A paradigm shift in maintenance
September 5, 2008
Gas detection instruments are like any other piece of equipment â€” they need maintenance to make sure they’re working properly. But more often than not, maintenance of fixed gas detection systems is overlooked, or at least done less frequently than with portable instruments.
Reduce hands-on testing
Almost a decade since the appearance of the first portable instrument “docking” system, a breakthrough technology has enabled similar cost and time savings with the automation of calibration and diagnostic testing of fixed or wall-mounted gas detectors.
With two-way communication, this fixed “docking” system for remote calibration and automated record-keeping reduces human intervention and encourages preventive maintenance. The docking system performs function tests and calibrations on a routine schedule, or on demand remotely from a computer console, eliminating the need to send a person around to each detector.
A function test consists of applying a known concentration of gas to a sensor to ensure that the response exceeds the lowest alarm set-point. If the sensor does not respond properly, the filter may be blocked by dirt or debris, or the sensor may need to be calibrated. Function tests are done to ensure that the sensors and detector are still working properly. Without performing routine function tests, how can you know if the sensors are still working?
Automating this “bump” test process increases the reliability of the system, as well as increasing safety within the facility. Safety levels will increase because instruments are being tested and proven to work, and the personal safety of technicians will also increase as a result of their not having to conduct these tests while standing on ladders, lifts, or in hazardous environments.
Function testing not only ensures that the instruments are working properly, but also conditions the sensors. Sensors such as chlorine need to see chlorine gas regularly in order to be accurate and responsive.
Keep calibrations current
Calibrations should be performed routinely. If a sensor fails, it should be replaced and the new sensor calibrated after it has been installed in the detector.
Manufacturers’ recommendations on calibration flow rate and calibration concentrations should be followed to achieve the most accurate and precise calibration. Calibration gas should be checked to make sure it has not expired and that it meets the manufacturer’s specifications.
The same worker concerns for function testing also exist for calibration. Automating this process will increase sensor accuracy, safety and reliability of the gas detection system.
Stay on schedule
Maintenance should be performed regularly on fixed gas detection systems. Many manufacturers recommend function testing on a monthly basis, and sensor calibrations should be performed at least once a quarter. The frequency of maintenance is best determined by end-user policy or local regulations.
Automating the maintenance program through an integrated control system will ensure that instruments are properly maintained and running. The “docking” station allows users to set the maintenance program to their own schedule so that function tests can be run weekly and calibrations conducted monthly. At any time a technician can use the system’s interface to remote-start a function test or calibration on any instrument in the field. This allows for exception testing or for users to conduct tests at more opportune times.
Store records in a common database
The automated system also keeps track of all of the data in a common database. This eliminates the need to manually write details into a logbook. Keeping all data in one common area and making it easy to access is a significant improvement over current practices, and is quickly becoming “best practice” in the industry.
Replenish parts automatically
Once a problem is discovered, new equipment needs to be ordered. Replenishment parts programs tied to the docking system facilitate replacement sensors to be automatically sent out when failures are predicted. This allows users to receive a new sensor before the current sensor dies, eliminating downtime and increasing safety.
The fixed docking system also monitors calibration gas usage and filter life. Once gas levels are determined to be getting low, the system will notify the user with a low cylinder warning. This allows the user to reorder calibration gas before a cylinder actually runs out.