Why is welding fumes dangerous?

There are many substances harmful to health in the smoke generated during the welding process.

Welding fumes

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 welded, residues such as oil, grease and coatings such as paint, galvanising, etc. 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, particles and vapours of metals such as zinc, copper, cadmium, lead and fluoride and chloride based gases are formed 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 through the respiratory tract. 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 concentration in the working environment in welded manufacturing workshops and 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 oral and nasal mucosa can occur. In addition, various damages may occur on the central nervous system, kidney, liver, blood-forming system and bone structure 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 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 as 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 chemical substances mentioned above 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 fume hazards?

According to all international regulations, welding fumes must be absorbed without inhalation as soon as they emerge. It is necessary for human health and the environment that such local suction systems are designed as mobile or wall type and have appropriate filters.

The hood at the end of the suction arm connected to the suction system must be at a maximum distance of 30 cm from the point where the fume is generated and must be extract before the fume spreads to the environment and is 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 fume extraction" is not possible, especially in enterprises that weld large parts. We cannot expect any welder to move this fume extraction arm continuously during long welding processes. In workshops where only local extraction is used, when these tools are not used properly for this reason, the fume is dispersed throughout the workshop environment and all employees are affected by the fume. As a result, workers in the workshop, which is not inspected, continue to be poisoned.

Together with local extraction systems, devices that continuously circulate and filter the workshop air are essential.

Along with these devices, welder head masks (PAPR) with waist motorised filter equipment should be used by welders.

Aluminium dusts are explosive. A suitable suction/filtration system is essential.

In MIG-MAG and TIG welding applications, fume extraction from the bottom with the welding table is not always possible. In this type of suction process, since the system can also absorb the protective welding gas, the welding quality may deteriorate and more gas is consumed than it should be. It brings additional burden to operating costs.

Another application, fume-extraction on welding torches, can only work up to a certain welding amperage and in certain positions, although not completely. In general, however, 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 should at least have documents in accordance with EN 379: 2009-07 standards, and the ownership of CE, DIN and EC-Type Examination Certificate documents should be questioned. Optical classes must be at least 1/1/1/1/2.

Is it objectionable to throw the absorbed fume out of the environment without filtering it?

Firstly, discharging these particles into the atmosphere without filtering them harms the environment. Some hazardous particles in welding fumes damage plants and underground water sources. 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 deteriorate 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 winter months, when you throw out the air sucked by filtering or not, you actually throw out the ambient air you have heated. 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 rate 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 for an average of 5 hours a day, 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 reintroduced to the environment and in this case, a considerable 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 your 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 retaining gas and odour molecules. After the main filtration, passing the air cleaned from particles through the activated carbon filter retains gas molecules. However, fibre filters impregnated with activated carbon water are mostly used in the market. 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.

Should the system we will purchase be W3 certified?

The German Institute for Occupational Safety (IFA) has classified welding fumes into 3 classes according to their harmful content. Fumes from welding unalloyed or low alloyed metals are classified as W1, fumes from welding metals containing between 5%-30% chromium and nickel alloys are classified as W2 and fumes from welding metals containing more than 30% chromium and nickel are classified as W3.

Welding fume extraction system manufacturers can obtain W2 and/or W3 certificates for their products by entering IFA tests. Unfortunately, this certification process cannot be realised in our country. The certification of the products by sending them to Germany IFA laboratories is both very long and very costly.

Welding fume extraction systems manufactured in accordance with ISO 21904-4:2020 standard meet W3 requirements. HiVent branded products are manufactured according to this standard and other standards.

The fume extractor I bought lost its suction power after a while. What can I do?

Firstly, if it is a product with a cleanable filter, you must clean the filter frequently and properly in accordance with the manufacturer's instructions. If it is a product with automatic cleaning, either there is a problem with the cleaning system, there is a problem with the compressed air supply or the filter has reached its saturation point and needs to be replaced. If you have a product with non-cleaning filters (mechanical), you should replace the filters immediately. If the suction performance is still poor, please contact the manufacturer. There may be other problems, especially with the fan.

Another consideration is that the more filters that are retrofitted to a fume extraction system, the lower the extraction performance can be. Also, similar problems may occur when the original filter is not used. In the design phase of such systems, appropriate system design and filter selection are carried out by considering the flow rate/pressure curves of the fans used. Some subsequent interventions or inappropriate filter use affect the machine performance.