Air monitor and gas monitor calibration and bump testing is an important topic in many industries, especially oil and gas. Many professionals use these monitors to protect themselves from hazardous gases and other airborne substances known to cause injury, illness, and death. It’s difficult or impossible to detect or judge atmospheric gas levels without a gas detector because many are odorless, colorless, and tasteless.
Gas monitors, like all equipment, are only as effective as the people using them. Failure to properly calibrate, test, and use gas monitors properly means you and your team risk exposure to hazardous gases or an oxygen-deficient worksite. Properly maintaining gas monitors helps protect everyone working at potentially hazardous job sites.
Gas Monitor Calibration Overview
Calibration and testing tell you how reliable and accurate your gas monitor is. Air monitor calibration and testing is done with a known, traceable concentration of hazardous gas to ensure that the monitor sensors are responding accurately and that the alarms function. Once calibrated, the instrument’s meters get reset to match the test gas, which ensures that all readings are accurate.
Because the responsiveness of monitor sensors can vary—workplace conditions such as temperature, humidity, and atmospheric pressure can all affect readings—it’s important that the sensors are calibrated in environmental conditions as close to the worksite conditions as possible.
Bump Testing vs. Calibration
Both bump testing and calibration are necessary to verify gas monitor functionality before use. Bump testing verifies that your gas monitor will detect the target gas in a work environment. When bump testing, you don’t have to worry about zeroing the meters or comparing the readout to the contents of the test gas. Bump testing should take place on a daily basis before the device is used. If the first bump test fails, a full calibration of the device is required.
Calibration is necessary in order to check the accuracy of your readings. This process allows instruments to self-correct to the appropriate level of sensitivity. This is especially important for older devices because the sensors will degrade over time and use: a device that can’t accurately read set values needs to be replaced. Any devices that have been dropped or otherwise damaged should be recalibrated as well. You might not need to recalibrate your monitor very often if it responds to test gas and the work environment conditions stay consistent.
When in doubt, refer to the owner’s manual and manufacturer’s guidelines. Start with a bump test to ensure that the device is working: if it fails or your work environment is subject to change, proceed with a full recalibration.
Frequency of Air Monitor Calibration
All gas monitor sensors experience calibration drift: the instrument’s reference points shift, which means the reading shifts and is no longer reliable. These instruments will still measure the quantity of gas present, but not be able to convert it into an accurate numerical reading. Calibrating monitors with traceable gas concentrations help to verify and update the instrument’s reference point.
According to OSHA, you should calibrate your instrument before each use to ensure that you have accurate readings. This is especially crucial if the work environment is subject to change or the monitor is older. Calibration takes about five minutes per monitor and should be worked into the schedule to ensure all employees have time to complete this step before they’re sent into the field. If a company or facility manages hundreds of individual gas monitors, it might be more practical to calibrate them according to the manufacturer’s recommendations, which might recommend recalibration every few months. Some units will automatically alert you when it’s time for recalibration.
No matter how frequently you calibrate your gas monitors, you should always keep a log of each monitor’s calibration history. Having the information documented is useful for later reference in case of an emergency or if one of the monitors needs to be repaired.Calibration and Testing Equipment
Calibration and bump testing your gas monitor requires the following equipment:
- Calibration gases in the target gases you’ll need. Check the expiration date before using it and store it in an accessible, dry, and room-temperature environment.
- Regulators to control the rate of calibration gas flow.
- Gas Detection Tubing to capture and funnel gas toward the air monitor.
- Calibration adaptors, caps, or cups to ensure that the calibration gas is trapped and directed over instrument sensors.
- If one exists for your monitors, a docking and calibration station could be useful for keeping your equipment in one place and make calibration and bump testing a more convenient process. A demand flow regulator will also be needed if you’re using a docking and calibration station.
How to Bump Test and Calibrate Your Monitors
Always refer to your owner’s manual when calibrating or testing your gas monitor: if you don’t have access to it, it might be available online, or you can contact the manufacturer directly for more information. The gas monitor calibration process tends to be similar for most models, with differences for manual calibration and automatic calibration.
To calibrate an individual monitor manually, start by zeroing the meter, which resets its reference point (this might require “zero air” gas). Make sure that your test gas isn’t expired and that the concentration is high enough to trigger the instrument’s alarm. If the gas is safe to use, apply the test gas to the monitor and check the instrument’s readings.
The readings should be within the acceptable range of the test gas concentration, which is typically ±10-20% of the test gas concentration. If the monitor does not recalibrate or the alarm isn’t triggered, try recalibrating the monitor, using a new test gas, or contacting the air monitor manufacturer for assistance.
This process requires a docking station for the monitors, which will also charge them. It tends to save time and reduce the chance of errors. Have your team ensure that the calibration has been completed before they take the monitors into the field. If the monitor fails to properly recalibrate automatically, the system will alert you. Docking stations will also update calibration records on the included software automatically.
Air and Gas Monitors from PK Safety
PK Safety has been a trusted safety expert for decades, and we continue to ensure that workers are safe, well-equipped, and as informed as possible. For more information about bump testing, calibration, or other worksite safety questions, you can contact our customer support team online or by calling 800.829.9580.