Monitoring Basics Part 2

Calibration & Bump Testing

Calibration and bump testing are often areas of confusion. Bump testing and calibration are two completely separate operations, though they are performed in a similar fashion.

Calibration is the process of resetting established concentrations within the monitor. Typically a calibration begins with a zero calibration. To perform a zero calibration the user applies a ‘zero gas’ to the sensor. A zero gas is a gas that truly has no concentration of the gas the sensor detects. This differs from a fresh air zero because it uses the zero gas instead of normal air, which can have trace amounts of gases. The zero calibration resets what exactly zero amount of the gas ‘looks like’ to the monitor.

The zero calibration is typically followed by a span calibration. Span gas values can be adjusted on many monitors, but the gas must meet the concentration programed into the monitor. The span calibration gives a secondary point of reference for the monitor to determine concentrations. Some monitors will utilize two span calibrations at different concentrations rather than a zero and a span. Two points of reference are necessary for all calibrations in order for the monitor to accurately extrapolate concentrations. If only one point of reference is given, the calibration is not complete and the monitor is likely not accurate.

Most monitors requiring monthly calibration. There are a handful of monitors that only require a quarterly calibration and a few that do not need calibrated for the life of the monitor.

Bump testing is the process of verifying system function in the monitor. Bump testing still requires the monitor to be connected to a gas, but the bump test does not reset the parameters of the monitor like a calibration does. The bump test simply is verification that the monitor will detect gas and alarm appropriately. Most monitors require daily bump testing.

*Unless specific citations are shown, all answers are based on interpretations provided by authorized officials. As such, all information is deemed reliable, but not guaranteed.