Thermal sensitivity EG A.14. UN Series 1/Series 2, Test 1 (b)/Test 2 (b): Koenen test and Series E, Test E.1: Koenen test
For the test, the test substance is heated in a steel tube which is closed by orifice plates with holes of different diameters. This test is used to determine whether the substance is liable to explode under conditions of intense heat and defined confinement.
The apparatus consists of a non-reusable steel tube with its re-usable closing device, installed in a heating and protective device.
Each tube is deep-drawn from sheet steel (see Appendix) and has an internal diameter of 24 mm, a length of 75 mm and wall thickness of 0.5 mm. The tubes are flanged at the open end to enable them to be closed by the orifice plate assembly. This consists of a pressure-resistant orifice plate, with a central hole, secured firmly to a tube using a two-part screw joint (nut and threaded collar). The nut and threaded collar are made from chromium-manganese steel which is spark-free up to 800 °C. The orifice plates are 6 mm thick, made from heat-resistant steel, and are available with holes in a range of diameters.
The test result is considered positive if an explosion occurs at least once in any of the tests with the specified shock apparatus (3 parts).