Measuring Range: The Core of Verifying Combustible Gas Detector Performance
It is very important to sample and detect the concentration of various gases or vapors at the top, middle, and bottom of a confined space. Some gases are lighter than air and can be collected in the upper part of a closed space; Some gases have a heavier specific gravity than air and can be found at the bottom of enclosed spaces; There are other gases with a specific gravity almost as heavy as air that can be detected in the middle of a confined space. Sampling at different heights and continuous detection by the detector based on the actual situation, we will find that the detection results are different.
So, what is the specific range of a combustible gas detector?
Firstly, sensors from different alarm instrument manufacturers have different response coefficients for combustible gas range calibration, which should be based on the values provided by the manufacturers,
Secondly, the range of a gas detector is an inherent property of the instrument and cannot be changed. Generally, the range of a combustible gas detector is 0-100% LEL, but it cannot be the same. For actual situations, please refer to the information provided by the manufacturer.
Thirdly, the methane calibration gas you have on hand does not have a relevant concentration unit. Is it 2.5% VOL (volume ratio) or 2.5% LEL (lower explosive limit)? The difference between the two is significant, and the lower explosive limit of methane is: lower explosive limit% (V/V): 5.3.
a, If you are a methane calibration gas with a volume ratio of 2.5% VOL, then the conversion is: 2.5% VOL=47% LEL. When calibrating there, the value should be set to 47
b, If you are using a 2.5% LEL (lower explosive limit) methane calibration gas, you can simply set it to 2.5 when calibrating (such low concentration calibration gas should be relatively rare, so this possibility is unlikely)
If maintenance is not emphasized, it will cause the combustible gas detector to be obstructed, resulting in errors or failure to detect. Therefore, regular cleaning and maintenance of combustible gas detectors is an important task to prevent malfunctions.
