Shenzhen Zhongnuo Testing Technology Co., Ltd. is based in South China and offers consulting services for explosion-proof construction, safety inspections, renovations, project acceptance, and explosion-proof installations. We are well-versed in explosion-proof construction standards, with experienced construction teams and a wealth of experience. We've served major corporations like PetroChina, LG, Huanlan Environment, BOE, and Sinovac Biotech, earning consistent praise and trust from our clients!
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-proofing on-site is particularly crucial. The installation and use of explosion-proof wiring, electrical equipment, dust removal systems, structural 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 modification cases, Shenzhen ZhongNuo Testing Technology Co., Ltd. has summarized the following points:
1. Structure and layout of buildings
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 single-story, with a lightweight roof structure preferred.
(3) The structural requirements for multi-story buildings are as follows:
A. Multilayer buildings are best suited for frame structures.
B. Buildings without frame structures must be equipped with explosion relief ports that meet the required specifications.
C. If windows or other openings are used as explosion relief ports, they should be calculated and ensured to effectively release the explosion pressure during an explosion.
(4) The requirements for evacuation routes are as follows:
A. The work area should have evacuation routes, and the number and location of the evacuation 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 the process equipment in the factory poses a dust explosion risk, it should be located at a higher level of the building and close to the exterior wall.
(2) 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 flammable dust is present, the transmission mechanisms of the equipment and devices should 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 flow, magnets, pneumatic separators, or sifters capable of removing impurities mixed with the material should be installed to prevent collision between impurities and equipment.
(6) Effective measures should be taken to prevent sparks from occurring when aluminum, zirconium, and other metal powders, or powders containing these metals, come into friction with stainless steel.
(7) Implement protective stopping during an explosion. Several power supply control boxes capable of interlocking with each other should be installed according to the size of the workshop. In emergencies, they should be able to promptly disconnect the power supply to all motors.
(8) Joints, inspection doors, baffles, and explosion relief coverings of process equipment should all be sealed tightly.
(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) When the strength of the process equipment is insufficient to withstand the overpressure generated by internal dust explosion under actual operating conditions, explosion relief openings should be installed, and the size of the openings should comply with the relevant provisions of GB/T15605.
(12) The venting port should be located near potential ignition sources, and it should be as high as possible, preferably at the top or near the top of the containment structure. It must not vent towards flammable and explosive hazard areas to avoid igniting others, and it should not vent towards public spaces to prevent 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 adhered to:
All metal equipment, device enclosures, metal pipes, brackets, components, parts, etc., are generally equipped with antistatic grounding directly. For those that are not convenient or not allowed to be grounded directly due to the process, grounding can be achieved indirectly through conductive materials or products.
(2) Equipment directly used for containing electrostatic powder, such as conveyance pipes (belts) for the powder, should be made of metal or anti-static materials.
(3) All metal pipe connections must be bonded together.
(4) Operators should take anti-static precautions.
(5) Do not use a direct grounding metal conductor or mesh to contact high-speed flowing powder to dissipate static electricity.

General Requirements for Explosion-Proof Workshop Design (Shared by Shenzhen ZhongNuo Inspection & Testing Technology Co., Ltd.)
4.1 Floor, Interior Wall
Areas producing flammable gases heavier than air or vapors of flammable and combustible liquids, as well as Class B production workshops with dust and fiber explosion hazards, should use non-sparking floors. To prevent sparks, the floors can be made of rubber, plastic, rubber mixed with graphite, or asphalt concrete, etc.
Areas of the workshop interior walls where flammable dust may settle should be plastered or painted to create washable (wipeable) interior surfaces.
4.2 Office, Break Room
For personnel safety, do not establish offices or restrooms in Class A or B production facilities where explosions are hazardous. If necessary, such rooms can be located outside the workshop, separated from the workshop by non-combustible walls with a fire resistance of not less than 3.5 hours.
4.3 Electrical Equipment
Electrical equipment in explosion-proof workshops should be selected and installed according to different conditions, using explosion-proof types such as explosion-proof switches, explosion-proof motors, and explosion-proof lighting fixtures, and absolutely avoiding non-explosion-proof types.
4.4 Lightning Protection Equipment
In facilities and workshops prone to explosion, in addition to installing lightning protection devices on the building itself, lightning rods should be installed around the building as required to ensure the building is within the protected range of the entire lightning protection system, thereby preventing accidents caused by lightning strikes.

