Cal Gas vs Bump Gas. We added this resources section to our website to try and offer a quick reference glossary, a chemical index, a technical and laymen definition of calibration gas and this explanation of the differences between cal gas/tests and bump gas/test. Hopefully, this will help you should you run across a term, a gas or a procedure that you aren’t familiar with.
Cal Gas Warehouse runs into this situation, quite frequently, so we added a brief description about the differences between cal gas (calibration gas and calgas), calibrations and bump gas and bump testing.
A calibration is typically performed at the end of a defined time interval. Manufacturers of gas detectors each have different windows of how long a gas detector can go before a calibration is needed. Typically, those windows are anywhere from 30 days to 90 days in length. A calibration DOES NOT absolve one of their responsibility to perform a bump test. A calibration and a bump test are unrelated and their purpose and result are entirely different. This concept is probably the most misunderstood of any we encounter. Please refer to our glossary to completely understand what is achieved during calibration.
A bump test should be performed, at minimum, at the beginning of each days use (see OSHA health bulletin # SHIB 09-30-2013 for further information) or after, what we call an event. IE: The gas detector was dropped, the unit was exposed to toxic gases and the sensors spike or something as simple as an employee throwing a tool in the back of the truck that lands on a unit. Cal Gas Warehouse recommends bump testing every time the unit is powered up for use in a potentially hazardous area. The bottom line is, bump tests save lives! The single last chance you have to make sure your gas detector’s lights and alarms (audible and physical) are functioning properly. Please do not conflate the two, a calibration and a bump test. MANY in the industry think if they are within their defined calibration window, there is no need to bump test. This is FALSE and it is dangerous. A bump test has nothing to do with a calibration.
The confusion may be that some manufacturers calibration stations use the same gas to calibrate as they do to bump test. There is of course, no problem with this, the problem seems to stem from people thinking because both tests are performed off of the same cylinder and the same station, that if they calibrate then they don’t need to bump test.
Briefly, the purpose of calibration, again, is to establish that allowable safe range (setting the walls in place – see glossary) for the different gases you are protecting yourself against and the purpose of the bump test is to actually make your unit alarm by running a more than allowable, toxic gas to pass across the sensors.
The result of calibration should be that your gas detector has established the safe span/range (typically the default setting from the factory) of those gases you are testing for and the result of the bump test should be lights flashing, an audible alarm and vibration.
The length of a successful calibration will vary depending on the manufacturer, the amount of time between calibrations, actual use (or lack of) of the detector and whether you calibrate by hand or use a calibration station.
The length of a bump test can literally be a few seconds to a few minutes. Again, if you are bump testing with an aerosol, it should be seconds. If you are bump testing with a calibration station, some manufacturers bump tests take between 1 to 3 minutes.
Cal Gas Warehouse has the benefit of sharing a building with our sister company Frederick Supply. They perform calibrations all day long. We hear the confusion from customers and wanted to have an easy reference to solve any confusion that is out there.