Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China and specializes in explosion-proof certification and coal mine safety certification application consulting services, offering a one-stop explosion-proof technology consulting service.
What do the 0, 1, and 2 zones in explosion-proof certification mean?
This is the classification of explosion-proof zones in explosive gas environments, divided into Zone 0, Zone 1, and Zone 2.
Zone 0: Areas where explosive gas mixtures are continuously present or exist for extended periods (over 1000 hours per year).
Zone 1: Areas where explosive gas mixtures may normally be present.
Zone 2: Under normal circumstances, explosive gas mixtures are unlikely to occur, only in locations where they may briefly exist under abnormal conditions (less than 10h/y).
Division of explosion-proof areas in explosive dust environments, categorized into Zones 20, 21, and 22.

Application Process for Explosion-Proof Certification at Shenzhen Zhongnuo Testing Technology Co., Ltd.
1. Conduct product evaluation and provide an initial quote for the requested product. Evaluate the product using the company's product specifications, electrical schematics, and component list, determine the suitable type of explosion-proof certification for the product, and offer an initial quote.
2. Provide samples for testing at the lab; the quantity of samples required varies depending on the product category.
3. Provide materials list review
Application documents, including applicant's information and other relevant materials
(2) Technical documents, including the submitted technical materials from the company such as corporate standards or technical requirements, product drawings, user manuals, etc.
A. Corporate Standards/Technical Requirements: The corporate standards/technical requirements for products should be written in the prescribed format, including not only performance requirements but also relevant content regarding explosion-proof aspects: such as basic parameters, explosion-proof markings, operating environmental conditions, explosion-proof performance requirements, relevant tests for explosion-proof performance, and markings related to explosion-proof.
B. Product Drawings: When an enterprise applies for a防爆 certification for intrinsic safety electrical equipment, it should provide assembly drawings, circuit diagrams, printed circuit board diagrams, silk screen diagrams, component material lists, and label diagrams, etc. For non-intrinsic safety electrical equipment, the technical documents submitted for inspection should include drawings that reflect the sample's explosion-proof performance (including assembly drawings and component drawings). If the overall drawing can clearly indicate the product's explosion-proof parameters and structure, only the overall drawing needs to be submitted for inspection.
C. Instruction Manual - The instruction manual should include basic parameters, explosion-proof markings, product outline diagram, installation, maintenance, order instructions, and clear notices to the user regarding the precautions to ensure the product's explosion-proof performance during installation and use.
D. Other Information: For products with adhesive bonding or casting, provide the型号 names, performance descriptions, and relevant process documents for the adhesive and casting agents. For plastic shell products, provide the material and corresponding performance documents.
4. Certificate Issuance

Limitation requirements for surface resistance of non-metallic enclosures of explosion-proof equipment
In hazardous areas with explosive dust or gases/vapors, such as coal powder and flour, static electricity can cause fires or explosions, posing significant danger. Therefore, it is advisable to minimize the use of insulating materials in explosive hazard areas. When selecting electrical insulating materials, consider maintaining low insulation resistance to prevent discharge when non-metallic components come into contact with charged components. For non-metallic insulating materials, the antistatic capability of the equipment can be assessed by measuring the surface resistance of the equipment's housing.
Surface resistance, measured in ohms (Ω), refers to the resistance between two electrical contacts on the measuring surface.
In accordance with the requirements of the IEC 60079 series standards:
1. In Class II explosive gas environments, when the surface area of a non-metallic housing of electrical equipment exceeds a certain limit value (as shown in Table 1), a surface resistance test must be conducted on the non-metallic material to ensure that: by selecting the material, the surface resistance meets at least one of the following requirements when measured according to IEC 60079-0 26.13:
At ≤1 GΩ, (505)% relative humidity;
At ≤100 GΩ, (305)% relative humidity.
2. In environments with Class III explosive dust, if the surface area of the non-metallic housing of electrical equipment does not exceed 500 mm2, the risk of static electricity can be disregarded; if it exceeds this limit, a surface resistance test must be conducted. The assessment requirements are the same as those for the surface resistance test limit in Class II gas environments. For fixed-installation equipment that cannot meet the surface resistance limit, an "X" can be added after the "Explosion-proof" symbol, a corresponding warning sign should be placed on the equipment, and the user should be informed in the user manual.

What are the requirements for applying for an explosion-proof certificate for a gas detector?
Gas detectors are a common type of explosion-proof product, with common types including intrinsically safe, flameproof, and flameproof/intrinsically safe, etc.
The type of explosion-proof design to adopt depends on the product's structure, installation method, and usage location, among other factors.
Portable and handheld models are recommended to obtain intrinsically safe explosion-proof certificates; they are quite lightweight.
Additionally, for gas detectors used in Zone 0, they can only be intrinsically safe IA explosion-proof grade.
Consider intrinsically safe circuit design, housing material, and battery temperature rise tests for intrinsically safe products.
Fixed installations can be made explosion-proof. Explosion-proof products are rather bulky, mainly achieving explosion prevention through the explosion-proof housing.
Even if internal components generate sparks, the explosion can be blocked from spreading due to the explosion-proof housing.
On the other hand, the housing can also prevent external explosion sparks from entering the internal components of the equipment.
Of course, some gas detectors can't simply achieve explosion-proof performance with intrinsic safety or flameproof designs.
At this point, consider the explosion-proof and intrinsically safe composite explosion-proof types.
ZhongNuo Inspection has obtained domestic and international explosion-proof certifications for gas detectors, alarms, transmitters, and other instruments and meters for our clients.
We have extensive experience and case studies. Feel free to DM us for a discussion!
Explosion-proof Certification Application Consulting Service - Shenzhen Zhongnuo Testing Technology Co., Ltd.