In a pyrotechnic plant, combustion with high thermal radiation occurred in an oven (a chamber dedicated to storing pyrotechnic products at a temperature above ambient temperature) containing 2 kg of infrared bars (used in the composition of infrared cartridges).

As part of the company’s experimental activities, an ageing test (known as a “climatic test”) was being performed in the oven. The purpose of this test was to recreate the natural ageing of the infrared bars over a theoretical period of one year and at a temperature of 65 °C. By placing the products in conditions where the temperature exceeds 80 °C, the products can be aged by one year over a period of just 101 days. A spontaneous combustion phenomenon of the infrared bars, which led to the combustion phenomenon, occurred after just 51 days of testing.

The effects were fully contained in the housing in question. The door and control panel of the oven were damaged. The combustion phenomenon observed, with high thermal radiation, is in keeping with the expected behaviour for this type of product.

Following the accident, the operator decided to:

• reinforce the validation process for test requests;
• conduct ageing tests in an oven and a dedicated area on an indoor target butt;
• install firewalls between ovens.

An accident involving compositions being studied, stored in an oven, had occurred at this company in 2015 (ARIA 47146).