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Why is welding fume dangerous?

There are many substances harmful to health in the smoke generated during the welding process. Welding fume contains heavy metals. In welding and cutting processes, various gases are produced as a result of the combustion or evaporation of welding consumables, cutting fluid on the main material to be welded, residues such as oil, grease and coatings such as paint, galvanising with the effect of arc temperature. In addition to gases such as carbon monoxide, carbon dioxide and nitrous oxide as a result of combustion of combustible gases such as acetylene, propane, butane, methane used in gas welding and brazing processes with oxygen gas, as well as particles and vapours of metals such as zinc, copper, cadmium, lead and fluoride and chloride based gases depending on the filler material, decapsulants and the base material on which the process is performed. In welded manufacturing workshops, gases, dust and fumes that are formed due to the production process and spread to the working environment enter the body by inhalation. Some of these air pollutants can cause chronic (long-term) diseases as well as acute (sudden-suddenly) disorders depending on the level of exposure. For example, metal fume fever, which is frequently seen in welders, is usually a temporary discomfort, but it also helps the development of chronic diseases. If there are more pollutants than the permitted density in the working environment in welded manufacturing workshops and if this air is inhaled, depending on the duration and intensity of exposure; respiratory difficulties, blood diseases, cancer, chronic bronchitis, headache, pulmonary oedema, metal fume fever, irritation of the mouth and nasal mucosa may occur. In addition, damage to the central nervous system, kidneys, liver, blood-forming system and bone structure may occur and related diseases may occur. Occupational diseases called pneumoconiosis occur when metal-containing dust, gas and fumes are inhaled for a long time and accumulate in the lungs. While carbon, tin, iron, aluminium pose a low level of risk, cadmium, chromium, chromium, lead, vanadium, manganese, mercury, molybdenum, nickel, titanium, zinc, mercury, molybdenum, nickel, titanium and zinc, which are among the metals that workers in welded manufacturing workshops are affected by dust, gas, fumes and oxides, cause much greater health problems and permanent diseases because they create irritant and toxic effects. In summary, dust, fumes, gases and vapours, which are frequently encountered in welded manufacturing workshops and which enter the body by inhalation, cause irritation in the respiratory tract due to the presence of the above-mentioned chemicals and cause permanent diseases if inhaled at high concentrations for long periods of time. A similar effect is seen in the eyes and health problems such as irritation, conjunctivitis, keratitis and allergies occur in the eyes.

How do hazardous particles in welding fumes settle in the body?

Particles of 10 microns and larger settle in the nasal mucosa and throat, particles of 4.7-5.8 microns in the larynx, particles of 3.3-4.7 microns in the trachea and main bronchi, particles of 1.1-3.3 microns in the secondary and tertiary bronchi, and particles smaller than 1.1 micron in the alveoli. Particles of all sizes are present in welding fumes.

How to protect against welding fumes?

According to all international regulations, welding fumes must be absorbed without inhalation as soon as they appear. It is essential for human health and the environment that such local extraction systems are mobile or wall-mounted and have appropriate filters. The hood at the end of the suction arm connected to the suction system should be at a maximum distance of 30 cm from the point where the fume is produced and the fume should be absorbed before it spreads to the environment and inhaled. The filters used in the fume extraction system must be of a quality that can hold the particles in the welding fume in the most efficient way. "Local suction" is not possible, especially in enterprises that weld large parts. We cannot expect any welder to move this suction arm continuously during long welding processes. In workshops where only local suction is used, when these tools are not used properly for this reason, the smoke is dispersed throughout the workshop environment and all employees are affected by the fumes. As a result, workers in the workshop, which is not inspected, continue to be poisoned. Together with local suction systems, devices that continuously circulate and filter the workshop air are essential. Along with these devices, welder head masks with waist motorised filter equipment should be used by welders. Aluminium dusts are explosive. A suitable suction/filtration system is essential. Bottom suction cannot be used in MIG-MAG and TIG welding applications. In this type of suction process, since the system will also absorb the protective welding gas, the welding quality deteriorates and more gas is consumed than it should be. It brings additional burden to the national economy. Another application, fume suction welding torches, can only work up to a certain welding amperage and in certain positions, although not completely. But in general, we do not recommend the use of such products in manual welding applications. These torches can be used successfully in automation and robots.
In order to be protected from welding rays; welders must use leather clothes and their skin must not be exposed to this ray. Welding areas must be divided with ISO EN 25980 certified curtains. The welding masks used must at least have certificates in accordance with EN 379: 2009-07 standards, CE, DIN and EC-Type Examination Certificate certificates must be questioned. Optical classes must be at least 1/1/1/1/2. Is it objectionable to throw the absorbed smoke out of the environment without filtering it? Firstly, throwing these particles into the atmosphere without filtering them harms the environment. Some hazardous particles in welding fumes damage plants and underground water resources. In addition, these particles reaching the fan system without filtering will cause corrosion and accumulation on the fan blades. In this case, the fan balance will be disturbed very often and the suction performance will decrease as the aerodynamic structure of the fan will deteriorate. Apart from these; it should not be forgotten that there are burns at the points where welding fume particles accumulate.

Another issue is heating costs. Especially in the winter months, when you throw out the air absorbed by filtering or not from the east, you actually throw out the ambient air that you actually heat. This increases your heating costs. To give an example; an average flow rate of 1000 m³/hour is required in a suction arm. This amount is the ideal ratio for sucking the welding fume in a healthy way. If we consider that there are 10 suction arms in the enterprise and the air sucked by these arms is directly discharged, you will discharge 10.000 m³ of heated air every hour. Assuming that they work 5 hours a day on average, 50.000 m³ of air will be discharged into the atmosphere every working day. However, if a quality filter system is used, the sucked air can be filtered according to international standards and can be returned to the environment and in this case, a very high saving is achieved in heating costs.
What type of filter should be used in the fume extraction system? Our recommendation for welding fume filtration is that the main filter should be at least F9 (EN779:2012), ISO ePM1 85 % (ISO 16890). If you choose a system with a "cleanable cartridge filter", the filter lifetime will be longer. Thus, operating costs will also decrease. If you buy a model with automatic cleaning, you can get more efficiency from the filter. The investment cost may be high, but it saves operating costs.

Should an activated carbon filter be used?

Activated carbon filters are useful for trapping gas and odour molecules. After the main filtration, passing the air cleaned from particles through an activated carbon filter retains gas molecules. However, the market mostly uses fibre filters impregnated with activated carbon water. These filters lose their function in a very short time. Our recommendation is to use granular activated carbon filters. It should not be forgotten that; not every activated carbon holds every gas molecule. The right type and amount of activated carbon granules should be selected according to the type of gas and odour.

 

HiVent Technology, 04/10/2024, Ankara