Emerson Edition 4 Water Heater User Manual


 
2-1
Rosemount Tank Radar REX
Chapter 2 Safety
Installation Manual
308014EN, Edition 4
May 2013
2. Safety
Rosemount 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 personnel, precautions
must be taken to ensure that this atmosphere cannot be ignited. These
areas are called hazardous areas and equipment within these areas
must be 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 electrical faults in components,
are unable to cause ignition. Intrinsic safety is the only technique
accepted for Zone 0 hazardous areas. It is also safe for personnel and
allows equipment to be maintained without the need for a gas-free
certificate.
For example, temperature measurement with the DAU is intrinsically
safe.
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.
Note! For trouble shooting and repair work of components in or in connection
to intrinsically safe equipment, strict observance of the following rules is
necessary:
- Disconnect the power supply to the Radar Tank Gauge.
- Use a certified battery operated instrument only.
- Use Rosemount TankRadar REX original spare parts only.
Replacement with non-original spare parts may jeopardize the intrinsic
safety.