5 – Preventive maintenance
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Chapter 5 | Preventive
maintenance
Periodic checks enable the equipment and installation to remain in conformity
and ensure reliable detection. This chapter describes what preventative action
should be taken and at what intervals. Inspection and maintenance are carried
out in accordance with standards in force EN60079-17 or IEC 60079-17, with
whatever editions are in force or with other national standards.
Frequency of maintenance
Gas detectors are safety devices. OLDHAM recommends the regular testing of
fixed gas detection installations. This type of test consists of injecting the standard
gas into the detector at a sufficient concentration to activate the pre-set alarms. It
is to be understood that this test is in no way a replacement for a detector
calibration.
The frequency of gas tests depends on the industrial application where the
detector is in use. Frequent inspections should be made in the months following
the commissioning of the installation, and should then become more widely
spaced provided that no significant deviation is observed. The interval between
tests should not exceed 3 months. If a detector should fail to react in contact with
the gas, calibration is essential. The frequency of calibrations shall be appropriate
according to the results of the tests (humidity, temperature, dust, etc.); however, it
must not exceed one year.
The general manager should put safety procedures in place on-site. INDUSTRIAL
SCIENTIFIC cannot be held responsible for their enforcement.
To attain SIL capability level 1 in accordance with European standard EN
50402, Requirements relating to the safety operation of fixed gas
detection systems, the maintenance interval for explosive gas detectors
must be no more than 6 months. To obtain SIL capability level 2, the
maintenance interval must be no more than 3 months