It is essential to be clear and upfront about this fact as it is probably the biggest difference between a bump test and a calibration. It seems to be a common misconception that a bump test can replace a regular calibration!
This frame of mind can be dangerous - so let's define both a Bump Test and a Calibration so you can be confident that your gas detector is up to standard.
Bump testing focuses on the sensor and alarm function of your portable gas detector - making sure they are working well together. By exposing your portable gas detector to a known concentration of gas (only briefly), a bump test can ensure that the alarm is working correctly.
Also known as 'verification' or 'challenge', a bump test demonstrates the overall operation of the portable gas detector, however a bump test does not check the reading for accuracy. Bump testing can be done in less than a minute and is recommended at the start of the day.
Calibration on a regular basis ensures your portable gas detector has accurate readings. If the readings aren't accurate for whatever reason, adjustments can be made at calibration to ensure the gas detector doesn't let you down.
This is something that cannot be done during a bump test, hence, why a calibration is equally as important in the maintenance of your portable gas detector and therefore effectiveness of your work.
It's generally recommended you get your portable gas detector calibrated at least every 6 months. Please check with the manual that came with your portable gas detector to find out the manufacturer's advice on regularity.