Shenzhen ZhongNuo Testing Technology Co., Ltd. specializes in the calibration, certification, and measurement services for gas alarms, flammable gas detectors, toxic and harmful gas detectors, and other equipment at various locations. We provide nationwide services to address various electrical safety and explosion-proof fire prevention issues for clients, promoting safe production.
Standard for verification and calibration of combustible and toxic gas detectors:
GB/T 50493-2019 "Design Standard for Detection and Alarm Systems of Combustible Gases and Toxic Gases in Petroleum and Chemical Industry"
GB12358-2006 General Technical Requirements for Environmental Gas Detection and Alarm Instruments in Workplace
JJG 693-2011 "Regulation for Calibration of Combustible Gas Detectors"

Power-on inspection
After power on, the instrument should operate normally with clear and complete display. Check the alarm function and alarm trigger values.
Alarm function and alarm action value check
The instrument's sound and light alarm should function normally. Insulation resistance
Insulation resistance for instruments using AC power should not be less than 20MΩ.

The principle of instrument detection mainly includes catalytic combustion, infrared absorption, and thermal conductivity types. The sampling methods are diffusion and aspiration. The instrument is mainly composed of detection elements, amplification circuits, alarm systems, and displays, used for monitoring the concentration of combustible gases in the environment.

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 glossy, with even paint and plating coatings, free of peeling and rusting.
The instrument's connections are reliable, and all dials or buttons should operate and control normally.
Logos and Symbols
Instrument name, model, manufacturer's name, manufacturing date, serial number, explosion-proof markings and numbers, as well as the manufacturing metrological instrument license mark and number for domestic instruments should be clear.
Shenzhen ZhongNuo Inspection & Technology Co., Ltd. is an independent third-party institution specializing in electrical safety, electrical explosion prevention, gas alarms, and toxic gas detectors for regular verification, measurement, and calibration services. We hold the资质 to address fire and explosion prevention issues for our clients.