Explosion Protection Experts in Hazardous Areas
How should a chemical explosion-proof cabinet be earthed? Explosion-proof cabinet of the five major role
Time: 2023-09-26 16:56:44   Clicks: 129

One, first of all, what is the explosion-proof cabinet?

Explosion-proof cabinet scientific name is fire safety cabinet, also called it chemical safety cabinet, fire cabinet, chemical explosion-proof cabinet, we have different names to it, explosion-proof cabinet has 4 kinds of colors, respectively: yellow, red, blue, white, the chemical stored by each color is not the same.

 Two, the explosion-proof cabinet must be equipped with an anti-static end

Hazardous chemical fire cabinets will be strictly in accordance with OSHA specifications with anti-static grounding wire, this is necessary.

 There are three reasons for this:

1. In the process of production, processing, storage and transportation, equipment, pipelines, operating tools and human body, which may produce and accumulate static electricity, static grounding measures shall be taken.(As shown above: there is a small screw on the right side of the explosion-proof cabinet is used for grounding), the general iron cabinet can not be equivalent to the hazardous chemical fire prevention cabinet.

2. The legal and regulatory requirements. In GB 15603-2022 General Rules for Storage of Hazardous Chemicals Warehouse, the building exhaust system for storing dangerous chemicals shall be equipped with a grounding device to remove static electricity.

3. Referring to the Regulations on the Safety Management of Hazardous Chemicals, Regulations on the Safe Use of Chemicals in Workplaces and other regulatory documents, the requirements for static electricity.

 What is the common grounding wire of the dangerous chemical fire prevention cabinet? Let's look at the picture, is generally as the above, of course, some special occasions need to support a larger anti-static clip. Regular use of this is also enough. What are the benefits of hazardous chemical fire prevention cabinet grounding?1: do not produce static electricity will not lead to the cabinet caused by static electricity 2: can be well through the inspection 3: protect the dangerous goods stored in the cabinet. Therefore, the hazardous chemical fire prevention cabinet must be properly grounded to ensure safe storage and use.

 Three, what is the grounding wire like?

What is the common grounding wire of the dangerous chemical fire prevention cabinet? Generally as shown in the picture, of course, some special occasions need to support a larger anti-static clip. Regular use of this is also enough.


Four, anti-static grounding type

 Grounding is the simplest and most commonly used way to eliminate electrostatic disasters, which includes the following three types.

(1) Direct grounding, that is, the metal conductor and the earth for conductive connection, so that the potential of the metal conductor is close to the earth potential of a grounding type.

(2) Indirect grounding, that is, in order to electrostatic ground the electrostatic conductor and static voltage conductor outside the metal conductor, all or part of its surface is closely connected with the grounded metal conductor, and the metal is used as a type of grounding electrode.

(3) Interconnect grounding, that is, a type of grounding fixed between metal objects by mechanical and chemical methods, so that two or more insulating metal conductors are conductive, so as to establish a low impedance path to provide current flow, and then grounding.


Five, anti-static grounding precautions

 Ground is used to eliminate static electricity on the conductor, but not on the insulator. If the insulator with static electricity is directly grounded by the conductor, that is equivalent to leading the earth potential to the insulator, but will increase the risk of spark discharge, so the method of anti-static grounding is only applicable to the conductor.

 Anti-static grounding device can be shared with the working, protection and repeated grounding device of electrical equipment. The grounding connection line shall ensure sufficient mechanical strength and chemical stability. The connection shall be reliable without any interruption. The antistatic grounding resistance value usually should not exceed 1 MΩ.

 Storage of flammable gas, liquefied gas, liquid hydrocarbon, or other storage tanks with fire hazard shall be reliably grounded; storage with volume greater than 50m3 shall be grounded along its diameter direction and not less than 2 places. In use, avoid accidental collision and breaking of anti-static grounding wire and grounding device; the flange of the pipe shall have good electrical conductivity.

 Conductive ground is also essentially a grounding measure. It can not only guide the static electricity on the equipment, but also help to guide the static electricity on the human body. Conductive ground often refers to concrete, conductive rubber ground, conductive synthetic resin, conductive board, conductive terrazzo, conductive ceramic tile and other ground. When the conductive ground or conductive coating is used to spray the ground, the resistance value between the ground and the earth should not exceed 1 MΩ, and the contact area between the ground and the grounding conductor should not be less than 10cm2.

 In some dangerous places, in order to make the rotating shaft can be reliably grounded, conductive lubricating oil or grounding the sliding ring and carbon brush grounding can be used.

 In order to eliminate human static electricity, you can wear conductive working shoes (such as leather shoes or conductive rubber sole shoes), which is also essentially a grounding measure. The resistance of the conductive working shoe shall be 10 MΩ.

