Calibration and Bump Testing
What is Calibration
Every gas detector contains sensors that take readings of their surrounding atmosphere. Over time, the visual
reading displayed on the detector can drift and lose accuracy. In order to avoid getting inaccurate readings
a detector needs to be recalibrated regularly. Calibration does not replace a bump test, which is another
important component of a gas monitoring program.
Calibration involves applying a known concentration of gas to a detector while it is in calibration mode. The
instrument's electronic display reading will adjust to match the desired value based on the concentration
being applied, thus realigning the accuracy of your display.
One of the most frequently asked questions about calibration is how often it should be done. The amount of time
between calibrations can vary, but should at minimum follow the manufacturers' recommendations. You may need
to calibrate more often based on provincial regulations or your own company policies. The date and time of
each detector's calibrations should be recorded and tracked throughout the life of the detector.
Docking modules, such as the
MicroDock II from BW, can simplify this process by automatically performing your calibrations and storing
this information electronically. All you need to do is insert the detector into the module and press a few
buttons to begin the calibration. The MicroDock II takes care of the rest!
What is Bump Testing
Bump testing a close relative to calibration. While calibration is periodic maintenance to realign a gas detector's
readings, a bump test should be done daily (at least!) to verify that the sensors are actually functioning.
It only takes a few seconds, and is done by applying a known concentration of the target gas to make sure
that the detector goes into alarm mode when that gas reaches the sensors.
Ideally a gas detector should be bump tested at each shift change or every time it moves to a new user. At a
minimum it should be done once per day. This is because a detector's sensors can fail to alarm for a wide
variety of reasons:
- The sensor is at the end of its life
- The ports for the sensors have become blocked by dirt or debris
- One or more of the sensors has become damaged or 'poisoned' by any number of sources, including solvents,
silicones, or overexposure to combustible gases
The safest and best practice is to bump test each gas detector any time it is about to be used to protect a human life. Docking
stations such as BW Technology's MicroDock II will automate the bump test process and simplify your record
keeping. All you need to do is insert the detector into the module – it can even be set up to begin a bump
test as soon as a detector is inserted. The
takes care of the rest!