ABSTRACT
Outline the fire hazards, risks and controls relating to hydrocarbons.
Learning outcome
Lightning
Fire triangle and potential consequences of explosions and thermal radiation
Electrostatic charges
The identification of ignition sources
Zoning/hazardous area classification and selection of suitable ignition-protected electrical and mechanical equipment and critical control equipment
Key revision points
Threats from a lightning strike include:
Sparks which can cause a fire or explosion Power surges to electrical equipment, particularly monitoring and
safety devices, which can render them inoperable
Protection from lightning strikes is a specialist area requiring expert knowledge as to what systems are suitable for each facility. In general, the necessary precautions are:
Keep the lightning channelled far away from the immediate neighbourhood of flammable and explosive materials Avoid sparking or flashover in joints and clamps, and at nearby
components Prevent the overheating of conductors Prevent flashover or sparking due to induced voltages Prevent raising the potential of the earth termination system All metal containers to be of sufficient thickness (usually 5 mm
minimum) Down-conductors to be fitted to all other metal structures and in
sufficient numbers as to subdivide any current surge adequately All earthing systems to be interconnected to a single earth
termination system. This usually takes the form of a mesh or grid pattern around the site.
