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!
Protection of explosive loop circuits shall comply with the following regulations (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
In the single-phase network within Zone 1, both phase and neutral lines should be equipped with short-circuit protection, and appropriate switches should be used to simultaneously disconnect both the phase and neutral lines.
(2) For 3kV-10kV cable lines, it is advisable to install zero-sequence current protection, with the protective devices in Zones 1 and 21 designed to trip the circuit breaker.

Shenzhen Zhongnuo Testing Technology Co., Ltd. offers explosion-proof engineering construction services in the field of:
Including industries such as petrochemicals, metal smelting, fine chemicals, petrochemical ground facilities (gas stations, gas filling stations, petrochemical warehousing and transportation, etc.), new energy, special equipment, nuclear power, tunnels, grain processing, wood processing, metal component manufacturing, environmental protection engineering, and more, there are hazardous areas with explosive gas environments and environments with explosive or flammable dust. Ensuring the explosion-proof safety of these dangerous explosive areas safeguards our and the national economy's development.

Selection of cables and wires for explosive environments should comply with the following regulations: (Shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
(1) In explosive environments, the rated voltage of insulated conductors and cables used for low-voltage power and lighting lines should be higher than or equal to the working voltage, and U0/U should not be less than the working voltage. The rated voltage of the neutral line should be equal to the phase voltage and should be laid in the same sheath or protective tube.
(2) In explosive hazard zones, except within distribution panels, junction boxes, or metallic conduit wiring systems, unshielded wires should not be used as supply and distribution lines.
(3) Copper-core cables should be used in Zone 1. In Zone 2, copper-core cables are recommended except for inherently safe circuits. When aluminum-core cables are used, their cross-sectional area must not be less than 16 square millimeters, and copper-aluminum transition joints should be used for connections to electrical equipment. Circuits installed in explosive dust environments in Zones 20 and 21, as well as in areas with severe vibration in Zone 22, must use copper-core insulated conductors or cables.
(4) The technical requirements for wiring of cables in explosive environments, excluding the circuitry of the present pressure safety system, shall comply with the specifications in Table 5.4.1-1.
(5) Technical requirements for piping wiring in explosive environments with voltages below 1000V, except for circuits of inherently safe systems, should comply with the specifications in Table 5.1.1-2.
(6) In explosive environments, the selection of insulated conductors and cable cross-sections shall comply with the provisions of Tables 5.4.1-1 and 5.4.1-2, as well as the following requirements:
1) The conductor's current-carrying capacity should not be less than 1.2 times the rated current of the fuse element and 1.2 times the setting current of the long-time delay overcurrent release of the circuit breaker, except for the cases specified in item 2 of this clause.
2) The long-term permissible current for the branch line of squirrel-cage induction motors with a voltage of less than 1000V should not be less than 1.2 times the rated current of the motor.
(7) When installing overhead or bridge cable trays, it is advisable to use flame-retardant cables. Plastic sheathed cables without armor can be used when the installation method employs bridge trays that prevent mechanical damage. Cables without armor can also be installed in cable trenches in Zones 2 and 22 when there is no risk of damage from rodents or insects.

According to the basic requirements of GB 15577 "Safety Regulations for Dust Explosion Prevention," in the防爆 construction and modification of 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 containment technique that allows a sealed compartment to withstand the explosive pressure during an explosion involving combustible dust and gaseous oxidizers or air, preventing the compartment from being destroyed.
2. Objective: By enhancing container wall thickness and improving materials, external damage can be 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 designed with explosion-proof features and capable of withstanding overpressure from internal explosions without bursting.
(2) The connecting 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.
2. Bursting Discs
1. Definition: A containment explosion suppression technique that allows the high temperature, high-pressure combustion products, and unburned materials generated by an explosion within the containment to be released through pre-set weak points on the containment structure to a safe direction before the explosion pressure reaches the containment's limiting strength, thereby preventing the containment from being destroyed.
2. Purpose: To reduce explosion losses by installing explosion relief devices.
3. Methods: Two explosion relief methods available, with flame and without flame.
4. Basic Requirements:
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. The relief ports should be directed towards a safe direction, and the size of the relief ports 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 ducts. The pressure relief ducts 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 protected equipment container.
(3) Equipment within the room that cannot vent explosive gases outdoors through 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.
Section 3: Explosion Suppression
1. Definition: In the initial stage of an explosion, extinguish the flames and suppress (prevent) the progression of dust explosion through physical and chemical means.
2. Objective: To detect and extinguish fires, and suppress explosions prematurely through the installation of an explosion suppression device.
3. Basic Requirements:
Process equipment with a risk of dust explosion should be protected by using explosion suppression devices.
(2) If a monitoring-type 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 used to prevent the spread of an explosion through physical and chemical actions after the explosion occurs.
2. Purpose: Prevent flame from spreading through pipelines or other passageways
3. Basic Requirements:
(3) Equipment and facilities with a dust explosion hazard that are interconnected via pipelines should ideally be equipped with explosion suppression devices on the pipelines.
(2) Equipment and facilities with a dust explosion hazard that are interconnected by pipelines should be equipped with explosion-proof devices on the pipelines. The shutdown direction should align with the direction of the explosion's 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, or 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.
explosion-proof electrical modifications and on-site explosion-proof construction consulting services for hazardous areas — Shenzhen Zhongnuo Inspection Technology Co., Ltd.