Merchant Shipping (Safe Containers Convention) Act, 2011 (Act No. 10 of 2011)Annex II : Structural Safety Requirements and Tests |
Introduction
In setting the requirements of this Annex, it is implicit that in all phases of the operation of containers the forces as a result of motion, location, stacking and weight of the loaded container and external forces will not exceed the design strength of the container. In particular, the following assumptions have been made:
| a) | the container will so be restrained that it is not subjected to forces in excess of those for which it has been designed; |
| b) | the container will have its cargo stowed in accordance with the recommended practices of the trade so that the cargo does not impose upon the container forces in excess of those for which it has been designed. |
Construction
| 1. | A container made from any suitable material which satisfactorily performs the following tests without sustaining any permanent deformation or abnormality which would render it incapable of being used for its designed purpose shall be considered safe. |
| 2. | The dimensions, positioning and associated tolerances of corner fittings shall be checked having regard to the lifting and securing systems in which they will function. |
Test loads and test procedures
Where appropriate to the design of the container, the following test loads and test procedures shall be applied to all kinds of containers under test:
1. Lifting
The container, having the prescribed internal loading, shall be 1ifted in such a way that no significant acceleration forces are applied. After lifting, the container shall be suspended or supported for five minutes and then lowered to the ground.
(A) Lifting from corner fittings
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
A uniformly distributed load such that the combined weight of container and test load is equal to 2 R. In the case of a tank-container, when the test weight of the internal load plus the tare weight is less than 2 R, a supplementary load distributed over the length of the tank is to be applied to the container. |
(i) Lifting from top corner fittings:
Containers greater than 3 000 mm(10 ft) (nominal) in length shall have lifting forces applied vertically at all four top comer fittings. Containers of 3 000 mm (10ft) (nominal) in length or less shall have lifting forces applied at all four top comer fillings, in such a way that the angle between each lifting device and the vertical shall be 30°. |
Externally applied forces:
Such as to lift the combined weight of 2 R in the manner prescribed (under the applied in such a manner that the lifting heading TEST PROCEDURES). |
(ii) Lifting from bottom corner fittings:
Containers shall have lifting forces devices bear on the bottom comer fittings only. The lifting forces shall be applied at angles to the horizontal of: 30° for containers of length 12 000 mm (40ft) (nominal) or greater, 37' for containers of length 9 000 mm (30 ft) (nominal) and up to but not including 12 000 mm ( 40 ft) (nominal), 45' for containers of length 6 000 mm (20 ft) (nominal) and up to but not including 9 000 mm (30ft) (nominal), 60' for containers of less than 6 000 mm (20 ft) (nominal). |
(B) Lifting by any other additional methods
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
A uniformly distributed load such that the combined weight of container and test load is equal to 1,25 R. In the case of a tank-container, when the test weight of the internal load plus the tare weight is less than 1,25 R, a supplementary load distributed over the length of the tank is to be applied to the container. |
(i) Lifting from fork-lift pockets:
The container shall be placed on bars which are in the same horizontal plane, one bar centred within each fork-lift pocket which is used for lifting the loaded container. The bars shall be of the same width as the forks intended to be used in the handling, and shall project into the fork pocket 75% of the length of the fork pocket. |
Externally applied forces:
Such as to lift the combined weight of 1,25 R in the manner prescribed (under the same the heading TEST PROCEDURES). |
(ii) Lifting from grappler arm positions:
The container shall be placed on pads in horizontal plane, one under each grappler arm position. These pads shall be of the same sizes as the lifting area of the grappler arms intended to be used. |
(iii) Other methods:
Where containers are designed to be lifted in the loaded condition by any method not mentioned in (A) or (B)(i) and (ii) they shall also be tested with the internal loading and externally applied forces representative of the acceleration conditions appropriate to that method. |
2. Stacking
| 2.1 | For conditions of international transport where the maximum vertical acceleration forces vary significantly from 1,8 g and when the container is reliably and effectively limited to such conditions of transport, the stacking load may be varied by the appropriate ratio of acceleration forces. |
| 2.2 | On successful completion of this test the container may be rated for the allowable superimposed static stacking weight, which should be indicated on the Safety Approval Plate against the heading ALLOWABLE STACKING WEIGHT FOR 1,8 g (kg and lb). |
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
A uniformly distributed load such that the combined weight of container and test load is equal to 1,8 R. Tank-containers may be tested in the tare condition.
