Shenzhen Zhongnuo Inspection & Technology Co., Ltd. is based in South China and offers explosion-proof construction services, safety inspections, renovations, project acceptance, and explosion-proof installation consulting. We are well-versed in explosion-proof construction standards and boast a team with extensive experience. We've served major companies such as PetroChina, LG, Huanlan Environment, BOE Technology Group, 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 important. The installation and use of explosion-proof wiring, electrical equipment, dust extraction systems, architectural layouts, and explosion 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 hazardous dust explosion areas must comply with the relevant standards of GB/T3836, and the electrical design should be executed according to the provisions of GB50058. Explosion-proof electrical equipment should be selected based on the grade of the explosion hazard area and the category, grade, and group of the explosive hazardous substances.
Options for explosion-proof electrical equipment. In addition to dust explosion-proof electrical equipment with dust-tight structures for the 21-zone environment containing combustible non-conductive dust and combustible fibers, dust explosion-proof electrical equipment with dust-tight structures is used in the 20-zone explosive dust environment and other 21-zone explosive dust environments, with electrical equipment selected from different ignition temperature groups based on the varying ignition temperatures of the dust.
(2) Galvanized Welded Steel Pipe for Low-Pressure Fluid Transportation
(3) Connections between steel pipes, steel pipes and electrical equipment, and steel pipe accessories should be made using threaded connections. Soldered pipe sleeves are not permitted, and the following requirements must be met:螺纹 machining should be smooth, complete, and free of corrosion. Electrical grease or conductive anti-rust grease should be applied to the threads. Do not wrap with hemp or insulating tape, nor apply other paints. Steel pipes with a diameter of 25mm or less should have at least 5 threads, and pipes with a diameter of 32mm or more should have at least 6 threads.
(4) Explosion-proof flexible conduits should be installed at the following locations for piping: at the motor's incoming line clamp, where direct connection between the piping and electrical equipment is difficult, and where the piping passes through the expansion joints and settlement joints of the building.
(5) Mobile electrical equipment is not recommended in Zones 20, 21, and 22. If mobile electrical equipment must be used, YC or YCW rubber cables should be selected for the wiring.
AQ3009-2007 "Electrical Explosion Protection Safety Code for Hazardous Areas" classifies dust explosion hazard areas into 20 zones, 21 zones, and 22 zones.
5. Ventilation and Dust Removal
(1) It is recommended 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 settlement within the ductwork.
(4) Baghouse dust collectors should be used, with preference given to external filter type.
(5) Dust collectors should be installed outdoors. If installed indoors, the explosion relief pipe should lead directly outside, be less than 3 meters in length, and a flame arrester should be installed based on 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.
6. Fire Protection
(1) Select the appropriate fire extinguisher based on the physical and chemical properties of the dust.
(2) During extinguishing, prevent dust from being raised to form a dust cloud
(3) If the burning material can generate explosive gas when in contact with water, water should not be used 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. Additionally, explosion-proof tools should be used during maintenance.
(2) Do not use rotating grinding wheels and rotating cutting disks for grinding and cutting if there are no protective measures equivalent to those for open flame operations.
(3) All production workshops and storage rooms where dust may accumulate should be cleaned promptly.
(4) Do not use compressed air for underground blowing.
(5) At the workplace, production staff should not wear close-fitting garments made of synthetic fibers.

