Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and metrological services for gas alarms, combustible gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We offer nationwide services to address electrical safety and explosion-proof fire prevention issues for clients, promoting safe production.
Appearance and structure
The instrument should not have any surface damage that affects its normal operation. The surface of newly manufactured instruments should be smooth and even, with a uniform paint and plating layer, free of peeling or rusting.
The instruments offer reliable connections, and all dials or buttons should operate and control normally.
Logos and Branding
Instrument name, model, manufacturer, date of manufacture, serial number, explosion-proof marking and number, as well as the manufacturing metrological instrument license marking and number for domestically produced instruments should be clear.

Standard for calibration and verification of flammable and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm of Combustible Gases and Toxic Gases in Petroleum and Chemical Industry"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplaces
JJG 693-2011 "Regulation for the Verification of Combustible Gas Detectors"

Regular inspection items for environmental gas detection and alarm instruments in the workplace:
1. Alarm sound and light (if applicable)
2. Low response value
3. Indicating Error (for Gas Detectors/Gas Detector Alarms)
4. Instrument Drift (in portable instruments)
5. Alarm Error (for Gas Detection Alarm / Gas Alarm)
6. Pump-actuated instrument gas collection distance and flow rate (for pump-actuated instruments)
7. Power Supply (for battery-powered instruments)
8. Response Time
9. Status Indicator (with Wireless Communication Function)

The calibration cycle for flammable gas detectors is typically once a year.
According to the standard JJG 693-2011 "Flammable Gas Detectors," the calibration period for flammable gas detectors typically does not exceed 1 year. This means that under normal circumstances, a comprehensive calibration and testing of the flammable gas detectors should be conducted annually to ensure their performance meets the relevant requirements.
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 calibrations. We are qualified to address fire and explosion prevention issues for our clients.