Ex-proof certification acquisition process Shenzhen ZhongNuo Inspection

Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China, specializing in explosion-proof certification and coal mine safety certification application consulting services, offering a one-stop explosion-proof technology consulting service.
Division of flammable and explosive gas environment areas
Zone 0: In normal circumstances, areas where flammable and explosive gas mixtures occur continuously, frequently, or over a long period, such as certain parts of oil drilling platforms. The presence of hazardous gases typically lasts ≥1000 hours/year.
Zone 1: In normal circumstances, areas where combustible and explosive gas mixtures may occur, such as non-mining areas of coal mines, enclosed petrochemical areas (with ventilation openings), etc. The presence of hazardous gases in this area typically lasts between 10-1000 hours per year.
Zone 2: Under normal circumstances, flammable and explosive gas mixtures are unlikely to occur, and if they do, it is only occasionally and for short periods, such as in non-enclosed areas of oil and petrochemical industries (outdoor areas). The presence of hazardous gases typically lasts ≤10 hours/year.
Division of flammable and explosive dust environment areas
Zone 20: Areas or enclosures where combustible dust is continuously present or frequently present during normal operation, in quantities sufficient to form a mixture of combustible dust and air and/or to form an uncontrolled and thick layer of dust. Examples include certain dust storage containers and silos. Presence time of combustible dust ≥ 1000 hours/year.
Zone 21: Areas where mixtures of combustible dust and air may form explosive concentrations during normal operation. For example, areas outside of dust containers under specific conditions. The presence of combustible dust ranges between 10-1000 hours/year.
Zone 22: Combustible dust-air mixtures are generally present under normal operating conditions; combustible dusts occasionally appear only under abnormal conditions and are only transiently present. For example, at the exhaust outlet of a dust collector bag filter vent during a fault. The presence of combustible dust is ≤10 hours/year.
Note that the classification of hazardous areas should take into account factors such as the quantity of flammable and explosive dust, explosion limits, and ventilation conditions. Additionally, under specific conditions, they may be designated as non-hazardous areas.

Explosion-proof electrical equipment refers to electrical devices used in environments containing flammable and explosive materials. It is designed with specific explosion-proof measures to prevent sparks, arcs, or high temperatures from the electrical equipment itself from causing accidents.
Here are some fundamental knowledge points about explosion-proof electrical equipment:
Flammable and explosive substances are classified and grouped. Flammable gases are categorized based on their Maximum Experimental Safe Gap (MESG) or Minimum Ignition Current Ratio (MICR), and divided into IIA, IIB, and IIC groups.
Combustible dust is categorized by its conductivity into Conductive Dust IIIC, Non-Conductive Dust IIIB, and Combustible Fibers IIIA.
Hazardous Area Classification
Based on the physical state of flammable and explosive substances, they are categorized into two types: gas hazardous areas and dust hazardous areas.
Gas hazardous areas are classified into three explosion-proof zones—Zone 0, Zone 1, and Zone 2—based on the frequency and duration of the gas environment occurrence.
Zone 0: Normally, locations where gas mixtures are continuously present, frequently occur, or exist for extended periods, such as certain areas of oil drilling platforms. The presence of hazardous gases typically lasts ≥1000 hours/year.
Zone 1: Normally, locations where gas mixtures may occur, such as non-mining surfaces of coal mines, enclosed areas of oil and petrochemical industries (with ventilation openings). The presence of hazardous gases in this zone typically lasts between 10 to 1000 hours per year.
Zone 2: Under normal conditions, gas mixtures are unlikely to occur, appearing only occasionally and for short periods during abnormal situations, such as in non-enclosed oil and petrochemical areas (outdoor). The presence of hazardous gases typically lasts ≤10 hours/year.
Dust hazardous areas are divided into three explosion-proof zones—20, 21, and 22—based on the frequency and duration of occurrence of combustible dust/air mixtures, as well as the thickness of the dust layer.
Zone 20: Areas or containers where combustible dust is continuously or frequently present during normal operation, in quantities sufficient to form a combustible dust-air mixture and/or to form an uncontrolled and thick dust layer. Examples include certain dust containers, storage tanks, etc. Presence of combustible dust for ≥ 1000 hours/year.
Area 21: Locations where mixtures of combustible dust and air may reach flammable concentrations during normal operation. Examples include areas outside of dust containers under specific conditions. The presence of combustible dust ranges between 10-1000 hours/year.
Zone 22: Combustible dust-air mixtures are generally present under normal operation, while occasional occurrences of combustible dust are only short-term and under abnormal conditions, such as at the exhaust outlet of a dust collector bag filter during a fault. The presence of combustible dust is ≤10 hours/year.
Explosion-proof electrical equipment selection
Selection principles prioritize safety and reliability, as well as economic rationality. Selection should be based on the level of the hazardous area, the type, grade, and group of hazardous substances.
For example, the explosion-proof type "d" places components that can generate spark arcs during normal operation within an explosion-proof housing. This housing can withstand internal pressure without damage and ensures that the flame gases within are transmitted through gaps with reduced energy, which is insufficient to ignite gases outside the housing.
Increased safety type "e" improves the safety reliability of equipment by taking certain measures to reduce the likelihood of sparks, arcs, and dangerous temperatures; intrinsic safety type "i" limits the energy released by the part of the circuit in explosive hazardous areas to a certain value, in order to achieve the purpose of explosion prevention.
Please refer to relevant standards for specific selection, such as GB/T 3836, AQ3009-2007, etc.
Electrical wiring installation
Installation methods for electrical wiring in flammable and explosive environments can be categorized into cable wiring and conduit wiring methods.
Electrical wiring should be installed in areas of lower risk or at a greater distance from the source of release, avoiding locations prone to mechanical damage, vibration, corrosion, dust accumulation, and those with hazardous temperatures.
When unavoidable, take preventive measures. For example, use low-voltage cables or insulated conductors.
Equipment inspection and maintenance
To minimize the ignition hazard of electrical equipment in hazardous areas, initial inspections should be conducted during the handover acceptance of the engineering construction before the equipment is put into operation.
To ensure electrical equipment remains in good condition for long-term use in hazardous areas, continuous supervision and regular inspections should be conducted.
These inspections and maintenance should be conducted by qualified institutions meeting the prescribed criteria. They must undergo business training including the general principles of explosion-proof types, installation practices, relevant regulations and procedures, as well as the classification of hazardous areas. They should also receive appropriate continuing education or regular training, and possess relevant experience and trained qualifications.
Regular inspections should be entrusted to safety production testing and inspection agencies with explosion-proof qualifications, with intervals generally not exceeding 3 years. Enterprises should take corrective actions promptly based on the inspection results and file the inspection report and the rectification status with the safety production supervision and management department.
Flameproof Symbol Meaning
The explosion-proof marking typically includes the general explosion-proof symbol "Ex" and other letters and numbers indicating the type of explosion-proof, operating environment, temperature group, etc.
Ex db ib IIC T4 Gb防爆标志
This is a composite explosion-proof marking.
Ex indicates explosion-proof; explosion-proof equipment must be marked with the Ex symbol.
db ib refers to the explosion-proof protection type of the equipment, meaning it is a combination of flameproof and intrinsically safe.
IIC refers to equipment suitability for IIC classification flammable and explosive gas environments (representative gases include those).
T4 is the temperature category, indicating that the equipment's high surface temperature does not exceed 135°C.
Gb refers to the equipment protection level, applicable to Zones 1 and 2.
When using explosion-proof electrical equipment in hazardous environments, it is mandatory to strictly adhere to relevant standards and regulations to ensure production. Simultaneously, installation, inspection, and maintenance should be carried out by personnel to ensure the continuous effectiveness of the equipment's explosion-proof performance. For specific installation and use of explosion-proof electrical equipment, it is recommended to refer to relevant standards, industry specifications, and the equipment manufacturer's manual.

