Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China, offering on-site explosion-proof construction, safety inspections, renovations, project acceptance, and explosion-proof installation consulting services. We are well-versed in explosion-proof construction standards, with experienced construction teams and a wealth of experience. We've served major corporations such as PetroChina, LG, Hanlan Environment, BOE Technology Group, and Sinovac Biotech, receiving consistent praise and trust from our clients!
Shenzhen Zhongnuo Testing Technology Co., Ltd. offers explosion-proof construction service in the field of:
Explosive gas environments and hazardous areas with explosive or flammable dust are present in numerous industries and sectors, including petrochemicals, metal smelting, fine chemicals, petrochemical ground facilities (such as gas stations, filling stations, petrochemical warehousing and transportation), new energy, special equipment, nuclear power, tunnels, grain processing, wood processing, metal component manufacturing, environmental protection engineering, and more. Ensuring the explosion-proof safety of these hazardous areas safeguards our and the national economy's development.

Basic Dust Explosion Proof Construction Standards
In facilities where explosive dust is present, such as flour mills, feed factories, grinding workshops, and plastic production plants, the requirement for explosion-proof measures on-site is particularly crucial. The installation and use of explosion-proof wiring, electrical equipment, dust removal systems, architectural layout, and explosion-proof venting must all comply with the relevant dust explosion-proof standards. Based on a wealth of explosion-proof electrical construction and retrofitting cases, Shenzhen Zhongnuo Testing Technology Co., Ltd. has summarized the following points:
1. Structure and layout of the building
Process equipment with a dust explosion hazard or buildings (structures) containing combustible dust should be separated from other buildings (structures), and their fire protection distances should comply with the relevant provisions of GB50016.
(2) The building should be a single-story structure, with a lightweight roof design preferred.
(3) The structural requirements for multi-story buildings are as follows:
A. Multi-story buildings are best suited for frame structures.
B. Buildings without frame structures must have explosion relief openings installed on the walls in compliance with requirements.
C. If windows or other openings are used as blast relief ports, they should be calculated and ensured to effectively release the explosion pressure during an explosion.
(4) Evacuation route requirements are as follows:
The work area should have evacuation routes, and the number and location of these routes should comply with the relevant provisions of GB50016.
B. The door should open outward and no threshold should be installed.
C. Detailed road signs and emergency lighting should be set up for evacuation routes.
2. Process Equipment
(1) If there is a risk of dust explosion in the workshop, such equipment should be located on a higher floor of the building and close to the exterior wall.
(2) Process equipment with explosive hazards should be located in outdoor open areas outside of buildings.
(3) Equipment or devices that come into direct contact with dust (such as light sources, heating sources, etc.) should have surface temperatures below the respective dust's low ignition temperature.
(4) In areas where combustible dust is present, the drive mechanisms of the equipment and installations shall comply with the following regulations:
The bearings of the process equipment should be dust-proof and sealed. If overheating is possible, a detector capable of continuously monitoring the bearing temperature should be installed.
B. Belt drive is not recommended. If belt drive is used, a speed difference sensor and an automatic anti-slip protection device should be installed. In case of sliding friction, the protection device should ensure automatic shutdown.
(5) At the feed point of the process, a magnet, an air separator, or a sieve capable of removing impurities mixed in the material should be installed to prevent collision between impurities and equipment.
(6) Effective measures should be taken to prevent sparks from being generated when stainless steel is abraded with metal powders such as aluminum, zirconium, or powders containing these metals.
(7) Implement protective stoppage upon explosion. Depending on the size of the workshop, install several power supply control boxes capable of interlocking with each other. In emergency situations, they should be able to promptly cut off the power supply to all motors.
(8) All joints, inspection doors, baffles, and explosion relief cover plates of the process equipment should be tightly sealed.
(9) The equipment housing should be made of non-flammable material
(10) The moving parts of the equipment should operate smoothly without any scraping, bumping, jamming, or rubbing.
(11) If the strength of the process equipment is insufficient to withstand the overpressure generated by internal dust explosion under actual working conditions, explosion relief ports should be installed, and the size of the relief ports should comply with the relevant provisions of GB/T15605.
(12) The venting port should be located near potential ignition sources and should be as close to the top or upper part of the containment structure as possible. It must not vent towards flammable and explosive hazardous areas to prevent igniting others, and it must not vent towards public areas to avoid causing injury from venting explosions.
3. Lightning and static electricity protection
Dust explosion hazard areas should adopt lightning protection measures in accordance with the relevant provisions of GB50057. When static electricity hazards are present, the following regulations should be observed:
(1) All metal equipment, enclosures, metal pipes, brackets, components, parts, etc., are generally electrostatically grounded directly. For those that are not convenient or not allowed to be grounded directly due to the process, indirect grounding can be achieved through conductive materials or products.
(2) Containers and pipes (belts) used directly for containing electrostatic powder should be made of metal or anti-static materials.
(3) All metal pipe connections should be bonded together.
(4) Operators should take anti-static precautions.
(5) Do not use direct grounding metal conductors or mesh screens to contact high-speed flowing powders for static electricity dissipation.

Equipment protection grounding in explosive environments shall comply with the following specifications (shared by Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
In accordance with the relevant provisions of the current standard "Code for Grounding Design of AC Electrical Installations" GB/T50065, the following parts that do not require grounding should still be grounded in explosive environments:
1) Equipment with a normal, non-electrified metal housing, where the alternating current rated voltage is below 1000V and the direct current rated voltage is below 1500V, in locations with poor electrical conductivity.
2) In dry conditions, equipment with alternating current rated voltage of 127V or less and direct current voltage of 110V or less typically has a non-electrified metal housing.
3) Equipment installed on a grounded metal structure.
(2) In explosive hazardous environments, the exposed conductive parts of the equipment should be reliably grounded. All equipment within explosive zones 1, 20, and 21, as well as other equipment within explosive zones 2 and 22 excluding lighting fixtures, should use dedicated grounding wires. If the grounding wire is installed in the same protective conduit as the phase wire, it should have insulation equal to that of the phase wire. Lighting fixtures within explosive zones 2 and 22 can utilize a metal pipeline system with a reliable electrical connection as a grounding wire, but not the pipeline for conveying substances.
(3) In different directions of the slope in the explosion hazard area, the grounding main should be connected to the grounding body at least twice.

In recent years, with the continuous development of society and the frequent occurrence of safety accidents, people's awareness of safety production has been increasingly enhanced, and the governance of potential hazards in dangerous environments is urgently needed.
In numerous industrial sectors in our country, such as oil, chemicals, ports, coal, and more, leaks or spills of flammable and explosive gases, liquids, dust, and fibers may occur during various stages including production, processing, transportation, and storage. When these substances mix with air, they can form explosive mixtures. If the concentration of the mixture reaches the explosive range, a spark can trigger explosions and severe fires, potentially leading to massive chain reactions. Therefore, equipment used in such hazardous environments must be certified explosion-proof products with certified safety features. The use of all explosion-proof equipment must be installed and adjusted by experienced engineering companies, strictly adhering to the specifications and acceptance standards for explosion-proof construction. Only then can the safety requirements of all stages in the production process be maximally guaranteed.
Explosion-proof electrical retrofitting and on-site explosion-proof construction consulting services for hazardous areas — Shenzhen Zhongnuo Testing Technology Co., Ltd.