{"id":73806,"date":"2020-12-27T06:00:30","date_gmt":"2020-12-27T04:00:30","guid":{"rendered":"http:\/\/psaafrica.co.za\/mg\/a-review-of-the-gas-detection-technologies-available-to-you-copy\/"},"modified":"2020-12-17T11:51:58","modified_gmt":"2020-12-17T09:51:58","slug":"the-difference-between-a-bump-test-and-callibration","status":"publish","type":"post","link":"https:\/\/psaafrica.co.za\/mg\/the-difference-between-a-bump-test-and-callibration\/","title":{"rendered":"What\u2019s the Difference Between a Bump Test and Calibration\u2014and Why Should You Care?"},"content":{"rendered":"
\n

If you work with direct-reading portable gas monitors (DRPGMs) to check oxygen levels and look for toxic or combustible gases, you\u2019re likely familiar with the concepts of bump testing and calibration. But if you were given an on-the-spot pop quiz on the subject, could you tell the difference between these terms?<\/p>\n

The main\u00a0difference between a bump test and calibration\u00a0is that a bump test determines whether a DRPGM can detect if a possibly hazardous gas is present, while calibration checks that equipment is accurate.<\/strong><\/p>\n

But it\u2019s a little more complicated than that, and getting to know more about bump tests, the two types of calibration, and related best practices can help you keep these distinctions top of mind\u2014and use them correctly.<\/p>\n

<\/p>\n<\/div>\n

<\/div>\n
\n

Defining Differences<\/h2>\n

Direct-reading portable gas monitors fall under the responsibilities of safety equipment trade organization the\u00a0International Safety Equipment Association (ISEA), which released a 2010\u00a0statement\u00a0to improve consistency in how people use, test, and maintain DRPGMs. In that statement, the organization was careful to flesh out the differences between a bump test, calibration check, and full calibration as well as advise how and when to test with each method.<\/p>\n

So What\u2019s a Bump Test?<\/h3>\n

The\u00a0ISEA defines a\u00a0bump test<\/b>\u00a0as a<\/p>\n

\u201cqualitative function check where a challenge gas is passed over the sensor(s) at a concentration and exposure time sufficient to activate all alarm indicators to present at least their lower alarm setting. [\u2026] This is typically dependent on the response time of the sensor(s) or a minimum level of response achieved, such as 80% of gas concentration applied.\u201d<\/i><\/p>\n

This checks whether sensors and alarms are working as intended, and failure might indicate that a blockage is present. In sum, bump testing assesses function, not accuracy.<\/p>\n

How Is Calibration Different?<\/h3>\n

Part of the confusion surrounding bump testing versus calibration lies in the fact that\u00a0calibration checks\u00a0<\/i>and\u00a0full calibration<\/i><\/strong>\u00a0are two different things<\/strong>. Both of these types of calibration can test a DRPGM\u2019s accuracy, but they\u2019re used in different circumstances.<\/p>\n

A\u00a0calibration check<\/b>, according to the ISEA, is a<\/p>\n

\u201cquantitative test utilizing a known traceable concentration of test gas to demonstrate that the sensor(s) and alarms respond to the gas within manufacturer\u2019s acceptable limits.\u201d<\/i><\/p>\n

Calibration checks start by \u201czeroing\u201d a DRPGM (resetting it to a reference point determined by the manufacturer) and testing that alarms go off after applying a high enough concentration of test gas. The resulting sensor reading should match the concentration listed on the test gas container. The ISEA says that a device is accurate within an\u00a0acceptable range\u00a0that\u2019s \u201ctypically \u00b110-20% of the test gas concentration applied unless otherwise specified by the manufacturer, internal company policy, or a regulatory agency.\u201d<\/p>\n

The\u00a0ISEA guideline describes\u00a0full calibration<\/b>\u00a0as<\/p>\n

\u201c[t]he adjustment of the sensor(s) response to match the desired value compared to a known traceable concentration of test gas.\u201d<\/i><\/p>\n

This adjustment accounts for naturally occurring drifting and other environmental factors. Specially trained, qualified personnel are the only people permitted to perform full calibrations.<\/p>\n

Bump Up Your Bump Test Knowledge and Avoid Calibration Frustration<\/h2>\n

Now that you know the differences in definition, let\u2019s take a look at some tips and tricks for using both bump tests and calibration.<\/p>\n

When to Test<\/h3>\n

Perform a bump test and calibration check every single day before anyone uses the DRPGM that day (and according to manufacturer\u2019s instructions).<\/p>\n

The DRPGM\u2019s manufacturer\u2019s guidelines\u2014plus internal policies and regulatory recommendations\u2014determine exactly\u00a0how and how often to fully calibrate\u00a0that particular DRPGM. Full calibration is also necessary if a bump test or calibration check fails. You can perform a full calibration twice, but after two \u201cfails,\u201d the device must be pulled from use. Full calibrations should also take place after the following\u00a0types of exposures:<\/p>\n