on board.]
Paragraph 15
Finland
We support to have clear approved procedure to perform regularly tests to confirm the
proper operating of flooding detection system.
Japan
Japan is of the opinion that the requirements in MSC. Res 188(79) could also be applied
to the flooding detection system required in accordance with these guidelines.
Results Summary and Action:
Please review the submitted comments. There was general support for including
maintenance, accessibility and testing provisions in the guidelines. Therefore the Coordinators have added a new Detector Maintenance, Accessibility and Testing section
with several provisions, which were taken from Resolution MSC.188(79) as suggested.
Please review and comment as necessary.
12