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!
Shenzhen Zhongnuo Testing Technology Co., Ltd. offers explosion-proof engineering construction services for hazardous explosive areas.
1. Explosion-proof site inspection and consultation
2. Explosion-proof engineering construction and renovation on-site
3. Explosion-proof construction acceptance
4. Explosion-proof electrical installation, maintenance, and renovation
5. Explosion relief walls, doors, and windows installation
6. Dust Removal Equipment Installation and Retrofitting Construction

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 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-conductive ground areas: Equipment with alternating current rated voltage of less than 1000V and direct current rated voltage of less than 1500V, which has normal, non-electrified metal enclosures.
2) In dry environments, equipment with alternating voltage ratings of 127V or less and direct voltage ratings of 110V or less typically do not carry live electrical charges on their metal enclosures.
3) Equipment installed on a grounded metal structure.
(2) In explosive hazardous environments, the exposed, conductive parts of 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 a dedicated grounding wire. If this 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 use a metal piping system with a reliable electrical connection as a grounding wire, but not a pipeline for conveying materials.
(3) In different directions on the slope of the explosion hazard area, the grounding main should be connected to the grounding body at no fewer than two points.

Basic Knowledge and Requirements for Cable Use in Explosion-Proof Construction Sites (Shared by Shenzhen Zhongnuo Testing Technology Co., Ltd.)
Installation methods for electrical wiring in explosive gas environments can be divided into cable wiring and conduit wiring methods.
Note: The installation of intrinsic safety circuits may not be in accordance with the provisions of this article.
7.1 General Provisions
7.2 Electrical wiring should be installed in areas of lower explosion hazard or at a greater distance from the source of release, avoiding places susceptible to mechanical damage, vibration, corrosion, dust accumulation, and hazardous temperatures. If avoidance is not possible, preventive measures should be taken.
7.3 The selected low-voltage cables or insulated conductors must have a rated voltage higher than the working voltage of the line and not less than 500V. Insulated conductors must be installed within conduits.
7.4 It is strictly prohibited to cross explosive gas environments with overhead lines of 10kV and below; the horizontal distance between the overhead line and the explosive gas environment should not be less than 1.1 times the height of the pole.
7.5 Cables and their accessories shall be installed in such a position that, in view of the actual conditions, they are protected against external mechanical damage, corrosion, or chemical influences (such as the effects of solvents), as well as the effects of high temperatures (also see 6.1.2.4.4 for this safety circuit). If such conditions cannot be avoided, protective measures shall be taken during installation, such as using conduits or selecting appropriate cable types (armored cables, shielded wires, seamless aluminum sheathed cables, mineral insulated metal sheathed cables, or semi-rigid sheathed cables, etc., to minimize damage).
7.6 Solid-core wire without sheath should not be used for conductive wiring unless installed within a distribution board, housing, or conduit system.

According to the basic requirements of GB 15577 "Safety Code 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 Inspection and Technology Co., Ltd.).
Anti-knock
1. Definition: A suppression technology that allows the enclosed package to withstand the pressure of a large explosion when combustible dust and gaseous oxidizers or air are present inside, ensuring the package is not destroyed.
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 handling powders that can cause explosions, if there is no explosion suppression device and no pressure relief measures, all process equipment should be equipped with explosion-proof design and capable of withstanding the overpressure from 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 shall comply with the relevant requirements of GB/T 24626.
2. Explosion Relief
1. Definition: A fire suppression technology that allows the high temperature, high-pressure combustion products, and unburned materials generated by an explosion within the containment vessel to be vented through pre-set weak points to a safe direction before the explosion pressure reaches the containment vessel's limit strength, thereby preventing the vessel from being destroyed.
2. Purpose: To reduce explosion losses by installing explosion relief devices.
3. Methods: Two types of explosion relief - Flaming and Non-flaming.
4. Basic Requirements:
If the strength of the process equipment is insufficient to withstand the overpressure generated by the internal dust explosion under its actual operating conditions, a venting port should be installed. 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 be no less than the strength of the protected equipment container.
(3) Equipment within the room that cannot vent to the outside through a pressure relief conduit should be equipped with flameless venting caps.
(4) Process equipment with inline piping should be designed to withstand at least 0.1 MPa of internal overpressure.
3. Explosion Suppression
1. Definition: In the initial stage of an explosion, extinguish the flame and suppress (prevent) the development of dust explosion through physical and chemical actions.
2. Purpose: To detect and extinguish fires, and suppress explosions in advance through the installation of 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 meet 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 through physical and chemical actions after its occurrence.
2. Purpose: To prevent the spread of flames through pipes or other passages
3. Basic Requirements:
(3) Equipment and facilities with dust explosion hazards, interconnected through pipelines, should ideally 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: Inertization
For processes such as crushing, grinding, drying of powders, and pneumatic conveying through pipelines within sealed containers, inert gases such as nitrogen, carbon dioxide, halogenated hydrocarbons, argon, helium, and steam are introduced, as well as inert dusts like fire extinguishing powder, chemical dry powder, and mineral rock powder. This is done to dilute combustible components and reduce the oxygen content in the environment.
Explosion-proof electrical modifications and on-site explosion-proof construction consulting services for hazardous areas — Shenzhen Zhongnuo Testing Technology Co., Ltd.