A new wood fibre drying system is being built in one of the plants producing construction materials (e.g. thermal insulation and structural materials).
In order to indicate the hazards resulting from the presence of dust explosive atmospheres, the ATEX experts were tasked with the preparation of the Explosion Risk Assessment and determination of explosion hazard zones The tubular dryer in question is located in an open space, adjacent to the older drying installation.
The works on the document were preceded by a site visit and provision of the required information and materials by the Client.
The drying process will be used to produce wood fibre – its dust can generate an explosive atmosphere. In this case, the main parameters which should be taken into consideration are minimum flashpoint of the dust cloud and layer – the drying temperature should always be lower than these values.
The dryer includes a gas burner, indirectly heating the drying air. The burner is supplied with natural gas from the network. Due to the very low minimum ignition energy MIE for methane (i.e. below 1 mJ), there is a significant risk of ignition, event with electrostatic discharges. Furthermore, the high value of the Pmax parameter, both for the wood fibre and the natural gas results in very serious potential consequences of the explosion of any of these substances.