For one’s own protection, and that of all employees, it is essential to conduct regular bump/ function tests and it is stipulated in different regulations.
For portable/mobile gas detectors, the different regulations strongly recommend performing the bump test prior to daily use (or prior to each use in the case of shifts or when passing from one person to another).
Only with bump testing does possible damage come to light, which would not be identified from a visual inspection alone. The bump test should be performed regularly prior to entering the working area. This approach meets the current guidelines set out by the regulatory agencies.
Regular function testing is an established principle in national and international regulations.
Different regulations and guidelines internationally stipulate regular testing of mobile gas detectors.
A daily bump test is the fundamental requirement to ensure the proper function of a device.
The following overview shows relevant extracts from selection aid IEC/EN 60079-29-2:
All portable/transportable gas detection systems should be checked for functionality with a known concentration of flammable gas just prior to use (bump test).
Inspection through a bump test, especially when using the gas detector in conjunction with a gas-free permit.
…
Ideally, the user would perform a functional test with a known gas concentration (in addition to a visual inspection and check of the documentation).
Alternatively, a (re)calibration can/should be performed. Ideally by the same personnel tasked with device maintenance.
The following overview shows relevant extracts from selection aid OSHA - SHIB 05-04-2004:
When to Perform a Bump Test and When to Perform a Full Calibration In the past, there has been some confusion regarding proper calibration procedures and frequency.
To clarify this issue, ISEA updated its position statement on instrument calibration in 2010, stating: “A bump test … or calibration check of portable gas monitors should be conducted before each day's use in accordance with the manufacturer's instructions.”
If an instrument fails a bump test or a calibration check, the operator should perform a full calibration on it before using it. If the instrument fails the full calibration, the employer should remove it from service.
The following overview shows relevant extracts from selection aid BG RCI T021 & T023:
Function testing:
..task for suitable test gases, gas mixtures for testing the display and alarm function. The employer must define a criterion which is used to determine whether the device has passed the test. The response time of the device must be taken into account here. Observe the recommendations in the manufacturer's operating instructions.
Note: a simple zeroing test in the ambient air does not meet the requirements of this function test. Visual inspection and function testing must be performed on each working day or prior to each working shift.
Furthermore, bump testing should be performed after exceptional situations (device was dropped) or when there is a risk that the device is damaged (sensor poisoning).
For more information on the importance of bump testing including the reason why visual testing is NOT enough click here.
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This article was adapted from content provided by Dräger