Incidentally, in order to prevent the body from static electricity, wearing silk or synthetic fiber clothes should be avoided in the workshop, especially in places of explosion or fire. In addition to the electrical equipment must take explosion-proof measures and strictly implement the relevant rules and regulations, the staff should pay attention not to wear with nylon, nylon, polyester or made of clothes, gloves, socks, or scarves, tools should try not to use plastic or nylon products, to eliminate static electricity may cause fire or explosion risk. Prevent accidents from.

Five major functions of the explosion-proof cabinet


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1. Using explosion-proof cabinet to store hazardous chemicals can effectively prevent chemical spillover and prevent fire accidents;

2. The safe use of explosion-proof cabinet can not only protect the safety and health of the working environment, but also protect the life and property safety of the enterprise employees;

3. Reduce costs and improve work efficiency. Because the explosion-proof cabinet volume is small, it can be placed in the workplace to store inflammable and explosive products, do not frequently travel to and from the dangerous goods storage room, save time and effort;

4.  The effective management of various dangerous goods, different colors of the safety cabinet function is not the same, the storage chemical supplies are also different, classified storage, at a glance, easy to manage;

5. In the process of storing chemicals, colored labels are used to identify, organize and separate various flammable or dangerous liquids, so as to facilitate firefighters to identify dangers in case of fire.

 

The following safety matters also need to pay attention to when using the explosion-proof cabinet

 Although the explosion-proof cabinet has the function of fire and explosion proof, but after all, explosion-proof cabinet storage is also very special. If you do not pay attention to it, it will also cause safety accidents. Therefore, the following matters must be noted when using the explosion-proof cabinet:

☑ The explosion-proof safety cabinet is equipped with a double exhaust port with a built-in flame filter (with a plug), usually located on both sides of the cabinet, one side is high and one side is low. According to the relevant safety specifications, if not exhaust, the exhaust port shall be sealed with plugs; if the safety cabinet needs exhaust for any reason, it shall be set according to the relevant safety standards and shall not affect the performance of the explosion-proof safety cabinet.

☑ Steel safety cabinet with a built-in grounding pad, generally located on the bottom right side. For the safe storage of flammable materials, it is necessary to be grounded as far as possible for safety reasons. If the distribution and collection process is performed in the safety cabinet, such as pumping from the barrel or pouring waste liquid through the funnel, the safety cabinet shall be grounded and the container direct correct bonding technology is essential.

☑ The ground of the explosion-proof safety cabinet shall be flat.

☑ If multiple explosion-proof safety cabinets are placed together, the spacing between each cabinet should not be less than 15 cm.

☑ The explosion-proof safety cabinet should be placed away from the fire source or other heat dissipation instruments and equipment, but also away from the splashing chemical liquid or slag.

☑ There is an electrostatic guide terminal column at the lower corner of the right outer wall of the cabinet. After the cabinet is properly placed, the electrostatic grounding wire should be connected to guide the static electricity accumulated in the cabinet in time.

☑ Items placed on the cabinet board should not exceed the load-bearing limit of the board. If there are multiple layers, when placing items, larger or heavier items should be placed on the underlying layer, and smaller or lighter items should be placed on the upper layer layer.

☑ If the explosion-proof safety cabinet is placed in a closed narrow space, or the place where the cabinet is placed has strict restrictions on the volatilization of flammable liquid, then the ventilation system should be connected to the vent of the cabinet to eliminate the flammable liquid accumulated in the cabinet due to volatilization.

☑ At night or under the condition of insufficient dark light, if it is necessary to place items or conduct other operations in the cabinet, you should turn on the surrounding lights, or carry an explosion-proof flashlight for operation.

☑ It is strictly prohibited to light candles, alcohol lamps or use lighters and any operation that may cause combustion and explosion.

☑ Smoking, throwing fireworks or discarding other burning objects in the storage place.

☑ After the door is opened, close and lock. Never open the door for a long time to avoid fire sources entering the cabinet.

☑ Usually pay attention to protect any door lock installed on the cabinet, to avoid the door lock impact or other damage.

☑ Usually pay attention to protect the cabinet, prevent collision, scraping or corrosive chemical liquid splashing on the cabinet, so as not to touch the cabinet or destroy the coating on the cabinet.

☑ It is strictly prohibited to put strong corrosive chemicals in the explosion-proof safety cabinet. Strong corrosive chemicals shall not be placed in the same cabinet as flammable and combustible chemicals, and special cabinets of highly corrosive chemicals shall be purchased for classified storage.

☑ Any locking placement installed on the cabinet is required to be responsible for management, and prohibit non-management personnel to open at random.

☑ It is recommended that the manager of the key have an additional set of keys in advance for the key to be damaged or accidentally lost.

Explosion-proof cabinet is not absolutely safe, with the right is "safety cabinet", with the wrong is "life cabinet", the enterprise, university laboratory must attach great importance to, strengthen the investigation of safety hidden dangers, manage the explosion-proof cabinet!