July 12, 2018

Lessons learnt from a refinery fire

  1. A fire started while draining naphtha from a pipeline that ran through a pump house at the refinery.
  2. Investigations revealed that there were three main lapses that led to the fire:

    (a) The refinery had allowed its contractors to drain naphtha from the pipeline by allowing the naphtha to flow out from two open valves and an open flange joint of the pipeline into trays. This open system of de-oiling allowed naphtha vapour to escape into the atmosphere resulting in an accumulation of flammable vapour, which would in turn pose a danger of ignition.

    (b) The refinery had allowed the use of a plastic tray, which was a non-conductive container, as a receptacle for collection of naphtha. The free fall of naphtha onto the plastic tray would allow accumulation of static charges as a result of the friction caused between them. When the accumulated static charges come into contact with any good conductor, they are instantaneously transferred to the conductor. A spark could be caused as a result of the sudden surge of energy during the transfer, which could be sufficient to ignite the naphtha vapour which is within flammable range in the atmosphere.

    (c) The refinery failed to deploy portable gas monitors sufficiently close to the open de-oiling area to give the warning when the build-up of the flammable vapour reached an undesirable level. 
Source: Ministry of Manpower, Singapore

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