Maintenance performed during a site shutdown often takes in gas detection systems, including checking expiry dates and calibration. For some, shutdowns also increase the use of portable and transportable monitors, as fixed systems are being maintained and extra personnel come on site to work. Every year, around this time, we get a significant increase in calls about problems arising during site shutdown. Many of these could have been avoided with a little planning and forethought.
Sensors at or close to expiry should be replaced during shutdown. We would recommend replacing a sensor with three months or less shelf life remaining rather than recalibrating it. However, because of their limited life from date of manufacture, companies tend not to hold sensors in stock. Those who haven’t planned ahead may well find themselves making a call for urgent sensor replacements so they can get their gas detection system back on line. By maintaining a register of sensors and their expiry dates, a site would know which sensors were expiring and could order them in before the shutdown.
Sensors not being replaced should be recalibrated. Again, without preparation, it is surprisingly common to find companies who can’t conduct valid testing, because their gas canisters have expired since they were last used. Another potential cause for delay is if any gases used (or produced) on site have changed and the available gas canisters haven’t been changed to reflect this. Either way, calibration cannot be performed until new gas is obtained from the manufacturer. Prior to shutdown, a review of gases used or produced on site, as well as a check on the test gas canisters in stock, would mean that the correct gases, within shelf life, were readily available for sensor calibrations.
Another common call we receive at this time of year relates to control panels. The problem is noticed when the power is turned off for maintenance. Most control panels have a battery back-up, intended to maintain site protection during short power outages of a few hours at most. These batteries require maintenance, and we recommend replacing them every two years or so. If they don’t receive appropriate attention, the power being cut can drain residual power in the battery. When the power is restored, the battery no longer provides the required system back-up, and the control panel goes into fault. A pre-shutdown plan would help avoid such issues. Adding a test of the control panel battery to the other routine maintenance carried out on the gas detection system would ensure it was in good working order.
A little bit of preparation always saves a lot of time and inconvenience. By developing a pre-shutdown plan, sites could circumvent gas detection related problems that arise during the shutdown season.