IMO AMENDMENTS TO THE CSS CODE

Transcription

1 INTERNATIONAL MARITIME ORGANIZATION E IMO SUB-COMMITTEE ON DANGEROUS GOODS, SOLID CARGOES AND CONTAINERS 11th session Agenda item 10 7 July 2006 Original: ENGLISH AMENDMENTS TO THE CSS CODE Proposal on revising the Guidelines for securing arrangements for the transport of road vehicles on ro-ro ships (resolution A.581(14)) Submitted by Sweden SUMMARY Executive summary: This document contains a proposed amendment to Appendix 4 Guidelines for securing arrangements for the transport of road vehicles on ro-ro ships (resolution A.581(14)) - of the CSS Code Action to be taken: Paragraph 15 Related documents: DSC 10/7; DSC 10/17, paragraphs 7.2 and 7.3; and the CSS Code Introduction 1 Sweden proposed in document DSC 10/7 to amend item 6.1 in Appendix 4 of the CSS Code as follows: 6.1 The maximum securing load (MSL) of lashings should not be less than 100 kn, and they should be made of material having suitable elongation characteristics The number and the maximum securing load (MSL) of lashings should be sufficient to prevent road vehicles from shifting. The lashing material should have suitable elongation characteristics. By this proposed amendment to Appendix 4 of the CSS Code it would be possible for the operator to secure road vehicles, on ro-ro ships, with a suitable number of lashings and a combined strength depending on the requirements for the actual weight of the vehicle and the particulars of the ship. Securing vehicles in the lower part of the concerned weight interval or on ferries on short voyages in restricted areas with lashings not less than MSL of 100 kn is not feasible and does not increase the level of safety. For reasons of economy, this document is printed in a limited number. Delegates are kindly asked to bring their copies to meetings and not to request additional copies.

2 - 2 - Background 2 The Sub-Committee agreed that the proposal of Sweden, as elucidated in document DSC 10/7, had merit and, noting that by agreeing to the amendment in isolation might have repercussions on other parts of the CSS Code, invited Sweden to submit a revised proposal for consideration at DSC According to the guidelines in resolution A.581(14), which is included in the CSS Code as Appendix 4, all Road Vehicles with a total mass of between 3.5 and 40 tonnes on board ro-ro ships should be secured by lashings having a maximum securing load (MSL) not less than 100 kn. This is typically accomplished by 13 mm class 8 chains. In resolution A.581(14) the number of lashings to be used is not stipulated, however, less than two lashings per side is usually not practicable. 4 Annex 13 of the CSS Code includes methods to assess the efficiency of securing arrangements for non-standardized cargo. One method to be used is the following Rule-of-thumb method as stated in paragraph 5: The total of the MSL values of the securing devices on each side of a unit of cargo (port as well as starboard) should equal the weight of the unit. 5 The two different guidelines mentioned above can result in cargo units having to be secured with different MSL depending on if it is Road Vehicles or non-standardized cargoes, even if the units have the same characteristics, is transported on the same ship at the same location and is exposed to the same accelerations. In the lower weight interval Road Vehicles must be secured with larger MSL, while in the upper weight interval Road Vehicles may be secured with lesser MSL than non-standardized cargo. This can result in ro-ro ships on international voyages, which secure cargo according to an approved Cargo Securing Manual, being judged differently during port state controls MSL [kn] 200 According to Res A.581(14), using two lashings per side 100 According to Annex 13 of the CSS Code Cargo Weight [tonnes] Figure 1. Total MSL for each side of vehicle as a function of the cargo weight. 6 Sweden has, for some time, successfully applied the method to design securing systems according to Annex 13 of the CSS Code also for Road Vehicles. To eliminate problems that may occur for ships on international voyages, it is proposed that the Code is modified according to paragraph 1 of this proposal.

