The First 40 FT Freight Container in Europe Qualified as an IP-2/IP-3 and Type a Package

Abstract

The first successful free fall drop test with a 40 ft ISO freight container in Europe (as far as we know also in the world) took place in Bremen (Germany) at the dry dock of the former Vulkan ship yard on 25 September 1998. This drop test was performed to qualify the ISO Boxcontainer as an IP-2/IP-3 and Type A package in accordance with IAEA Regulations Safety Series No 6 (1985 edition, as amended 1990) and the new IAEA Safety Standards Series No ST-1 (1996 Edition). The freight container has successfully passed the whole sequence of required tests to demonstrate compliance with Type A requirements (free drop test, stacking test, penetration test and, instead of the water spray test, the more stringent pressure and bubble test was performed) of the IAEA Regulations. This paper concentrates on the free fall drop test because this is the most difficult of the required Type A tests which needs to be passed. Further, the free fall drop test is required to qualify a freight container in accordance with the alternative requirements for industrial packages IP-2,3 (new ST-1, § 627), the requirements for industrial packages (new and old IAEA Regulations) and Type A requirements. Therefore, the freight container was qualified as IP-2,3 and Type A package performing a free fall drop test. The overall dimensions of the so called LONGFORCE® container are: length 12192 mm (40 ft); width 2438 mm (8 ft); height 2491 mm (8 ft 6 in). The 40 ft ISO freight container prototype was fully loaded with 28 t of steel plates together with shock absorbing material to simulate the load and load securing system. The total drop test weight was 35·6 t. In accordance with IAEA Regulations Safety Series No 6 and ST-1, the LONGFORCE® container was dropped onto an unyielding foundation in a position which suffered the maximum damage in respect of the package safety features. The package was dropped on its corner, door side down on the roof, with the centre of gravity over the impact area (slap-down drop). The container was lifted 12·6 m high (highest point) respectively 0·3 m (lowest point) under a drop angle of 70°. The combined mass of the concrete block and the steel plate (impact pad) was way above 100 times that of the container test specimen. The first impact resulted in an acceleration of about 100 g where the maximum was near the impact. The second impact, in general, yielded far higher acceleration values in the vertical direction of 160 up to 200 g. A third impact was recorded which turned out to be decisive, showing maximum acceleration readings in the range of about 200 up to 250 g. The container was inspected after the drop test and deformations of the container rear corner castings (area second impact) and a small weld crack in one of the corner castings welds was found. On the container floor one third of transverse support beams showed Sform distortion. The LONGFORCE container was leak tested prior to and after the drop test in compliance with the STM (STM stands for Safety Technology Management GmbH, owner of the container design and rights and sponsor of the drop test work) leak test procedure. The leak tests consisted of filling the container with pressurised air up to 5 kPa and recording a possible pressure drop over a determined test period. The container was considered leak tight prior to and after the drop test based on the permissible limits set in the leak test procedure. The free fall drop test is considered a full success qualifying the 40 ft LONGFORCE container as an IP-2/IP-3 Type A package in compliance with the IAEA SS No 6 and also with the new IAEA ST-1 regulations.