Piping in hazardous area
Piping in hazardous area
(OP)
Why a pipeline(or a reactor) containing a fluid with its temperature much higher than AIT can exist in an electrically classified hazardous area ?
Shih-Pin Yeh
Shih-Pin Yeh
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RE: Piping in hazardous area
Mike Halloran
Pembroke Pines, FL, USA
RE: Piping in hazardous area
Bill
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"Why not the best?"
Jimmy Carter
RE: Piping in hazardous area
Keith Cress
kcress - http://www.flaminsystems.com
RE: Piping in hazardous area
Piping and equipment with surface temperatures above the AIT of mixtures that might be released from the plant during a leakage event are frequently present in classified areas too. If you have a leak in that case, you are likely to have a fire irrespective of whether or not the electrical devices (instruments, motors etc.) are designed so that they themselves are not likely to be sources of ignition, i.e. irrespective of the area classification. It is important not to use area classification for something it is not intended. Area classification will make a simple operation like drum decanting, greatly safer- but it is of little protective use on a fired reboiler for instance (and there are plenty of those in chemical plants).
RE: Piping in hazardous area
RE: Piping in hazardous area
Look in your copy of the NEC for the definition of classified areas.
Bill
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"Why not the best?"
Jimmy Carter
RE: Piping in hazardous area
Area classification significantly reduces the risk that electrical devices will be the source of a fire. However, in hazardous areas that already contain a non-electrical source of ignition such as hot pipe, a burner, the exhaust of an engine... area classification does nothing but give you a false sense of security. Instead, you need another means to mitigate the risk of fire and explosion: ventilation, layout, reduction in leakage points, gas detection, fire detection and suppression etc.
RE: Piping in hazardous area
However, for the purpose of electrical installations, the area classification is addressed in the electrical codes, NEC and CEC in the US and Canada.
The electrical area classification is concerned with preventing ignition of flammable substances by the operation or mis-operation of electrical devices.
The appropriate classification is determined by the electrical codes and then the accepted wiring methods are determined by the codes.
Auto Ignition of leaking hot fluids, but is not an electrical issue.
Bill
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"Why not the best?"
Jimmy Carter