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 practical experience. We have served major corporations such as PetroChina, LG, Hanlan Environment, BOE Technology Group, and Sinovac Biotech, receiving consistent praise and trust from our clients!
Basic Safety Electrical Installation Standards (Shared by Shenzhen ZhongNuo Inspection Technology Co., Ltd.)
Explosion-proof electrical construction differs from standard electrical construction due to the increased explosion-proof requirements of its environment. Based on industry standards, an environment is considered explosive when air is mixed with gases, vapors, thin fogs, or dust, and ignition causes combustion to spread to the entire unburned mixture. An area where a large number of explosive gas environments or flammable dust environments are present or expected, necessitating special preventive measures for electrical equipment design, installation, and use, is termed a hazardous area. Explosion-proof electrical construction refers to a task that meets explosion-proof electrical, environmental, and personnel requirements, conducted in explosive environments and hazardous areas, with strong emphasis on safety.

As the world's energy and chemical industries develop, construction in explosive hazardous environments is becoming increasingly widespread, and the prevention and acceptance of explosive environments are becoming increasingly important.
Especially in flammable dust environments, such as plastic factories, feed/food/grain processing plants, metal polishing workshops, and paper/milling wood powder/fiber dust factories, the number of projects involving explosion-proof installations, designs, and renovations is also increasing.
In either large-scale or localized explosion-proof scenarios, if there are hidden dangers in product quality or installation/renovation quality.
Our personal and property safety is greatly threatened, so we must control the quality at every stage to ensure the reliability and safety of explosion-proof installations and renovations.
Shenzhen ZhongNuo Inspection Technology Co., Ltd. offers explosion-proof construction and retrofitting consultation services, boasts rich qualifications and case studies, highly recommended!

Equipment protection grounding in explosive environments shall comply with the following regulations (shared by Shenzhen ZhongNuo Testing 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) Non-electrically conducting surfaces, metal enclosures of equipment that are normally not energized and have an alternating current rated voltage of less than 1000V and a direct current rated voltage of less than 1500V.
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 metal enclosure that is not charged.
3) Equipment installed on a grounded metal structure.
(2) In explosive hazard 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 in 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 must have insulation equal to that of the phase wire. Lighting fixtures in zones 2 and 22 can utilize a metal piping system with a reliable electrical connection as a grounding wire, but not the piping for conveying substances.
(3) In different directions of the slope in the explosion hazard area, the grounding main should connect to the grounding body at least twice.

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 important. The installation and use of explosion-proof wiring, electrical equipment, dust removal systems, architectural layouts, 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:
4. Explosion-proof electrical equipment
Electrical equipment used in dust explosion hazard areas must comply with the relevant standards of GB/T3836. The power design should be executed in accordance with the provisions of GB50058. Explosion-proof electrical equipment should be selected based on the level of explosion hazard area, as well as the category, level, and group of explosive hazardous substances.
Options for explosion-proof electrical equipment. In addition to dust explosion-proof electrical equipment with dust-tight construction for environments in Zone 21 with combustible non-conductive dust and combustible fibers, dust explosion-proof electrical equipment with dust-tight construction is used in Zone 20 for explosive dust environments and other explosive dust environments in Zone 21. The electrical equipment is selected based on different ignition temperature groups according to the varying ignition temperatures of the dust.
(2) Low-pressure fluid transmission galvanized焊接 steel pipes for conduit tubing
(3) Connections between steel pipes, steel pipes and electrical equipment, and steel pipe accessories should be made using threaded connections. Soldering with sleeves is prohibited, and the following requirements must be met: the threading should be smooth, complete, and free of rust. Electrical compound grease or conductive anti-rust grease should be applied to the threads. Do not wrap the threads with hemp or insulating tape, nor apply other paints. For steel pipes with a diameter of 25mm or less, there should be at least 5 threads, and for steel pipes with a diameter of 32mm or more, there should be at least 6 threads.
(4) Explosion-proof flexible conduit should be installed at the following locations for piping of steel pipes: at the motor's incoming line clamp, where direct connection between the steel pipe and electrical equipment is difficult, and where the piping passes through the expansion joints or settlement joints of the building.
(5) It is not advisable to use portable electrical equipment in Zones 20, 21, and 22. If portable electrical equipment must be used, YC or YCW rubber cables should be selected for the wiring.
AQ3009-2007 "Electrical Explosion Protection Safety Regulations for Hazardous Areas" classifies dust explosion areas into 20 zones, 21 zones, and 22 zones.
Ventilation and dust removal
(1) It is advisable to set up a dust removal system with opposing sections according to the process.
(2) All dust-generating points should be equipped with dust collectors.
(3) There should be no dust settling in the ductwork.
(4) Baghouse dust collectors should be used, with preference given to external filter style.
(5) The dust collector should be installed outdoors. If installed indoors, the explosion relief pipe should directly lead outside, with a length less than 3 meters, and a flame arrester should be set according to the dust properties.
(6) It is advisable to install isolation valves at the inlet and outlet of the dust collector and set up a temperature monitoring device.
(7) Pulse-jet bag dust collector should use nitrogen, carbon dioxide, or other inert gases as the cleaning gas source.
Fire Protection
(1) Select the appropriate fire extinguisher based on the physical and chemical properties of the dust.
(2) During fire extinguishing, prevent dust from rising to form a dust cloud.
(3) If the burning material reacts with water to produce explosive gases, do not use water to extinguish the fire.
7. Job Safety
When dust clouds can be ignited by sparks produced from collisions, measures should be taken to prevent collisions from occurring. Moreover, explosion-proof tools should be used during maintenance.
(2) Do not use rotating grinding wheels and rotating cutting disks for grinding and cutting without equivalent protection measures to open flame operations.
(3) All production workshops and storage rooms where dust may accumulate should be swept promptly.
(4) Do not use compressed air for downhole blowing.
(5) At the workplace, production personnel should not wear close-fitting garments made of synthetic fibers.
Explosion-proof electrical改造 for hazardous areas and on-site explosion-proof construction consulting services - Shenzhen Zhongnuo Testing Technology Co., Ltd.