Around 5:30 p.m., a fire broke out on an injection moulding machine located in a 700 m² facility of a company specialising in the manufacture of polystyrene packaging. The fire brigade made a hole in the upper part of the building to contain the fire. The emergency services attended to 14 people. The polystyrene drying silo and the moulding press were destroyed.
According to the operator’s analysis, the fire was caused by the presence of pentane near the press, at a concentration greater than the LEL (Lower Explosive Limit). The ignition source appears to be the failure of the electrical protection for the press’ control box. Pentane is normally present since it is this gas, enclosed in the polystyrene, which enables polystyrene beads to expand as the temperature rises.
The operator took the following preventive measures:
- troubleshooting of the control box;
- installation of a pentane detection system above the machines installed below the silos;
- installation of a cabinet outside the plant with a vest and plant map;
- review of the alarm’s trigger time once smoke is detected.
Other short-term actions were planned:
- redesign of the explosive zoning (ATEX) by an inspection organisation and the appropriateness of the electrical and non-electrical equipment;
- an explosion risk study conducted by an inspection body;
- IR thermographic control on the electrical installations (cabinets and cable trays) near high-risk areas;
- review of the workshop and floor cleaning methods and instructions;
- discussion on water suppression to avoid splashing towards electrical cabinets, a source of short circuits;
In the longer term, the operator plans to separate flammable materials from the production areas by removing silos and grouping them in a specific location. The operator’s analysis revealed the need to better protect installations against a pentane build-up in the workshop and to thoroughly inspect the installation’s restart conditions following a repair or maintenance phase.