Based on the basic requirements of GB 15577 "Safety Regulations for Dust Explosion Prevention," in防爆construction and modification in explosive dust environments, the following five major explosion prevention measures can be primarily adopted (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.).
Anti-knock
1. Definition: A explosion suppression technique that allows the containment to withstand the high pressure of an explosion when flammable dust and gaseous oxidizers or air are present inside.
2. Objective: By enhancing the container wall thickness and improving the material, external damage can be minimized even in the event of a dust explosion.
3. Basic Requirements:
When producing and handling powders that can cause explosions, if there is no explosion suppression device and no pressure relief measures, all process equipment should be designed to be explosion-proof and capable of withstanding the overpressure generated by internal explosions without bursting.
(2) The connecting parts between various processing equipment (such as pipes, flanges, etc.) should have the same strength as the equipment itself. For connections between high-strength and low-strength equipment, explosion-proof devices should be installed.
(3) Equipment for resistance to explosive pressure and impact of explosive pressure should comply with the requirements of GB/T 24626.
Explosion Relief
1. Definition: A fire suppression technology that, during an explosion within the containment structure, allows the high temperature, high-pressure combustion products, and unburned materials generated by the explosion to be discharged through pre-set weak points to a safe direction before the explosion pressure reaches the containment structure's limiting strength, thus preventing the containment structure from being destroyed.
2. Objective: To reduce explosion losses by installing explosion relief devices.
3. Methods: Two explosion relief methods are available, flammable and non-flammable.
4. Basic Requirements:
(1) If the strength of the process equipment is insufficient to withstand the overpressure caused by internal dust explosion under actual operating conditions, a venting port should be set. The venting port should face a safe direction, and its size should comply with the requirements of GB/T 15605.
(2) Indoor dust explosion hazard process equipment should be vented to a safe outdoor direction through pressure relief conduits. The conduits should be as short and straight as possible, with a cross-sectional area not less than that of the relief opening, and their strength should not be less than the strength of the container protecting the equipment.
(3) For equipment inside the room that cannot vent to the outside via a pressure relief conduit, flameless explosion venting caps should be installed.
(4) Process equipment with inline piping shall be designed to withstand at least 0.1 MPa of internal overpressure.
Section 3: Explosion Suppression
1. Definition: At the initial stage of an explosion, extinguishing the flame and suppressing (preventing) the development of dust explosion through physical and chemical actions.
2. Purpose: To detect and extinguish fires, and suppress explosions in advance by setting up explosion suppression devices.
3. Basic Requirements:
Process equipment with a risk of dust explosion should be protected with explosion suppression devices.
(2) If a monitored explosion suppression device is used, it should comply with the requirements of GB/T 18154.
(3) Explosion suppression system design and application should comply with the requirements of GB/T 25445.
Four, Explosion-proof
1. Definition: Technology that prevents the propagation of an explosion after its occurrence through physical and chemical actions.
2. Purpose: To prevent the spread of flames through pipes or other passages
3. Basic Requirements:
(3) Equipment and facilities with dust explosion hazards that are interconnected through pipelines should be equipped with explosion-proof devices on the pipelines.
(2) Equipment and facilities with dust explosion hazards that are interconnected by pipelines should be equipped with explosion-proof devices on the pipelines. The shutdown direction should align with the direction of explosion propagation.
Five: Inertizing
For processes such as crushing, grinding, drying of powders, and pneumatic conveying through pipelines in sealed containers, inert gases like nitrogen, carbon dioxide, halogenated hydrocarbons, argon, helium, and steam, as well as inert dusts such as fire extinguishing powder, chemical dry powder, and mineral rock powder are introduced. This is to dilute combustible components and reduce the oxygen content in the environment.

As the world's energy and chemical industries develop, construction in explosive hazardous environments is becoming increasingly widespread, and the prevention and acceptance of such environments are becoming more crucial.
Especially in flammable dust environments, such as plastic factories, feed/food/grain processing plants, metal polishing workshops, papermaking/forestry wood powder/fiber dust factories, and so on, the number of projects involving explosion-proof installation, design, and renovations is also increasing.
Whether it's large-scale explosion-proofing or local explosion-proofing, if there are hidden dangers in product quality or installation/renovation quality.
Our personnel and property security face significant threats, hence we must meticulously control the quality at each production stage to ensure the reliability and safety of explosion-proof installations and renovations.
Shenzhen ZhongNuo Testing Technology Co., Ltd. offers explosion-proof construction and modification consulting services, boasting a wealth of qualifications and case studies, it's worth considering!

Basic Explosion-Proof Design Standards for Hazardous Areas (Shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. First, conduct an overall explosion protection design
2. Directed release of explosive energy. Around the explosion source, comprehensively utilize anti-explosion and venting technology, setting anti-explosion walls and windows in the direction of high population density, office areas, and critical equipment; and venting walls and windows in directions with low human traffic and no critical equipment.
3. Establish safe distances. Minimize the placement of office areas, residential zones, and critical equipment areas within the range less than the safe distance unless necessary; if set, implement necessary explosion-proof measures.
4. Conversion of non-blast-resistant buildings to blast-resistant structures. Within the range of less than the safe distance, blast resistance assessment of the buildings should be conducted, and reinforcement for buildings not meeting blast resistance requirements should be carried out: to prevent building collapse; to prevent the fracturing of brittle materials such as bricks, concrete, glass, etc., resulting in debris.
5. Place explosion-proof shelters in hazardous blast zones.
Explosion-proof electrical renovations and on-site explosion-proof construction consulting services for hazardous areas - Shenzhen Zhongnuo Testing Technology Co., Ltd.