23 July 1997
This hazard alert is issued following a fire in a laboratory in the Pharmacology Department late in 1996. The fire occurred in the early hours of the morning. The laboratory was unoccupied and consequently there were no injuries. However, there was significant damage to the laboratory and to instruments and equipment within the laboratory. Although considerable time has elapsed since the fire, the laboratory is still out of service due to the effects of the fire.
A circulating heater coil (Julabo Brand Paratherm 77) had been placed in a water-filled plastic bucket in a fume cupboard. The heater was inadvertently left switched on overnight. Eventually, the water in the bucket evaporated and the bucket and the plastic fume cupboard shell caught fire. The fire was automatically detected by the thermal detectors in the laboratory ceiling and the fire brigade arrived and extinguished the fire before it spread to any other rooms. The heater-stirrer unit was not fitted with either an over temperature or low flow cut-out switch. Investigations after the fire revealed similar equipment in use in nearby laboratories with polystyrene foam being used to cover the tops of the vessels that contained the liquid being heated. The foam was apparently being used in an attempt to stop evaporation. The foam covering did not achieve this aim and in the process, it also obscured from view the level of the liquid in the vessels.
The following recommendations are intended as preventive measures and should be implemented, where applicable, by all laboratory departments.
All new heater/stirrer devices are to be purchased with cutout switches which will provide over-temperature and low-flow protection.
Refer also to the Hazard alert overheating of ovens and other heating devices issued by OHS on 11 March 1997. This alert makes recommendations that relate specifically "Live Unattended Equipment".
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