Maintenance & calibration of gas detectors

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Whatever the sensor technology, the calibration of a gas detector consists of setting the zero and adjusting the sensitivity (Span). This is an essential and recurring operation for both portable and fixed gas detectors.

The "zero adjustment" configures the sensor so that the ambient air is used as a reference value, it is therefore imperative that this "reference" air is perfectly "pure" so as not to affect the measurements. In case of doubt, it will be necessary to prefer a standard gas cylinder "zero grade air" (synthetic air) rather than a zero adjustment in the open air. 

This is even more important for CO2 detectors (carbon dioxide) because it is naturally present in the ambient air (about 400 ppm) and will distort the measured values of CO2. For this gas, the "zero" setting must be done with "zero grade air".

The sensitivity adjustment is ideally done with a standard gas cylinder of the gas to be measured with a concentration between 20% and 80% of the measurement range, taking care to be able to trigger all the alarm thresholds of the gas detector. 

In certain cases where there are no standard gas cylinders to calibrate the gas detector (not all gases are available for sale), an interfering gas may be used with all the necessary precautions (and relative uncertainties). 

After each calibration in the workshop or performed on site, a certificate must be produced clearly specifying the references and characteristics of the device, the measurement range of each of the sensors as well as the batch numbers and validity dates of the standard gas cylinders used. GazDetect provides a calibration certificate for all types of devices: multi-gas or single-gas detectors, area gas monitors, fixed gas detectors, etc. 

The calibration certificate must be dated and indicate its validity period (date of next calibration). 

To check the proper functioning of the device between calibrations or before entering a confined space, a functional test called “bump test” or " gas test " is highly recommended. This is a prerogative of the CATEC system (Certificate of Ability to Work in Confined Spaces in the Drinking Water and Sanitation Sector). 

This verification of the gas detector is simply carried out by applying a known concentration of gas to confirm the performance of the sensor (response time to the gas) and the activation of the different alarm thresholds of the device.

For maintenance operations, periodic checks or calibration of gas detectors, we offer a very wide range of standard or customized gas mixes in light disposable cylinders. The available offer covers a complete range from simple binary LEL mixes (for explosive gases), to complex and multiple mixes used in laboratories with very low concentration levels. 

The gas mixtures are mixed by gravimetry generally applying the principles of ISO6142. They guarantee precision, optimal stability and maximum shelf life. 

⇒ See calibration gas cylinders

We offer to all our customers - FOR FREE - the management and monitoring of their gas detectors via the application My GazDetect. After identification, you can access your personalized space where you can program alerts of device returns (or request for on-site intervention), view or print your calibration certificates, manage your gas detectors fleet: assign, sort, classify your devices and instantly control the gas detectors that need to be calibrated ... 

⇒ See MyGazDetect : Calibration management