Welding and cutting operations to include mechanical damage, electromagnetic radiation, ionizing radiation, noise and vibration, dust and harmful gas, such as all kinds of harmful factors, engineering control measures are often preferred way to reduce risk factors, including using new type of welding equipment and materials, local dust exhausting device, the workshop overall ventilation, etc. But in some cases due to the cost, environment and other factors, the implementation of engineering control measures has become very difficult or not feasible, and the purpose of engineering control measures is more mainly to improve the overall environment, not necessarily can completely eliminate the hazard factors welders face. Personal protective equipment as the last line of protection for welding mask will help reduce the risk of occupational injuries to welding operators and associated personnel.
Welding protection welding mask is a kind of protection against harmful light radiation, molten drop, molten metal splash and thermal radiation.Protective equipment for facial injury includes welding cover and welding goggles, among which welding goggles provide eye protection. welding The welding mask is not only the protective equipment for welding occupational hazards, but also the necessary auxiliary tools for welding operations In recent years, eye injury still accounts for the largest proportion of welder occupational injury.
There are various forms of welding masks. According to different structural forms, welding masks can be divided into three types: hand-held welding mask(see Figure 1) head-mounted welding mask(see Figure 2) and combined welding mask(see Figure 3). According to its working principle, it can be divided into traditional welding mask (also known as black glass welding mask) and automatic light changing welding mask. According to whether the air supply device is connected, it can be divided into electric air supply welding mask, long tube air supply welding mask and ordinary welding mask. The biggest characteristic of the hand-held welding mask is that it is cheap, but the disadvantages are also very obvious, that is, it can not carry out accurate welding operation with both hands, and the welder’s labor intensity is high and the actual protection area is limited. The head-mounted welding mask has obvious advantages for high welding quality and efficiency requirements or special welding positions. Combined or welded helmet masks provide head protection as well as eye and face protection. Air supply welding mask provides respiratory protection while protecting the operator’s eyes and face Combined welding mask.
Hand-held welding mask is a common welding mask, which is widely used because of its low price. Hand-held welding mask consists of face shield and filter. When welding, one hand welding mask is used for operation. The material of the hand-held welding mask cannot be irritating to the skin and is not flammable. The commonly used welding mask materials include nylon and red steel paper.
According to GB/ T3609.1-2008 Occupational Facial Protection Welding Protection part 1: Welding Eye Protection, observation window of welding mask ≥90mm×40mm, length ≥310mm, depth ≥120mm, width ≥210mm of hand-held welding mask, and the quality of the filter, safety helmet and other accessories should be 500g or less.
GB/T3609.1 specifies the transmittance, optical performance and optical performance of welding mask filter. Welding mask shall not leak light. The welding filter is divided into 19 shading numbers. The color of the welding filter is mixed color, and the wavelength of the maximum transmission ratio should be between 550-620mm. At the same time, the impact resistance of welding cover (national standard only for falling ball test, not high-speed particle impact test), flame retardant, heat resistance, penetration, corrosion resistance and electrical insulation performance and other non-optical properties are required. The above optical and non-optical performance requirements apply to hand-held and head-mounted welding masks. Welding masks used for arc welding protection shall be resistant to metal droplets and hot solids, although the splashes of hot particles may not be noticeable in some welding methods.
GB/T3609.1 does not require the performance of metal droplets and hot solid and the performance of anti-drop testing requirements. The European standard requires that two welding surface samples are prefabricated for 120min in (80±2)C high temperature environment and (-5+2)C low temperature environment respectively. Within 10s after being taken out of the prefabricated environment, the welding mask is dropped from (1.50±0.01)m to the testing platform. After falling, the samples are returned to the original prefabricated environment and stand for at least 30min. Repeat the drop test. The experiment was repeated three times. During the whole test process, the welding mask shall not appear obvious deformation, crack or rupture, and permanent damage affecting the protection performance; The welding filters and protectors are also free from any permanent damage that may affect the protection.
For metal droplet and hot solid resistance, European standards for claim with metal droplet and hot solid resistance welding protective equipment, in addition to the protective area should comply with the relevant requirements, still must through about 6 mm in diameter, temperature for (900 + 20) ℃ steel heat penetration test, including Windows part in 7 s internal may not appear penetrate phenomenon, other part within 5 s No penetration shall occur.
In addition, the requirements of light transmittance, electrical insulation, ignition resistance and thermal penetration of the mask.