Mechanical sensitivity (friction) EC A.14.; UN Series 3, Test 3 (b) (i): BAM friction apparatus
In this test, solid or paste-like substances are subjected to friction between standardized surfaces under specified conditions of load and relative movement.
The friction apparatus consists of a base plate (cast steel) on which the roller assembly, consisting of a fixed porcelain peg and a moving porcelain plate, is mounted. The porcelain plate is fixed in a carriage which runs in two guides. The carriage is connected to an electric motor via a connecting rod, an eccentric cam and suitable gearing such that the porcelain plate is moved, once only, backwards and forwards beneath the porcelain peg a distance of 10 mm. The porcelain peg can be loaded with 120 or 360 N, for example.
The flat porcelain plates are made of pure technical white porcelain (roughness 9 μm to 32 μm) and have the dimensions 25 mm (length) × 25 mm (width) × 5 mm (height). The cylindrical porcelain peg is also made of pure technical white porcelain. It is 15 mm long, has a diameter of 10 mm and a rough spherical end face with a radius of curvature of 10 mm.
The test result is considered positive if an explosion occurs at least once in any of the tests with the specified friction apparatus. Crackling and/or a bang, sparking or flame is equivalent to an explosion. Decomposition (change of color or odor) is not considered an explosion.