Functional safety
The detector is certified by INERIS (in process) to be in conformity with the
requirements of standard EN 50402 for SIL capability 1 and 2 for the CH
4
and HC
versions. Applicable since 2005, this standard is concerned with electrical
apparatuses for the detection and measurement of oxygen or toxic or flammable
gases or vapors, and defines the requirements relating to the safety function of
fixed gas detection systems.
The detector has been developed in conformity with standard EN/CEI 61508.
The safety function of the OLC/OLCT 100 detector is the detection of flammable
gases using catalytic technology and a 4-20 mA current output proportional to the
gas concentration expressed as a percentage of LEL, respectively from 0 to 100%
LEL. In the event of failure, the current will assume a fall-back value less than or
equal to 1 mA or greater than or equal to 23 mA.
The safety function is no longer valid:
After power has been switched on, while the measurement sensor is
stabilizing and during start-up tests, the output current shall be in
maintenance mode (2 mA).
When the push button is pressed (forcing the current to 4 mA), the output
current will be frozen at 4 mA.
Reliability data
These data are based on feedback from experience in the field. The analysis of
the information recorded during maintenance by our technical team has enabled
us to determine the following Probabilities of Failure on Demand under normal
conditions of use: