Shenzhen Zhongnuo Inspection & Technology Co., Ltd. is based in South China, offering explosion-proof construction, safety inspections, renovations, project acceptance, and installation services. We are well-versed in explosion-proof construction standards, boast experienced construction teams, and have served major enterprises like PetroChina, LG, Hanlan Environment, BOE, 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 Area 1, both phase lines and neutral lines should be equipped with short-circuit protection, and appropriate switches should be used to simultaneously disconnect both phase lines and neutral lines.
(2) For 3kV-10kV cable lines, it is advisable to install zero-sequence current protection, and the protective devices in Zones 1 and 21 should be set to trip.

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 site construction and renovation
3. Explosion-proof Construction Acceptance
4. Explosion-proof electrical installation, maintenance, and renovation
5. Explosion relief, blast-resistant walls, doors, and windows installation
6. Dust Removal Equipment Installation and Retrofitting Construction

Basic Requirements for Explosion-Proof Electrical Installations in Hazardous Areas (Shared by Shenzhen Zhongnuo Testing Technology Co., Ltd.)
1. Oil-immersed equipment should be used under conditions of no vibration, no tilt, and fixed installation.
2. When using non-explosion-proof equipment for mechanical transmission as partition walls, the following regulations should be adhered to:
The room housing electrical equipment should be separated from the explosive hazardous area by a solid wall made of non-combustible material.
(2) The drive shaft transmission through the partition wall should use a stuffing box seal or an equivalent sealing measure.
(3) The exit of the electrical equipment room should lead to an environment free of explosive hazard areas.
(4) When the room housing the equipment must be connected to an explosive atmosphere, a positive pressure relative to the explosive atmosphere should be maintained.
3. Electrical circuits and equipment in explosive environments, excluding inherently safe circuits, should be equipped with overload, short-circuit, and grounding protection. Overload protection is not required for electrical equipment that cannot experience overloads. Motors in explosive environments, in addition to the necessary protection as required by current standards, should also be equipped with phase failure protection. If the automatic shutdown of electrical equipment could pose a greater risk than the ignition hazard, an alarm device should be used in place of the automatic shutdown device.
4. In emergency situations, appropriate measures should be taken at a suitable location outside the hazardous area to disconnect the power supply to the equipment in the hazardous area. Continuous operating equipment should not be included in the emergency shutdown circuit and should be installed on a separate circuit to prevent the occurrence of additional hazards.
5. The design of transformer stations, sub-stations, and control rooms shall comply with the following regulations:
Transformer substations, distribution stations (including distribution rooms, hereinafter), and control rooms should be located outside of explosive gas environments. When it is a pressurized room, they can be arranged within Zones 1 and 2.
(2) For explosive gas environments heavier than air, the equipment floor of electrical and instrumentation in power substations, distribution stations, and control rooms located in the additional 2nd zone of the explosion hazard area should be elevated 0.6 meters above the external ground level.

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-proof measures on-site is particularly important. The installation and use of explosion-proof wiring, electrical equipment, dust removal systems, architectural layout, and explosion-proof venting must all comply with the relevant dust explosion-proof standards. Based on a wealth of explosion-proof electrical installation and retrofitting cases, Shenzhen Zhongnuo Testing Technology Co., Ltd. has summarized the following points:
1. Structure and layout of buildings
(1) Equipment or structures with processes posing a dust explosion hazard or containing combustible dust should be separated from other buildings, 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 utilize lightweight construction.
(3) The structural requirements for multi-story buildings are as follows:
A. Multi-story 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 explosion relief ports, they must be calculated and ensured to effectively vent during an explosion.
(4) The 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
(1) If there are process equipment with a risk of dust explosion in the factory, they should be located on higher floors and close to the outer walls of the building.
(2) Equipment with explosive hazards should be located in an outdoor area outside the building.
(3) Equipment or devices in direct contact with dust (such as light sources, heating sources, etc.) should have surface temperatures lower than the respective low ignition temperature of the dust.
(4) In areas where combustible dust is present, the transmission mechanisms of the equipment and installations shall comply with the following regulations:
The bearings of the process equipment should be dust-proof and sealed. If overheating is possible, a detector capable of continuously monitoring the bearing temperature should be installed.
B. Belt drives are not recommended; if used, speed difference sensors and automatic anti-slip protection devices should be installed. In the event of sliding friction, the protection device must ensure automatic shutdown.
(5) At the feed point of the process flow, magnets, pneumatic separators, or screens capable of removing impurities mixed in the material should be installed to prevent the collision of impurities with the equipment.
(6) Effective measures should be taken to prevent sparks from occurring when aluminum, zirconium, and other metal powders, or powders containing these metals, come into contact with stainless steel.
(7) Upon explosion, protective shutdown should be implemented. Depending on the size of the workshop, several power supply control cabinets capable of interlocking with each other should be installed. In emergency situations, the power supply to all motors should be able to be cut off promptly.
(8) All joints, inspection doors, baffles, and explosion vent covers of the process equipment should be sealed tightly
(9) The equipment housing should be made of non-flammable materials
(10) The moving parts of the equipment should operate smoothly without any scraping, bumping, jamming, or rubbing.
(11) If 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, and the size of the relief openings should comply with the relevant provisions of GB/T15605.
(12) The venting port should be located near potential ignition sources, and it should be as high as possible, ideally at the top or upper part of the containment structure. It must not vent towards flammable and explosive hazardous areas to prevent igniting others, and it must not vent towards public areas to avoid causing injury from venting explosions.
3. Lightning and Static Electricity Protection
Hazardous dust explosion areas should adopt lightning protection measures in accordance with the relevant provisions of GB50057. When static electricity hazards are present, the following regulations should be observed:
All metal equipment, device casings, metal pipes, brackets, components, parts, etc., are generally grounded statically via 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 electrostatic powder, such as conveyance pipes (belts) for the powder, should be made of metal or antistatic materials.
(3) All metal pipe joints should be bonded across.
(4) Operators should take anti-static precautions.
(5) Do not use metal conductors or meshes that are directly grounded to contact high-speed flowing powder to dissipate static electricity.
Explosion-proof electrical renovations and on-site explosion-proof construction consulting services for hazardous areas - Shenzhen ZhongNuo Testing Technology Co., Ltd.