Explosion proofing
April 1st 2008

One tiny spark from a switch or the heat present on the surface of a forklift truck motor could cause an explosion in many UK warehouses. Pyroban works extensively with the materials handling industry to help prevent major industrial accidents in warehouses where flammable material is handled and stored

The materials handling industry supplies a broad range of customers who store flammable materials. If there is a release of flammable gas, vapour or powder, it is quite possible that unless the materials handling equipment used in the area is suitably protected, it could be the source of an ignition. For example, hot surfaces or arcing and sparking components found on a forklift truck can ignite a gas, vapour or powder cloud.

Such risks are present in industries such as paints and coatings, inks and resins, chemicals, bottled gas and aerosols, pharmaceutical, cosmetics and foods and flavours including the many distilleries.

However, some of the biggest risks in warehouses now exist within the 3rd party logistics sector as the industries listed above seek to outsource elements of their business.

Zone 2 warehouses Since DSEAR* came into force, a company has to undertake several duties including risk assessments to determine whether areas on site should be classified as hazardous or potentially explosive. When areas are classified as either Zone 1, 2, 21 or 22, the risk management process is clear, and companies should select equipment that is compliant with the European ATEX 94/9/EC Directive.

Darren Boiling, Pyroban's Customer Service Manager in the South of England explains "By definition, a warehouse containing flammable gases or liquids in sealed containers (i.e a drum or IBC) will usually be classified as Zone 2 depending on the quantity of the hazard and various other factors such as ventilation." All types of warehouse products such as VNAs, order pickers, pallet trucks, reach and forklift trucks can be ordered from the manufacturers or their dealers fully compliant with ATEX 94/9/EC, although once delivered it becomes the user's responsibility for it to be correctly serviced by engineers trained to work on explosion proof systems. An annual EX-ASA audit of each machine helps the user to ensure the equipment stays explosion proof and ATEX compliant throughout its lifetime.

'Safe' warehouses where flammable material is present Darren Boiling continues "But what happens if the user's risk assessment does not lead to hazardous area classification even though they are handling flammable material? The risk of explosion surely cannot be ruled out? This situation does occur and safety conscious companies particularly in the 3rd party logistics and warehousing sector chose to operate their standard equipment with an additional safety system known as Gascheka." Added safety is achieved by companies operating fleets of new or existing equipment, including LPG powered vehicles, through fitting Gascheka that integrates into the equipment to be operated. Normally fitted in one day, the safety system will only enable equipment to operate if the operating area is free of flammable gas or vapour. If gas or vapour is detected then the operator receives audible and visual warning alarms and the equipment will automatically shutdown at 25% of the Lower Explosive Limit (Propane in Air).

By virtue of the automatic shutdown all arcing and sparking components are isolated from the explosive atmosphere until the area is deemed safe by "the person in authority". The protected equipment can only then be restarted by the "person in authority" master key.

Gascheka includes critical features that help maintain safety on a daily basis including automatic calibration of the gas sensing system through a simple automatic forced-gas test before the equipment can be started. This ensures that operators know that it is working correctly. The use of Gascheka also helps a user to follow some of the explosion prevention measures of the ATEX "workers" directive supporting a process that requires the worker (in this case the equipment operator) to be withdrawn before the explosive atmosphere was present.

Responsibility for improving the safety of workers in the warehouse includes appropriate training for those workers in the event of an incident or emergency evacuation. Areas that could contain potentially explosive atmospheres must also be clearly marked and the areas made known to not just the company's employees but also contractors and anyone visiting site. Equipment delivered to site explosion proof must be maintained explosion proof by experienced and competent personnel.

The risk of explosion can be managed effectively provided that a company carries out its risk assessment under DSEAR properly and then manages the risk effectively. For further information, visit www.pyroban.com

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