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ANNEX 1
RESULTS OF THE INVESTIGATION BY THE ICS OF THE RECORDS OF ACCIDENTS RELATED TO DANGEROUS GOODS ON CONTAINER SHIPS WITH PARTIALLY WEATHERPROOF HATCHWAY COVERS
Identification of hazards due to the stowage of freight containers containing dangerous goods on container ships with partially weather-proof hatchway covers
| 1 |
All replies received from shipping lines showed that: |
| .1 |
shipping lines with experience with these vessels (together
moving more than 200,000 TEU containing dangerous goods per year) have had no
incidents in regard of leakage which was considered to be different due to the
gap;
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| .2 |
a shipping line with no experience with these vessels commented
that no different situation would have occurred in any of the leakage incidents
on ships fitted with partially weather-proof hatchway covers; and
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| .3 |
a shipping line with 12 years experience with open top vessels
(stowing a lot of containers containing dangerous goods on the outer row, next
to and partly above the open hold) reported to have had no incidents where a spill
got into the open hold. |
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Information on spillages and possible consequences
| 2 |
Not too much feedback on spills was received (see also 1),
but following leakages can occur. |
| .1 |
normal leakage (Jerrycan, drum or IBC (30,300 litter or 3,000
litters)) will never result in serious spillage through the gap; and
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| .2 |
the maximum leakage occurs when a tank-container collapses.
Even than the spill will be minimal. |
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Reference for 2.1
A freight container with leakage inside will result in the spilled cargo (contents of one packaging only) to drip out of the freight container, through the floor or at the door side.
| Re: |
worst case scenario, an IBC with 3000 liter:
We cannot imagine the reason why this should burst open in a freight container
(normal leak occurs due a leaking valve or a small hole due to e.g. a nail) but
even if it would happen the spill would leak out of the freight container over
a period of 15 minutes to several hours or even days. |
|
Reference for 2.2
No shipping line has experienced an incident of a collapse of tank container ON DECK (with or without dangerous goods) during a normal sea voyage. If such a collapse occur ON DECK, spilled goods would probably enter into the hold but vessel staff would notice this right away.
Note : Prevention of spill:
| .1 |
Information on the decision of SLF Sub-Committee in respect
of ingress of water
SLF 44/4/1 Annex 2 2.6 mentions
Labyrinths, gutterbars or equivalents should be fitted proximate to the edges
of each panel. In way of the gaps to minimize the amount of water that can enter
the container hold from the top surface of each panel. |
| .2 |
Ventilation in holds prevents also, partly, (due to air pressure)
the ingress of a liquid but even more of a gas. |
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Answers to the questionnaire
| Companies 1: |
All certified as "weathertight". |
| Companies 2: |
No vessels with such a design. |
| Companies 3: |
No vessels with such a design. |
| Companies 4: |
Watertight and weathertight but not partially weathertight. |
| Companies 5: |
Does not see what the issue is, none of their incidents would
have had a different outcome in case the hatch covers had not been weathertight. |
| Companies 6: |
15 vessels of which two new built and the oldest 9 years old.
Size between 2,500 and 5,000 TEU. No incidents mentioned. |
| Companies 7: |
42 vessels of which the oldest 6 years old. Size between 2,000
and 6,500 TEU. No incidents mentioned. |
| Companies 8: |
Operates these vessels as of 1992. They include 7 hatch-cover-less
vessels in 1993 approx. 6,000 - 9,000 TEU. DG were shipped on these type of vessels
in year 2000 approx. 60,000 - 80,000 TEU. No incidents in relation to the partially
weather-proof hatchway covers. |
| Companies 9: |
43 vessels of which the oldest 3 years old. (most vessels 2001)
Size between 5,000 and 6,200 TEU. No incidents. |
ANNEX 2
POSSIBLE PRINCIPLES FOR STOWAGE AND SEGREGATION OF FREIGHT CONTAINERS CONTAINING DANGEROUS GOODS ON SHIPS WITH PARTIALLY WEATHER-PROOF HATCHWAY COVERS
Special requirements for "on-deck" stowage, taking into account the significant possibility of entering of dangerous goods into cargo holds in case of leakage
| 1 |
Freight containers containing dangerous goods should not be
stowed in the vertical lines specified with ["X", "A", "B" and "C"] in figures
1 and 2, on cargo holds fitted with partially weather-proof hatchway covers unless
the cargo hold complies with the relevant requirements for the class and flash
point of the dangerous goods in SOLAS regulation II-2/19 and with the special
provisions adopted by the Organization on fire protection for such cargo holds. |
| Note 1 : |
ICS was of the opinion that only "X" should be left and "A",
"B" and "C" should be deleted when gutterbars exist. |
| Note 2 : |
Japan was of the opinion that "C" should be deleted and "X",
"A" and "B" should be considered by the working group at DSC 7. |
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Special requirements for segregation of freight containers, taking into account the significant possibility of entering of dangerous goods into cargo holds in case of leakage and possibility of propagation of fire through the clear gaps
| 2 |
Freight containers containing incompatible dangerous goods
should not be stowed in sensitive vertical lines under deck ("D" in figures 1
& 2) in the same bay of the reference freight container in case where the reference
freight container is stowed on relevant hatchway covers ("X", "A" and "B" in figures
1 & 2) and "not in the same vertical line unless segregated by a deck" is required. |
Athwartship
Fig. 1 Definitions of vertical lines
Athwartship
Fig. 2 Definitions of vertical lines
| Note : |
"X", "A" and "D" are the "sensitive vertical lines". |
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ANNEX 3
DISCUSSION POINTS FOR DETERMINING THE APPLICATION OF THE POSSIBLE PRINCIPLES
| 1 |
The positions of freight containers should be categorized,
based on vertical lines, in relation to the position of clear gaps. For the categorization,
the group was of the opinion that figures 1 and 2 in annex 2 could be used. |
| 2 |
The possibility of entry of dangerous goods into a cargo hold
in case of leakage from freight containers stowed in vertical lines "X", "A",
"B" and "C" should be evaluated in relation to the height of gutterbars. The maximum
width of clear gaps should also be specified, e.g., 50 mm, for the purpose of
the clarification of the words "partially weather-proof hatchway covers", as necessary. |
| Note : |
The group considered that it was not useful to discuss the
maximum width of clear gaps, because the width of clear gap was uncontrollable
but it would never be extraordinary value in practice. |
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| 3 |
If the possibility of entry of dangerous goods into a cargo
hold in case of leakage is "insignificant/negligible" under a certain condition,
e.g., the height of gutterbars is not less than 25 mm, any special requirements
is not necessary for the stowage and segregation of freight containers containing
dangerous goods in the relevant vertical lines. |
| 4 |
If the possibility of entry of dangerous goods into a cargo
hold in case of leakage is "significant", e.g., when no gutter-bars or labyrinth
structure is available or when the reference container is stowed in the vertical
line marked with "X", special requirements should be applied for stowage and segregation
of freight containers containing dangerous goods in the relevant vertical lines. |
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