Shenzhen ZhongNuo Inspection Technology Co., Ltd. specializes in the certification, calibration, and metrological services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment in various locations. We hold qualifications to serve nationwide, providing solutions to electrical safety and explosion-proof fire prevention issues for our clients, and contributing to safe production.
How often should various gas detectors be calibrated and inspected?
The recalibration period for instruments is typically one year, and the testing unit should determine it based on actual usage. During the secondary calibration process, if there are any doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repair.

Gas Standard Material
We use gas standard substances of the same type as the gas measured by the instrument, such as methane or ethane, or alternative substances like isopropanol can be used. If the instrument does not specify the type of gas being measured, the concentration of the gas, such as methane, ethane, or警设定点涨度的气, should be approximately 60% of the full scale. The uncertainty of the expanded gas standard substance is not more than % (k-1 standard substance greater than ±1%). The flow indication error of the repetitive dilution device should not be greater than 0.%. The concentration unit of the gas standard substance should be converted to match the indicating unit of the tested instrument when in use.

Verification Method
Appearance and structure
Inspect visually and by touch according to the requirements of 4.1
Logos and Branding
Inspect according to the requirements of Section 4.2.
Power-on inspection
Inspect visually and by touch, checking the alarm function and alarm action values as per requirements 4.3 in 5.3.4.
Introduce a standard gas substance with a concentration exceeding the alarm set point, causing the instrument to trigger an alarm. Observe whether the instrument's sound and light alarm functions normally and record the instrument's reading when the alarm is triggered. Repeat the measurement three times, and the arithmetic mean of the three readings is the instrument's alarm trigger value.

Regular Inspection Items for Environmental Gas Detection and Alarm Equipment in Workplaces:
Alarm sound and light (if applicable)
2. Low response value
3. Indication Error (for Gas Detectors/ Gas Detector Alarms)
4. Instrument Drift (in Portable Instruments)
5. Alarm Error (for Gas Detection Alarm/ Gas Alarm)
6. Pump-suction Instrument Gas Sampling Distance and Flow Rate (for Pump-suction Instruments)
7. Power Supply (for battery-powered instruments)
8. Response Time
9. Status Indicator (with wireless communication capability)
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarms, and toxic and harmful gas alarm instruments for regular inspections, metrological measurements, and calibration services. We provide qualifications to help clients address fire and explosion prevention issues.