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The container, having the prescribed internal loading, shall be placed on four level pads which are in turn supported on a rigid horizontal surface, one under each bottom comer titling or equivalent corner structure. The pads shall be centralized under the fittings and shall be of approximately the same plan dimensions as the fittings. |
Externally applied forces:
Such as to subject each of the four top corner fittings to a vertical downward force equal to 0.25 x I ,8 x the allowable superimposed static stacking weight. |
Each externally applied force shall be applied to each of the corner fittings through a corresponding test corner fitting or through a pad of the same plan dimensions. The test corner fitting or pad shall be offset with respect to the top corner fitting of the container by 25 mm (1 in) laterally and 38 mm (1½ in) longitudinally. |
3. Concentrated Loads
Test Loadings and Applied Forces |
Test Procedures |
(a) On roof |
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Internal loading:
None. |
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Externally applied forces:
A concentrated load of 300 kg (660 lb) uniformly distributed over an area of 600 mm x 300 mm (24 in x12 in). |
The externally applied forces shall be applied vertically downwards to the outer surface of the weakest area of the roof of the container. |
Test Loadings and Applied Forces |
Test Procedures |
(b) On floor |
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Internal loading:
Two concentrated loads, each of 2 730 kg (6 000 lb) and each applied to the container floor through a contact area of 142 cm2 (22 sq in). |
The test should be made with the container resting on four level supports under its four bottom corners in such a manner that the base structure of the container is free to deflect.
A testing device loaded to a weight of 5 460 kg (12 000 lb), that is 2 730 kg (6 000 lb) on each of two surfaces, having, when loaded, a total contact area of 284 cm² (44 sq in), that is 142 cm² (22 sq in) on each surface, the surface width being 180 mm (7 in) spaced 760 mm (30 in) apart, centre to centre, should be manoeuvred over the entire floor area of the container. |
Externally applied forces:
None. |
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4. Transverse Racking
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
None. |
The container in tare condition shall be placed on four level supports, one under each bottom comer, and shall be restrained against lateral and vertical movement by means of anchor devices so arranged that the lateral restraint is provided only at the bottom comers diagonally opposite to those at which the forces are applied. |
Externally applied forces:
Such as to rack the end structures of the container sideways. The forces shall be equal to those for which the container was designed. |
The externally applied forces shall be applied either separately or simultaneously to each of the top corner fittings on one side of the container in lines parallel both to the base and to the planes of the ends of the container. The forces shall be applied first towards and then away from the top comer fittings. In the case of containers in which each end is symmetrical about its own vertical centerline, one side only need be tested, but both sides of containers with asymmetric ends shall be rested. |
5. Longitudinal Restraint (Static Test)
When designing and constructing containers, it must be borne in mind that containers, when carried by inland modes of transport, may sustain accelerations of 2 g applied horizontally in a longitudinal direction.
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
A uniformly distributed load, such that the combined weight of a container and test load is equal to the maximum operating gross weight or rating, R. In the case of a tank-container, when the weight of the internal load plus the tare is less than the maximum gross weight or rating, R, a supplementary load is to be applied to the container. |
The container, having the prescribed internal loading, shall be restrained longitudinally by securing the two bottom comer fittings or equivalent comer structures at one end to suitable anchor points. |
Externally applied forces:
Such as to subject each side of the container to longitudinal compressive and tensile forces of magnitude R, that is, a combined force of 2 R on the base of the container as a whole. |
The externally applied forces shall be applied first towards and then away from the anchor points. Each side of the container shall be tested |
6. End-Walls
The end-walls should be capable of withstanding a load of not less than 0,4 times the maximum permissible payload. If, however, the end-walls are designed to withstand a load of less or greater than 0,4 times the maximum permissible payload, such a strength factor shall be indicated on the Safety Approval Plate in accordance with Annex I, Regulation I.
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
Such as to subject the inside of an end- wall to a uniformly distributed load of 0,4 P or such other load for which the container may be designed. |
The prescribed internal loading shall be applied as follows: Both ends of a container shall be tested except that where the ends are identical only one end need be tested. The end-walls of containers which do not have open sides or side doors may be tested separately or simultaneously. The end-walls of containers which do have open sides or side doors should be tested separately. When the ends are tested separately the reactions to the forces applied to the end-wall shall be confined to the base structure of the container. |
Externally applied forces:
None. |
7. Side-Walls
The side-walls should be capable of withstanding a load of not less than 0,6 times the maximum permissible payload. If, however, the side-walls are designed to withstand a load of less or greater than 0,6 times the maximum permissible payload, such a strength factor shall be indicated on the Safety Approval Plate in accordance with Annex I, Regulation I.
Test Loadings and Applied Forces |
Test Procedures |
Internal loading:
Such as to subject the inside of a side- wall to a uniformly distributed load of 0,6 P or such other load for which the container may be designed. |
The prescribed internal loading shall be applied as follows: Both sides of a container shall be tested except that where the sides are identical only one side need be tested. Side-walls shall be tested separately and the reactions to the internal loading shall be confined to the comer fittings or equivalent comer structures. Open-topped containers shall be tested in the condition in which they are designed to be operated, for example, with removable top members in position. |
Externally applied forces:
None. |