Xuzhou explosion-proof transformation construction execution standards

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, boast experienced construction teams, and have served major enterprises such as PetroChina, LG, Huanlan Environment, BOE, and Sinovac Biotech, receiving 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, polishing workshops, and plastic production plants, the requirement for explosion-proofing on-site is particularly crucial. Explosion-proof wiring, installation and use of explosion-proof electrical equipment, dust removal systems, architectural layout, and explosion-proof and venting measures must all comply with 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:
Building structure and layout
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, and the roof should be of light construction.
(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 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 must be calculated and ensured to effectively release blast during an explosion.
(4) 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 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
If there is a risk of dust explosion in the equipment within the factory building, it should be located at a higher level of the structure and close to the outer wall.
(2) Equipment with explosive hazards should be located in outdoor 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 transmission mechanisms of the equipment and installations shall comply with the following regulations:
A. The bearings of the process equipment should be dust-proof and sealed. If there is a possibility of overheating, 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 feeding point of the process flow, a magnet, an air separator, or a sieve 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 being generated when stainless steel is abraded against powders of aluminum, zirconium, or other metals containing these elements.
(7) In the event of an explosion, protective parking should be implemented. Several power supply control boxes capable of interlocking with each other should be installed based on the size of the workshop. In emergency situations, the power supply to all motors should be able to be promptly disconnected.
(8) All connections, inspection doors, baffles, and explosion relief cover for process equipment should be sealed tightly.
(9) The equipment housing should be made of non-combustible materials.
(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 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 explosion relief ports should be located near potential ignition sources, ideally at the top or upper part of the containment structure. They must not vent towards flammable and explosive hazardous areas to prevent ignition of others, and they must not vent towards public areas to avoid injury from the explosion.
3. Lightning and static electricity protection
Dust explosion hazard areas should adopt corresponding lightning protection measures in accordance with the relevant provisions of GB50057. When static electricity hazards are present, the following regulations should be adhered to:
(1) All metal equipment, enclosures, metal pipes, brackets, components, parts, etc., generally use anti-static direct grounding. For those that are not convenient or prohibited by the process from direct grounding, grounding can be achieved indirectly through conductive materials or products.
(2) Equipment directly used for containing static powder, such as conveyance pipes (belts) for the powder, should be made of metal or antistatic materials.
All metal pipe connections should be bonded together.
(4) Operators should take anti-static precautions.
(5) Do not use metal conductors or mesh screens in direct contact with high-flowing powders to dissipate static electricity.

Equipment 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 Design of Grounding for AC Electrical Installations" GB/T50065, the following parts that do not require grounding should still be grounded in explosive environments:
1) Non-electrically conductive surfaces, equipment with an alternating current rated voltage of less than 1000V and a direct current rated voltage of less than 1500V, which have normal metal casings not under electrical power.
2) In dry environments, equipment with alternating voltage of 127V or less and direct voltage of 110V or less typically has metal enclosures that are not charged.
3) Equipment installed on a grounded metal structure.
(2) In explosive hazard areas, exposed conductive parts of equipment should be reliably grounded. All equipment within explosive atmosphere zones 0, 20, and 21, as well as all equipment within zones 2 and 22 except for lighting fixtures, should use specialized 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 within explosive atmosphere zones 2 and 22 may use a metallic pipeline system with reliable electrical connections as grounding wire, but not pipes for conveying materials.
(3) In different directions of the slope in the explosive hazard area, the grounding main should be connected to the grounding body at least twice.

Basic Guidelines for Explosion-Proof Electrical Construction (shared by Shenzhen Zhongnuo Inspection Technology Co., Ltd.)
Explosion-proof electrical installation differs from standard electrical installation due to the increased explosion-proof requirements of its environment. In accordance with industry standards, an explosive environment is defined as one where a mixture of gas, vapor, mist, or dust with air can be ignited, causing combustion to spread to the entire unburned mixture. An area where a large number or an expected large number of explosive gas environments or combustible dust environments are present, requiring special preventive measures for the structure, installation, and use of electrical equipment, is called a hazardous area. Explosion-proof electrical installation refers to the work of meeting explosion-proof electrical, conditions, and personnel requirements for construction operations in explosive environments and hazardous areas, which is highly critical.

In accordance with the basic requirements of GB 15577 "Safety Code for Dust Explosion Prevention," for explosion-proof construction and modification in explosive dust environments, the following five main explosion-proof measures can be adopted (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.).
Anti-knock
1. Definition: A controlled explosion technique where the enclosed container, with combustible dust and gaseous oxidizers or air, can withstand the high pressure of a major explosion, preventing the container from being damaged.
2. Objective: By enhancing container wall thickness and improving material, external damage is minimized even in the event of a dust explosion.
3. Basic Requirements:
When producing and handling powdered materials 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 connection parts between various process 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 that is resistant to explosion pressure and impact from explosion pressure should comply with the requirements of GB/T 24626.
Explosion Ventilation
1. Definition: A suppression technology that prevents the destruction of an enclosed package by expelling the high-temperature, high-pressure combustion products and unburned materials generated by an explosion through pre-set weak points in the package, before the explosion pressure reaches the package's limit strength, thus directing the release in a non-hazardous direction.
2. Purpose: To reduce explosion losses by installing explosion relief devices.
3. Methods: Two explosion relief methods are available: flaming and non-flaming.
4. Basic Requirements:
(1) 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. The relief openings should face a safe direction, and their dimensions should comply with the requirements of GB/T 15605.
(2) Equipment with dust explosion hazards installed indoors should vent explosive pressure through pressure relief ducts towards a safe outdoor direction. The pressure relief ducts should be as short and straight as possible, with a cross-sectional area not less than that of the pressure relief opening, and their strength should not be lower than that of the protected equipment container.
(3) Equipment inside the room that cannot vent explosion to the outside via a pressure relief conduit should be equipped with a flameless venting device.
(4) Process equipment with inline piping should be designed to withstand at least 0.1 MPa of internal overpressure.
3. Suppression of Explosion
1. Definition: In the initial stage of an explosion, extinguishing the flame and suppressing (preventing) the development of dust explosion through physical and chemical action.
2. Objective: To pre-detect and extinguish fires, as well as suppress explosions, 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 shall comply with the requirements of GB/T 25445.
Four, Explosion-proof
1. Definition: Technology to prevent the spread of an explosion after it occurs, through physical and chemical actions.
2. Purpose: To prevent flame propagation through pipes or other conduits
3. Basic Requirements:
(3) Equipment and facilities with dust explosion hazards that are interconnected via pipelines should ideally be equipped with explosion suppression devices on the pipelines.
(2) Equipment and facilities with dust explosion hazards that are interconnected through pipelines should be equipped with explosion-proof devices on the pipelines. The shutdown direction should be consistent with the direction of explosion propagation.
Five. Inertization
For processes such as crushing, grinding, drying of powders, and pneumatic conveying through pipelines within sealed containers, inert gases like nitrogen, carbon dioxide, halogenated hydrocarbons, argon, helium, and steam are introduced, as well as inert dusts such as fire extinguishing powder, chemical dry powder, and mineral rock powder. This is to dilute combustible components and reduce the oxygen content in the environment.
Explosion-proof electrical transformation in hazardous areas and on-site explosion-proof construction consulting services - Shenzhen ZhongNuo Inspection Technology Co., Ltd.