This test is designed to determine the lowest temperature at which, under insulated conditions, a substance shows an exothermic reaction. The test set consists of:

- Electrically heated, thermostatically controlled oven

- Dewar flask (sensitivity of test increases with increasing volume.

- Cylindrical containers of stainless steel wire mesh

- Temperature control and recording system Sipcon

- Thermocouples, protected by thin glass tubes

Heat Accumulation in the Dewar flask:

The testing for thermal stability is carried out under almost adiabatic conditions (the energy generated by the exothermic decomposition is not removed). Therefore, self-heating of the substance occurs, which accelerates the decomposition. The decomposition reaction is excited to the maximum heat generation. In case of a sufficiently high temperature increase, which is independent of the total energy of decomposition, there may be a thermal explosion.

Hot Storage in the Wire Mesh Basket:

A so-called hot storage test can be used to assess the dangers which may exist in handling larger product quantities. The products to be tested are filled into cylindrical wire mesh baskets which are stored in an air-purged oven (2 l/min) at constant temperature.

The test in the wire mesh container must be carried out on products which are to be dried in a fluid bed. It can also be applied to products which are to be dried in a recirculating air oven.

Swiss Institute for the Promotion of Safety and Security

Adrien Bisel, Phone +41 (0)61 696 55 99, Fax +41 (0)61 696 70 72

Petra Meier, Phone +41 (0)61 696 57 24, Fax +41 (0)61 696 70 72