What are the standards for the testing of gas warning devices?
Appearance and functional inspection
1. Check appearance and other items
Check the appearance of the gas detector to avoid minor problems that may occur during transportation or production and assembly of the gas detector. We need to check whether the appearance of the gas detector is defective, cracked or damaged, and check whether the entire gas detector component structure is whole. At the same time, check the machine model, label, manufacturer name, and factory date on the gas detector body with the instructions or information given by the manufacturer one by one to ensure accuracy. At the same time, check the explosion-proof mark and measurement license of the gas detector. The logo, number and other contents must be complete and clear. Some documents can be requested from the manufacturer.
2. Power-on inspection
A gas detector requires a power source to work. It is usually powered by a built-in battery. We need to turn on the switch and check whether the gas detector is powered on normally. Some gas detectors are allowed to continue working by replacing the battery. Some gas detectors are powered by a built-in battery. The detector is equipped with a charger. For gas detectors equipped with chargers, we need to test whether the charger is charging normally. When the power is normal, we need to check whether the display screen of the gas detector displays normally.
3. Check whether the sound and light alarm of the instrument is normal.
For gas detectors with sound and light alarm signals, because they are powered by batteries, when under-voltage is displayed, they should be able to send out a sound or light indication signal that is clearly different from the alarm signal.
Indication error
The gas detector we purchased is used to detect gas concentration. The gas detector cannot display the gas concentration accurately. It has errors, but this error has a range. If it exceeds this range, it means This gas detector does not meet the standards. It has different indication errors for different gases. For example, it is normal for the oxygen indication error to be within ±0 or 5% VOL.
Alarm error
We mentioned the error of the displayed value above, so there is also a certain allowable error for the alarm value of the gas detector, because the instrument will be affected by various factors, and it is impossible to alarm at an accurate concentration every time. Therefore, the alarm concentration is allowed to have errors, as long as the error is within the standard range. The alarm errors are also different for different gases. For example, the alarm error for oxygen is within ±0 or 1% VOL.
Response time
Response time refers to the time required for the gas detector's indication value to rise from zero to 90% of the stable indication value that the instrument should reach. This time is also required by standards. This standard is the same as indication error and alarm error. Different gases have different response times.
Insulation withstand voltage
There are also some insulation withstand voltage standards that must be met for gas detectors. The standard requirements are: at normal temperature: ≥100MΩ; after damp heat: ≥1MΩ. The insulation strength should be able to withstand 500V AC voltage lmin, and discharge and breakdown should not occur. Only when these are met will it mean that the gas detector meets the standards.
