What is a helmet?
A hat that protects human head from falling objects and other specific factors is called a helmet. It consists of a cap shell, a cap liner, a chin strap and other accessories. The cap shell consists of shell, visor, brim and top rib. The helmet lining is the general name of the internal parts of the helmet shell, which consists of the helmet hoop, the sweat absorption belt, the lining belt and the buffer device. The chin strap is a strap that is tied to the chin and plays a fixed role. It consists of a strap and a locking clip.
The impact force instantly decomposes to the whole area of the skull, and then most of the impact force is absorbed by the elastic deformation, plastic deformation and allowable structural damage of various parts of the helmet, such as helmet shell and helmet lining, buffer structure (socket, tether, suture, buffer pad, etc.). ), so that the final impact on the operator's head is reduced to below 4900N, thus protecting the operator's head from injury or reducing the injury.
Safety helmet classification
Safety helmet is one of the important personal protective equipment, with large output and wide use. There are many kinds of safety helmets, and the structural forms of safety helmets are also diverse. According to the use of safety helmet, it can be divided into general operation and special operation. General working helmet has general impact protection performance, and is used in workplaces with impact injuries such as construction and shipbuilding operations. In addition to the general impact protection performance, special operation safety helmet also has special protection performance, which is used in workplaces with special protection requirements, such as electrostatic protection, lateral rigid protection, flame retardant protection, low temperature protection and so on. According to the material of helmet shell, it can be divided into plastic helmet, FRP helmet, plastic helmet, bamboo helmet and aluminum alloy helmet. The first four kinds of helmets are widely used because of their large production capacity, while aluminum alloy helmets are rarely produced and used. According to the size of helmet brim, it can be divided into no brim, small brim, middle brim and big brim. No matter what the material and structure of the helmet are different, the technical requirements are the same according to the use category of the helmet.
Safety helmet material
1. Hat shell material
Helmet shell materials mainly include synthetic resin, metal, colloid and plastic helmet. The material of helmet shell plays an important role in the overall impact resistance of helmet. Therefore, the appropriate materials should be selected according to the different structural forms of helmet shell.
At present, the synthetic resin materials for safety helmets widely used at home and abroad include unsaturated resin, polycarbonate, ABS, high molecular polyethylene, modified polypropylene and so on. The safety helmet made of these materials has good impact resistance, light weight and good appearance quality, and there are many structural forms to choose from.
The impact resistance of helmets made of metal materials (such as aluminum alloy) is not as good as that of plastic and FRP helmets. This kind of helmet can't be used in the workplace where there is danger of electric shock.
Rubber helmet has good impact resistance, rigidity, high temperature resistance, corrosion resistance and antistatic property, and has long been the first choice for underground miners.
The safety helmet made of bamboo strips is a unique material in China, which was widely used in southern China in the early years. The safety helmet made of bamboo strips has good toughness, good impact resistance, the best air permeability and poor puncture resistance. Generally, a steel plate is added to the top of the helmet shell to enhance its puncture resistance. Bamboo safety helmet is not flame-resistant and cannot be used in workplaces with fire sources. Moreover, the bamboo safety helmet is hand-woven, and the quality is not guaranteed. In recent years, the number of bamboo helmets in China has become less and less.
2. Hat lining material
The materials of helmet lining mainly include high and low pressure polyethylene, synthetic fiber, cotton woven belt and so on. Hat lining materials should have good strength and impact resistance, and have no harmful and allergic effects on the skin. When selecting hat lining materials, we should consider the coordination with the performance of hat shell materials.
technical requirement
Size requirements. The size requirements of safety helmet mainly include: the internal size of helmet shell, visor, brim, vertical spacing, horizontal spacing, wearing height, protruding parts and air holes. Among them, vertical spacing and wearing height are two important size requirements of safety helmet. Vertical spacing means that when the helmet is worn, there is no axial distance between the vertex and the inner surface of the helmet shell (excluding the space between the top bones and muscles). The size requirement is 25mm ~ 50mm. Wearing height refers to the axial distance from the bottom edge of the helmet hoop to the highest point of the head when the helmet is worn. The size requirement is 80 mm ~90 mm, too small vertical spacing directly affects the impact absorption performance of the helmet, and too small wearing height directly affects the wearing stability of the helmet. Failure to meet either of these two requirements will directly affect the overall safety of the helmet.