3 - 3 - Investigation of requirement on lashing strength in the CSS Code 7 The requirement on the securing systems for different types of cargoes mentioned in the CSS Code have been investigated, and in no other part of the CSS Code than in appendix 4, the exact strength of the lashings is specified. Although the required strength of the lashings is expressed differently in different sections in the Code, no conflict would arise from implementing the modification proposed in paragraph 1 above. All sections of the Code containing recommendations for lashing strength have been studied, in accordance with the wish expressed by the Sub-Committee at DSC 10, and are compiled below: - Paragraph General about forces: Forces which have to be absorbed by suitable arrangements for stowage and securing to prevent shifting are generally composed of components acting relative to the axes of the ship: longitudinal, transverse and vertical. - Paragraph General about criteria to be considered: When considering the risk of cargo shifting among others the following should be considered: Dimensional and physical properties of the cargo Suitability of the ship for the particular cargo - Paragraph General about criteria to be considered: These criteria should be taken into account when selecting suitable stowage and securing methods and whenever reviewing the forces to be absorbed by the securing arrangements. - Paragraph General about cargo securing arrangements:., the arrangement should be verified by using an acceptable calculation method. - Annex 1 - Containers, paragraph 2.1: All containers should be effectively secured in such a way as to protect them from sliding and tipping. - Annex 1 - Containers, paragraph 2.3: Lashings should preferably consist of wire ropes or chains or material with equivalent strength and elongation characteristics. - Annex 2 - Portable tanks, paragraph 6.1.1: The securing devices on non-standardized portable tanks and on the ship should be arranged in such a way as to withstand the transverse and longitudinal forces, which may give rise to sliding and tipping. - Annex 4 wheel-based (rolling) cargoes except Road Vehicles, paragraph 2.6: Wheel-based cargoes should be secured to the ship by lashings made of material having strength and elongation characteristics at least equivalent to steel chain or wire. - Annex 5 Heavy Cargo Items, paragraph 5.2: The securing devices should be arranged in such a way as to withstand the transverse and longitudinal forces which may give rise to sliding and tipping. - Annex 5 Heavy Cargo Items, paragraph 11.1: Where necessary, the securing arrangement for heavy cargo items should be verified by an appropriate calculation in accordance with annex 13 to the Code.

4 - 4 - Proposal - Annex 6 Steel Coils, paragraph 3.3: Conventional lashings should consist of wires having sufficient tensile strength. - Annex 7 Heavy Metal Products, paragraph 4.3: the top layer of each stow should be secured by lashings of adequate strength - Annex 13 Calculation Method, paragraph 2.1: The annex 13 method should provide guidance for the preparation of the Cargo Securing Manual and the examples therein. - Annex 13 Calculation Method, paragraphs 7.2.1, and 7.2.3: The balance calculation for transverse sliding, transverse tipping and longitudinal sliding should meet. - Appendix 2 MSC/Circ.745, annex, paragraph 3.2.3: The Cargo Securing Manual should contain examples of how to calculate number and strength of portable securing devices to counteract the forces as well as safety factors to be used for different types of portable cargo securing devices. Calculations may be carried out according to annex 13 to the CSS Code or methods accepted by the Administration. 8 In the light of the above investigation, Sweden proposes that securing systems also for Road Vehicles on ro-ro ships should be designed according to the same principles as for all other types of wheel-based (rolling) cargoes. The securing system should thus be verified by the calculation methods in annex 13 to the Code and the number and strength of the lashings should be sufficient to prevent sliding and tipping of the Road Vehicles. 9 The proposed modification will result in a possibility for the operator to secure Road Vehicles with the same type and same number of lashings as a function of the cargo weight as other types of wheel-based cargoes. 10 According to paragraph 6.7 of resolution A.581(14), it is for the master to decide the number of securing points and lashings to be used for each voyage, therefore the level of safety will not be impaired by the proposed modification but kept at the same level. In addition to that, all ships engaged in the carriage of all cargoes other than solid and liquid bulk cargoes is required to have a Cargo Securing Manual approved by the Administration. Example calculation 11 A wheel-based unit with a total mass of 3.5 tonnes should be secured with a total MSL of 4.5 tonnes on each side of the unit, according to the Rule-of-thumb in Annex 13. This requires two web lashings each with MSL 2.25 tonnes, approximately 22 kn, on each side of the vehicle. 12 A Road Vehicle with the same weight, following the guidelines in resolution A.581(14), the MSL of lashings should not be less than 100 kn, e.g. one 13 mm class 8 chains on each side. Most units require lashings both in the front as well as in the rear. If this is necessary, the vehicle needs to be secured with two lashings on each side, which results in a total MSL of 200 kn on each side of the vehicle. Compared to the Rule-of-thumb, this ends up with almost 5 times the total MSL of lashings for the cargo.

5 Below two photos are shown of a vehicle with a total gross vehicle mass (GVM) of about 4.5 tonnes secured by four lashing with a MSL of 100 and 25 kn respectively. From the photos it is obvious that the requirement is not practicable that road vehicles with a mass of 4.5 tonnes on ro-ro ships should be secured by lashings having a MSL of minimum 100 kn. Vehicle weighing 4.5 tonnes secured by chain lashings with MSL=100 kn Vehicle weighing 4.5 tonnes secured by web lashings with MSL=25 kn Conclusion 14 The proposed modification will result in a possibility to achieve the required level of safety in different ways without changing the actual required safety standard. It will be possible for the operator to secure a vehicle with a higher number of lashings, each with a lower MSL, where this is the most practical solution. The same level of safety will be guaranteed by the Cargo Securing Manual. Action requested of the Sub-Committee 15 The Sub-Committee is invited to consider the above proposal and to take action as appropriate.