Bump testing gas detectors can save lives
A gas detector only protects the employee if the entire unit is working correctly. The battery and display may appear normal even if the sensors, alarms or air inlets are not responding as they should. Regular bump tests allow you to check that the gas detector responds to gas and triggers an alarm in time.
A gas detector being switched on is not enough
When a portable gas detector is switched on, the employee can see that the display and battery are working. However, this does not necessarily indicate whether the sensors are responding correctly to gas, whether the alarms are working, or whether openings are blocked by dirt.
Sensors can also be inhibited by unsuitable cleaning agents. Alcohol can damage electrochemical sensors, while silicone-based products can deactivate catalytic bead sensors used to measure LEL gases such as methane, pentane and propane. In such cases, the detector may still show a normal reading even though it does not trigger an alarm at dangerous gas levels.
Bump testing checks the functionality of the entire detector
A bump test is a practical functional check in which the gas detector is briefly exposed to a known concentration of the gas it is intended to detect. The test confirms that the sensors respond to the gas, that the display shows the response, and that the audible and visual alarms activate correctly.
The reading is compared with the gas concentration stated on the test gas cylinder. If the detector triggers an alarm within an acceptable range, typically within 10%, it is working correctly. If the results are not obtained within an acceptable time, or if it takes more than 30-40 seconds to trigger an alarm, the gas detector should not be used until a full calibration has been carried out.
Make bump testing a regular part of the working day
Bump tests are often skipped because they are seen as time-consuming, cumbersome or unnecessary when there is no explicit legal requirement. In practice, a bump test typically takes 20-30 seconds, and many systems can perform the test semi-automatically or fully automatically.
The best systems can be configured so that the employee simply inserts the gas detector, after which the system automatically supplies gas and measures the result. This requires little or no training and makes it easier to establish the procedure as a regular safety routine.
- Carry out bump tests regularly, ideally as part of the start-of-day routine
- Use the correct test gas for the gas detector and gas type being checked
- Check that the sensors, display and alarms respond correctly
- Take the gas detector out of use if it does not trigger an alarm within an acceptable time
- Avoid cleaning agents that could inhibit or damage the sensors
- Follow the manual and the manufacturer’s instructions for cleaning and maintenance
- Remember that bump testing does not replace regular inspection, calibration and servicing
Small routines can prevent serious accidents
Data shows a clear link between bump test intervals and gas detector failures. Gas detectors that are bump tested daily have an average failure rate of 0.3%. Gas detectors that are only bump tested every 20 days have an average failure rate twice as high.
There can be serious consequences if a faulty gas detector is only identified during a dangerous situation. A sensor may be blocked, inhibited or poisoned without any visible signs, so the employee may believe that the equipment is providing protection even though it does not trigger an alarm at high gas levels.
Regular bump tests are therefore a simple way to improve personal safety. The test does not replace the need for specialist servicing and calibration, but it provides an important daily check that the gas detector responds when it matters.
Get your gas detection and servicing sorted
Hans Buch provides advice on gas detectors and testing solutions that can make bump testing a simple and regular part of your safety procedures.
Get help with selecting, commissioning, calibrating and servicing gas detection equipment for your workplace.
Brian Beck Faymonville
Sales Engineer
Teit From Løvstrøm
Product Manager