Calibration vs Bump Test – What is the difference between
One common question is: Should we perform a bump test or a calibration check? Understanding the difference between these two processes is essential for maintaining accurate gas detection.
What is Calibration?
Calibration is the process of comparing a device’s measurements to a known standard to ensure accuracy.
When calibrating a gas monitor, the detector’s response is reset against a known concentration of target gas, usually balanced in synthetic air or nitrogen. This involves exposing the sensors to the calibration gas and either:
- Allowing the instrument to automatically adjust its readings, or
- Manually adjusting the readings to match the known concentration.
What is a Bump Test?
A bump test is a quick way to check if a monitor’s sensors are responding correctly. It involves exposing the device to a known gas concentration and verifying that the readings are within an acceptable range (typically ±10% accuracy).
Unlike calibration, a bump test does not adjust the instrument’s accuracy or calibrate the sensors. Instead, it simply confirms whether the sensors are detecting gas as expected. If a bump test indicates a potential issue, a full calibration is necessary.
How Often Should You Calibrate or Bump Test Your Monitor?
Not sure how often to perform these checks? The frequency depends on the instrument you use.
For example, if you’re using the Dräger X-am 2500 Gas Detector, the standard 4-gas monitor (LEL, CO, H₂S, O₂) should be calibrated every six months.
As for bump tests, the Health and Safety Executive (HSE) recommends testing before each day’s use, following the manufacturer’s instructions.
If you need more information or you have any enquiry, please contact us on 02920 759 683 or email our team at [email protected].
Revised by Emma Curthoys (20/02/2025)
