Situation:
Natural gas is used as fuel for a burner unit in a powder
flash drying process within a building. This gas pipework has flanges, joints,
electricals, fittings, etc.
Task:
To minimise the potential for the formation of flammable atmospheres (external and internal within the burner unit)
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Typical Natural gas pipework feeding into a burner unit |
Action (Solution):
Within the burner unit
An appropriate burner management system should have the following:
- Should shut off the fuel supply on flame failure and on loss of combustion air.
- Should incorporate an air purge sequence, which ensures that any residual flammable gas is purged from the burner unit before it is relit.
External to the burner unit:
The following can be undertaken:
- Provide
ventilation to the area. This could be achieved by forced (mechanical) or natural
ventilation by installing louvres or other openings in a manner to provide
a cross flow of air over the equipment, where leaks may occur.
- Install
a gas detection system. Detectors could be installed to identify a leak of
flammable materials, and alert users to the leak. This system could be
linked to a means of isolating heating and flow of materials into the
system.
As a result, there would be no requirement for hazardous area classification around the gas supply pipework, as the alarm would be set to activate at a small proportion of the lower explosive limit of the gas released, say 20% LEL, which would ensure that no flammable atmospheres may be generated. Regular natural gas detection leak checks should be conducted as a part of a preventive maintenance program as an additional control measure or adequate ventilation to dilute the vapour
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