Is ATEX certification the same as explosion-proof certification? What are the differences between them?
Explosion-proof certification refers to a type of safety certification for equipment and products used in explosive hazard areas.
To meet the requirements of explosion-proof certification standards, certain measures must be taken to achieve what we refer to as explosion-proof protection types.
Common explosion-proof protection types include intrinsic safety, flameproof, positive pressure, and increased safety, etc.
Clearly, intrinsically safe is just one type of explosion-proof protection.
Different explosion-proof protection types have varying design requirements for products.
Intrinsically safe is a type of explosion-proof protection that limits electrical energy, ensuring that even in the event of a fault, the energy produced is not sufficient to ignite the surrounding explosive environment.
Therefore, intrinsic safety requirements for electrical equipment include limitations on current, voltage, capacitance, inductance, etc., and are generally applicable to low-power devices.
Additionally, specific requirements are in place for the power supply method of intrinsically safe equipment, the material of the housing, and wireless transmission.
As a third-party consulting agency specializing in explosion-proof certification for many years, CN Testing has dedicated in-house engineers for intrinsically safe circuit and structural design. We offer technical consultation for explosion-proof circuit design, illustration, and rectification, and have extensive experience in designing and obtaining certifications for intrinsically safe ia, ib, and ic classifications.
If you require certifications in this area, feel free to DM us!

What documents are required for applying for explosion-proof certification?
1. Product Drawings and Documents: When an enterprise applies for a certification of explosion-proof compliance for intrinsic safety electrical equipment, it should provide assembly drawings, circuit diagrams, printed circuit board layouts, silk screen drawings, material lists for components, and label diagrams, among others. For non-intrinsic safety electrical equipment, the technical documents submitted for testing should include drawings that reflect the explosion-proof performance of the sample (including assembly and component drawings). If the assembly drawing clearly indicates the explosion-proof parameters and structure of the product, only the assembly drawing needs to be submitted for testing.
2. Technical Documents: Including corporate standards/technical requirements. The corporate standards/technical requirements for products should be written in the prescribed format, and their content should include not only performance requirements of the products but also related aspects of explosion-proof: such as basic parameters, explosion-proof markings, environmental conditions of use, explosion-proof performance requirements, relevant tests for explosion-proof performance, and markings related to explosion-proof.
3. Additional Information: For products with adhesive bonding or casting, provide the model names, performance descriptions, and relevant process documents for the adhesives and casting agents. For plastic encased products, include the material of the plastic and corresponding performance documents. Battery-powered products require the provision of relevant battery specifications.
Explosion-proof Certification Application Consulting Service - Shenzhen Zhongnuo Testing Technology Co., Ltd.