Weight requirements. Under the premise of ensuring safety performance, the lighter the helmet, the better, which can reduce the neck fatigue caused by workers wearing it for a long time. The weight of small edge, middle edge and hemmed helmet shall not exceed 430g, the weight of large edge helmet shall not exceed 460g, and the weight of cold-proof helmet shall not exceed 690g (the above weight requirements do not include additional parts). Safety performance requirements. Safety performance refers to the protective performance of safety helmet, including basic performance requirements and special performance requirements, and is an important index to judge whether the safety helmet product is qualified or not. Safety helmet standard GB28 1 1-2007 clearly stipulates the requirements that safety helmet products should meet. These performance requirements are the indicators that products must meet. Whether the safety helmet can be manufactured, sold and used depends on the producers, users and marketers.
mark of conformity
The state implements industrial production license management and safety identification management for safety helmets. GB28 1 1-2007 safety helmet is a mandatory standard. The production enterprise of safety helmet products must pass the examination and approval of the competent department, have the necessary environmental conditions and facilities, product inspection equipment, quality management personnel, inspectors, technicians and production personnel, and have the ability to organize production, quality management and control, and factory inspection. Every batch of products produced by an enterprise must pass sampling inspection before leaving the factory. The factory products of the enterprise shall be labeled with the following information: ① Name and category; ② Name and address of the enterprise; ③ year of manufacture; (4) factory certificate; ⑤ Marking of production license marks and numbers; ⑥ Product implementation standards; ⑦ Contents required to be marked by laws and regulations.
facility request
According to the Standard of Labor Protection Articles (for Trial Implementation) issued by the State Economic and Trade Commission on March 6, 2000, there are 25 typical jobs involving helmets, including foundry workers, electricians, foremen, cold workers, road builders, oil drillers and coal miners. Every typical job has many similar jobs. For example, there are 32 similar posts for electricians and 145 similar posts for headgear workers. Enterprises should be equipped with safety helmets according to the standard of protective equipment in the standard, and operators can also put forward the requirements in accordance with the regulations.
Safety helmet selection
When choosing a helmet, users should pay attention to choosing a helmet that meets the relevant national management regulations, has complete marks and is qualified after inspection, and should check its recent inspection report. And different varieties should be selected according to different protection purposes. For example, users in live workplaces should choose safety helmets with electrical insulation and pass the inspection. When working in low temperature environment, you should choose a safety helmet with low temperature protection performance and passed the inspection. Otherwise, the required protection requirements cannot be met.
Use and storage
Improper wearing will cause the helmet to fail to play a protective role when it is hit. Safety helmet According to the statistics of relevant departments, 15% of falling objects injuries are caused by improper use of safety helmets. Therefore, the helmet cannot think that wearing a helmet can protect the head from injury. In the process of use, we should pay attention to the following issues:
1. Before using the safety helmet, check whether the appearance of the safety helmet is cracked, bruised, uneven and worn, whether the cap lining is complete and whether the cap lining structure is in a normal state. If there are obvious defects on the safety helmet that affect its performance, it should be scrapped in time to avoid affecting the protection effect.
2. Users can't remove or add accessories to the helmet at will, so as not to affect its original protective performance.
3. Users can't adjust the size of the helmet liner at will, which will directly affect the protective performance of the helmet. Once a falling object impacts, the helmet will fall off due to wearing instability or hit the top after impact, which will directly hurt the wearer.
4. When using the helmet, the wearer must wear the helmet straight and firmly, and can't shake it. Fasten the chin strap and adjust the iron ring to prevent the helmet from falling off.
5. Don't punch holes in the helmet without permission, don't bump the helmet at will, and don't sit the helmet as a bench to avoid affecting its strength.
6. Hard hats that have been impacted or tested should be scrapped and cannot be used again.
7. The safety helmet cannot be stored in an environment polluted by acid, alkali or chemical reagents, nor can it be placed in a place with high temperature, sunlight or high humidity to avoid its aging and deterioration.
8. Pay attention to the use of safety helmet within the validity period. The safety helmet woven with plant branches is valid for 2 years, the plastic safety helmet is valid for 2 and a half years, the glass fiber reinforced plastic (including vinylon steel) and gel safety helmet is valid for 3 and a half years, and the safety helmet beyond the validity period should be scrapped.
Defendant: Shanghai Mingxi Safety Equipment Co., Ltd.-a professional helmet manufacturer!