Calibration and Bump Testing of Portable Gas Monitors

Why are bump testing and instrument calibration important?

Portable gas monitors  detect unseen hazards

and measure the levels of hazardous gases. These instruments detect the presence of oxygen-deficient, explosive and/or  toxic

gases. Exposure to these conditions can have serious health  effects,  and even  result in death. Properly maintaining  your equipment can save  lives.


What is the difference between full calibration, calibration check and bump testing?


Full Calibration – Adjusting the sensor’s response to match the desired value compared to a known traceable concentration of test gas

Calibration Check – Using a known traceable concentration of test gas to show that the sensors  and alarms respond to

the gas within manufacturer’s acceptable limits

Bump Test (Function Check) – Passing a known concentration of gas over the sensors at a level and exposure time strong enough to activate all alarms


What is the ISEA?

The International Safety Equipment Association

(ISEA) is a leading  national trade  association for manufacturers of safety and health  equipment, including portable gas monitors.

When did the ISEA update their calibration guidelines?

In 2010, the ISEA updated and clarified their

guidelines on the frequency and types  of tests and checks needed to make sure these monitors function properly at all times.


These revisions include:

  • Expanding the scope of the guideline to include all workplace settings (not just confined spaces)
  • Emphasizing to users, employers and regulatory agencies the importance of making sure that portable gas monitors function properly



How often does the ISEA recommend performing calibration and bump testing?

Conduct a full calibration at regular intervals,

according to the manufacturer’s instructions.


Conduct a bump test or calibration check of portable gas monitors before each  day’s use, according to the manufacturer’s instructions.


NOTE:  If any portable gas monitor fails a bump test or a calibration check, you must fully calibrate the monitor before further use. Otherwise you must remove it from service

Can an employer be cited for not following recommendations for calibration and bump testing?

Failure to follow the manufacturer’s instructions

on use and maintenance of the monitor may result in the issuance of a violation. This is determined on a case by case basis.


Source: Public Employee Safety and Health