Shenzhen ZhongNuo Testing Technology Co., Ltd. is based in South China and specializes in explosion-proof certification and coal safety certification application consulting services, offering one-stop explosion-proof technology consulting services.
Why choose tempered glass for explosion-proof transparent parts?
Transparent components are a crucial material for explosion-proof electrical equipment. When selecting transparent components, customers always ask what material should be used? Can glass be used? Can plastic be used?
Below, Shenzhen Zhongnuo Testing Technology Co., Ltd. explains to you.
GB/T3836.1 explicitly stipulates the thermal shock test for transparent parts, which aims to verify the thermal stability of glass under rapid cooling conditions. Currently, tempered glass is a material that not only meets this requirement but also offers high cost-performance.
To普及， tempered glass forms an even compressive stress layer on the surface after being heated and淬ed, which offsets the tensile stress generated on the surface during rapid cooling. Therefore, qualified tempered glass will have a compressive stress to counteract the stress caused by rapid cooling.

Limitation requirements for surface resistance of non-metallic外壳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 a 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 of the non-metallic material is required to ensure: by selecting the material, the surface resistance meets at least one of the following requirements when measured in accordance with IEC 60079-0 26.13:
At ≤1 GΩ, (505)% relative humidity;
At ≤100 GΩ, (305)% relative humidity.
2. In Class III explosive dust environments, the surface area of non-metallic enclosures of electrical equipment does not need to consider the risk of static electricity if it does not exceed 500 mm². If it exceeds this limit, surface resistance testing is required to verify. The requirements for assessment are the same as those for surface resistance testing limits in Class II gas environments. For fixed installation equipment that cannot meet the surface resistance limits, an "X" can be added after the "explosion-proof" marking, a corresponding warning sign can be placed on the equipment, and the user should be informed in the user manual.

Intrinsically safe equipment has three explosion-proof grades: IA, IB, and IC. These grades are determined based on intrinsic circuit assessment, considering both counted and uncounted faults. IA grade is used in Zones 0, 1, and 2; IB grade is applicable to Zones 1 and 2; IC is only used in Zone 2.
Additionally, intrinsic safety equipment can be used in both mining and non-mining explosive gas and dust environments. It primarily ensures that the surrounding explosive atmosphere cannot be ignited under normal operating conditions and fault conditions by limiting the energy in the circuit. It possesses intrinsic safety, hence the name "intrinsically safe."
If you have more questions about the design and certification of intrinsically safe equipment, Shenzhen Zhongnuo Testing Technology Co., Ltd. is here to further assist you.

What's the difference between corrosion protection level, protection level, and explosion-proof certification level?
Many corporate clients are often confused about the required corrosion resistance, protection, and explosion-proof certification levels for their products.
Due to the products being only one character different in name, both referring to a specific grade of the product, they are similar yet distinct. So, what are the differences between them?
Corrosion prevention involves measures to protect metals prone to rust, thereby extending their service life. Typically, methods such as physical, chemical, and electrochemical corrosion prevention are employed. There are five common levels: indoor F1, F2, and outdoor WF, WF1, and WF2.
Protection rating, commonly known as the IP rating, refers to the dust and water resistance level of the equipment, usually consisting of "IP" followed by two digits.
The explosion-proof grade generally refers to the explosion-proof certification level of the equipment. Each electrical equipment applying for explosion-proof certification will have a corresponding explosion-proof mark, including the explosion-proof type and grade. The explosion-proof grade indicates the explosion-proof area applicable to the product, gas/dust groups, temperature groups, equipment protection level, etc.
Clearly, these are different concepts in different fields. For more information on this topic, feel free to private message us anytime!
Explosion-proof Certification Application Consulting Service - Shenzhen Zhongnuo Testing Technology Co., Ltd.