RAE Systems recommends that their detectors are checked daily before use for accuracy by exposing the instrument to a known concentration or source of calibration gas. Accuracy of the sensor should be verified to guard against loss of sensitivity due to poisoning, desiccation, immersion, or aging of the sensors and damage.
RAE Systems has a tiered approach to performing checks:
Bump Check: the monitor is shown calibration gas and may go into alarm.
Field Verification: is when the gas detector is shown a pre-determined amount of gas and the user has to verify that the readings are within a predefined amount. This amount is typically ±10% or ±15% of the gas concentration.
Full Check: is when the detector is shown a pre-determined amount of gas and the readings are adjusted (either automatically with a calibration station, or manually) to meet the certified concentration.
Factory Check: The detector is returned to Active Environmental Solutions factory-certified service centre for extensive testing, adjustment and firmware upgrades (if required).
Weekly calibrations of your detector are a good starting point for general use, but the frequency should be determined by the level of threat to workers. If the threat to workers is high, the more frequently the calibration test should be performed.
The safest method to protect workers is to perform a test on the detector, with a known concentration of calibration gas, daily before use.
RAE Systems Technical Note TN-148 titled “Defining the Interval between Calibration Checks” is recommended reading for RAE Systems detectors.