Installation of electrical wiring in explosive environments shall comply with the following regulations (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
Electrical wiring should be installed in environments with low explosion hazards or far from sources of release, and should comply with the following regulations:
1) When the material is heavier than air, electrical wiring should be installed at a higher level or directly buried; overhead installation should use cable trays; for trench installation, the trench should be filled with sand, and proper drainage measures should be in place.
2) Electrical wiring should be laid outside the walls of buildings or structures that are at risk of explosion.
3) In explosive dust environments, cables should be laid in areas where dust does not accumulate easily and is easy to remove.
(2) Holes in walls or floors between different areas that the electrical cable trench, cable tray, or conduit passes through should be tightly sealed with non-combustible materials.
(3) When laying electrical lines, it is advisable to avoid areas susceptible to mechanical damage, vibration, corrosion, ultraviolet radiation, and potential heat exposure. If avoidance is not possible, preventive measures should be taken.
(4) Tubing wiring can use insulated single-core or multi-core wires without sheath. When the tube contains three or more wires, the total cross-sectional area of the wires, including the insulation, should not exceed 40% of the tube's cross-sectional area. The tube should be made of galvanized steel pipe for low-pressure fluid conveyance. The threaded section of the steel tube connection should be coated with lead oil or phosphating paste. At locations where condensation water may form, a sealed joint for draining condensation water should be installed on the pipeline.
(5) Electrical wiring for pipe routing in explosive gas environments should be properly insulated and sealed, and should comply with the following regulations:
1) During normal operation, the 450mm area around all ignition source enclosures should be sealed off.
2) Steel pipes with a diameter of 50mm or more should be isolated and sealed within 450mm of the incoming junction box.
3) Isolation and sealing should be conducted between adjacent explosive environments, as well as between explosive environments and adjacent other hazardous or non-hazardous environments. During sealing, the inner part of the seal should be filled with a fiber layer or separator as the base, with the effective thickness of the filling not less than the inner diameter of the steel pipe, and not less than 16mm.
4) Connection components for isolation sealing should not be used for wiring connections or branching.
(6) Intermediate joints are strictly prohibited in cable lines within Area 1, and intermediate joints should not be present in Areas 2, 20, and 21.
(7) When terminating cables or wires, if the internal conductors are stranded, the terminals should be connected using a molded terminal or crimped connector. The connection and termination of aluminum-core insulated conductors or cables should be done by crimping, soldering, or brazing. When connecting to equipment (excluding lighting fixtures), a copper-aluminum transition connector should be used.
(8) Overhead power lines must not cross explosive gas environments; the horizontal distance between overhead lines and explosive gas environments should not be less than 1.1 times the height of the tower. In special cases, after effective measures are taken, the distance may be appropriately reduced.

In recent years, with the continuous development of society and the increasing prominence of safety accidents, people's awareness of safety production has been on the rise, and the treatment of potential hazards in hazardous environments is urgently needed.
In various industrial sectors in our country, such as oil, chemicals, ports, coal, and others, there is often a risk of leaks or spills of flammable and explosive gases, liquids, dust, and fibers during production, processing, transportation, and storage. When these substances mix with air, they may form explosive mixtures. Once the concentration of the mixture reaches the explosive range, any ignition source can trigger explosions and severe fires, potentially leading to catastrophic chain reactions. Therefore, equipment used in such hazardous environments must be certified with explosion-proof capabilities. The use of all equipment in explosion-proof environments must be installed and debugged by experienced engineering companies, strictly adhering to the specifications and acceptance standards for explosion-proof construction, before being put into actual production use. This ensures the maximum safety requirements for all stages of the production process.
Explosion-proof electrical改造 for hazardous areas and on-site explosion-proof construction consulting services - Shenzhen ZhongNuo Testing Technology Co., Ltd.