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3.2 Siting Recommendations
Location of Gas Detectors
Each installation needs to be considered in its own right, with reference to safety
authorities and in compliance with mandatory local safety regulations. The sensor
must be operated in accordance with the User Manual to maintain safety, reliability
and to preserve safety integrity where applicable.
It is important that sensors are located in positions determined in consultation
with those who have specialised knowledge of the plant or installation and of the
principles of gas dispersion. Reference should also be made to those responsible
for the engineering layout and topology of the plant as they will be most familiar
with the nature of the potential dangers and the most likely sources of gas release.
It is also important to recognise that the characteristics of the gas source can be
influenced by many factors; including the relative density or buoyancy of the gas,
the pressure at the point of release, the ambient temperature and the ventilation of
the site.
Sensor coverage cannot be simply expressed in terms of ‘number per unit area’.
Sensors need to be sited where they are capable of monitoring those parts of a
plant where gas may accumulate or where a source of gas release is expected
to occur. This way the earliest possible warning of a gas release can be given to
initiate shutdown functions, alarm functions or safe evacuation of the premises.
Sensor Management
A very important part of an efficient gas monitoring system is the training of
plant personnel in operation and maintenance of the sensors and the complete
monitoring system. Training can be provided by qualified Trolex application
engineers.
Once a sensor installation is complete, the sensor locations and types should be
formally recorded and a planned test and maintenance procedure instituted.
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