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.Before being tested for resistance to detonation, thewhole mass of the sample is to be thermally cycled five timesbetween 25°C and 50°C (Âą 1°C) in sealed tubes.The sample shallbe maintained at the extreme temperatures, measured at the centreof the sample, for at least 1 hour during each thermal cycle andat 20°C (Âą 3°C) after complete cycling until tested.5.3 MaterialsSeamless steel tube to ISO 65-1981-Heavy or equivalentTube length 1000 mmNominal external diameter 114 mmNominal wall thickness 5 to 6.5 mmBottom plate (160 x 160 mm) of good weldable quality, thickness 5to 6 mm to be butt welded to one end of the tube around theentire circumference.Initiation system and boosterElectrical blasting cap or detonating cord with non-metallicsleeve (10 to 13 g/m).Compressed pellet of secondary explosive, such as hexogen/wax95/5 or tetryl, with a central recess to take the detonator.500 Âą 1 gramme plastic explosive containing 83 to 86 % penthrite,formed into a cylinder in a cardboard or plastic tube.Detonation velocity 7300 to 7700 m/s.Six witness cylinders of refined, cast lead for detectingdetonation50 mm diameter x 100 mm high, refined lead of at least 99.5%purity.5.4 ProcedureTest Temperature: 15 to 20°C.Figures 1 and 2 show the testarrangement.Fill the tube about one-third of its height with the test sampleand drop it 10 cm vertically five times on the floor.Improvethe compression by striking the side wall with a hammer betweendrops.A further addition shall be made such that, aftercompaction or by raising and dropping the tube 20 times and atotal of 20 intermittent hammer blows, the charge fills the tubeto a distance of 70 mm from its orifice.Insert the plastic explosive into the tube and press it down witha wooden die.Place the compressed pallet centrally in therecess within the plastic explosive.Close it with a wooden discso that it remains in contact with the test sample.Lay the testtube horizontally on the 6 lead cylinders placed at 150 mmintervals (centric), with the centre of the last cylinder 75 mmfrom the bottom plate, on a firm, level, solid surface that isresistant to deformation or displacement.Insert the electricalblasting cap or the detonating cord.Ensure that all necessary safety precautions are taken, connectand detonate the explosive.Record, for each of the lead cylinders, the degree of compressionexpressed as a percentage of the original height of 100 mm.Foroblique compression, the deformation is taken as the average ofthe maximum and minimum deformation.5.5 ResultsThe test is to be carried out twice.If in each test one or moreof the supporting lead cylinders are crushed by less than 5%, thesample is deemed to satisfy the resistance to detonationrequirements.Figure 1: Booster chargeFigure 2: Positioning of the steel tube on the firing siteResponsible DNV Section: MTPNO876Document ID: SB04A0205BA2004 Code of Safe Practice for Solid Bulk Cargoes (BC Code)5 Description of the Test of Resistance to Detonation5 Description of the Test of Resistance to Detonation5.1 Principle5.1.1 The test sample is confined in a steel tube andsubjected to detonation shock from an explosive booster charge.Propagation of the detonation is determined from the degree ofcompression of lead cylinders on which the tube restshorizontally during the test.5.2 Sample Preparation5.2.1 The test must be carried out on a representative sampleof cargo.Before being tested for resistance to detonation, thewhole mass of the sample is to be thermally cycled five timesbetween 25°C and 50°C (Âą 1°C) in sealed tubes.The sample shallbe maintained at the extreme temperatures, measured at the centreof the sample, for at least 1 hour during each thermal cycle andat 20°C (Âą 3°C) after complete cycling until tested.5.3 MaterialsSeamless steel tube to ISO 65-1981-Heavy or equivalentTube length 1000 mmNominal external diameter 114 mmNominal wall thickness 5 to 6.5 mmBottom plate (160 x 160 mm) of good weldable quality, thickness 5to 6 mm to be butt welded to one end of the tube around theentire circumference.Initiation system and boosterElectrical blasting cap or detonating cord with non-metallicsleeve (10 to 13 g/m).Compressed pellet of secondary explosive, such as hexogen/wax95/5 or tetryl, with a central recess to take the detonator.500 Âą 1 gramme plastic explosive containing 83 to 86 % penthrite,formed into a cylinder in a cardboard or plastic tube.Detonation velocity 7300 to 7700 m/s.Six witness cylinders of refined, cast lead for detectingdetonation50 mm diameter x 100 mm high, refined lead of at least 99.5%purity.5.4 ProcedureTest Temperature: 15 to 20°C.Figures 1 and 2 show the testarrangement.Fill the tube about one-third of its height with the test sampleand drop it 10 cm vertically five times on the floor.Improvethe compression by striking the side wall with a hammer betweendrops.A further addition shall be made such that, aftercompaction or by raising and dropping the tube 20 times and atotal of 20 intermittent hammer blows, the charge fills the tubeto a distance of 70 mm from its orifice.Insert the plastic explosive into the tube and press it down witha wooden die.Place the compressed pallet centrally in therecess within the plastic explosive.Close it with a wooden discso that it remains in contact with the test sample.Lay the testtube horizontally on the 6 lead cylinders placed at 150 mmintervals (centric), with the centre of the last cylinder 75 mmfrom the bottom plate, on a firm, level, solid surface that isresistant to deformation or displacement.Insert the electricalblasting cap or the detonating cord.Ensure that all necessary safety precautions are taken, connectand detonate the explosive.Record, for each of the lead cylinders, the degree of compressionexpressed as a percentage of the original height of 100 mm.Foroblique compression, the deformation is taken as the average ofthe maximum and minimum deformation.5.5 ResultsThe test is to be carried out twice [ Pobierz całość w formacie PDF ]
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