Rosemount TankRadar Rex DAU 2100, Руководство по обслуживанию

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2-1
Rosemount Tank Radar Rex
Chapter 2 Safety
Service Manual
308012En, Ed.2
May 2013
2. Safety
TankRadar Rex equipment is often used in areas where flammable
materials are handled and where an explosive atmosphere may be
present. To protect both the plant and the staff, precautions must be
taken to ensure that this atmosphere cannot be ignited. These areas are
called hazardous areas and equipment within these areas are explosion
protected.
A number of different explosion protection techniques have been
developed over the years. Intrinsic safety and explosion proof (or flame
proof) safety are two techniques.
2.1 Intrinsic safety
Intrinsic safety, IS, is based on the principle of restricting electrical
energy available in hazardous-area circuits such that any sparks or hot
surfaces, that may occur as a result of up to two electrical faults in
components, are too weak to cause ignition. Intrinsic safety is the only
technique accepted for Zone 0 (high risk) hazardous areas. It is also safe
for personnel and allows equipment to be maintained without the need
for a gas-free certificate.
The basic principles of intrinsic safety are:
• All flammable materials are grouped according to the energy
needed to ignite them.
• Equipment located in hazardous areas are classified according to
the maximum surface temperature that it can produce and this
must be safe with the flammable gases that may be present.
• Hazardous areas are classified according to the probability that an
explosive atmosphere is present, and this dictates whether or not
a particular explosion protection technique may be used.