Explanation W3
What is W3?
W3 is a certification by the IFA (Institute for Occupational Safety of the German Social Accident Insurance) and is required for safe extraction of welding fumes. Since 2018, the WHO has classified welding fumes as definitely carcinogenic to humans (IARC 118,2018), making almost no distinction between processing low-alloy and high-alloy steel. In Germany, welding fumes from processing high-alloy steels must be extracted and filtered using W3-certified equipment (TRGS 560).
The degree of separation indicates a filter’s performance. Welding fumes are classified into so-called W classes. The limit values for harmful particles depend on the processed materials and the used welding process.
Particles in welding fumes have a size of less than 1 µm. From a size of less than 10 µm, the particles are respirable, while below 0.1 µm they are considered nanoparticles. The concentration of pollutants produced during welding is carcinogenic according to the Technical Rules for Hazardous Substances (TRGS). Natural human filters, such as cilia or nose hairs, cannot catch them.
The recirculation of air into the work area during welding is generally prohibited according to the Ordinance on Hazardous Substances. Unless it is done with a filter extraction system that is certified in accordance with DIN EN ISO 21904 “Occupational safety and health in welding and allied processes” Class W3. In this case, the air can also be recirculated after extracting carcinogenic pollutants such as chromium or nickel.
W3 filters certified by IFA separate fumes and dust from high-alloy steels with a separation efficiency of 99%. The air filtered by the certified equipment can be returned to the ambient air. The filter system has to be tested at least once a year to ensure effective operation.
|
Class |
Separation efficiency |
Usable for |
|
W1 |
> 95 % |
Unalloyed or low alloy steel |
|
W2 |
> 98 % |
Alloy steel with 5 – 30 % nickel and chrome parts |
|
W3 |
> 99 % |
High-alloy steel with > 30 % nickel and chrome parts |
TRGS560 and TRGS528 are not only used for the evaluation of classic welding, but also for all thermal processes in which high-alloy steels are processed, such as welding, cutting and laser marking. The tests by the internationally recognized Institute for Occupational Safety confirm the degree of separation and thus the safety and performance of welding fume separators. TBH fume extraction systems have a W3 marking.
DIN EN 21904 evaluates the machine and filter change. Our air filtration systems are labeled ‘DGUV tested’ and are included in the positive list of the IFA as tested devices.
Up to a particle size of 100µm, the limit value for respirable dust determines the required filter performance. If the limit value is above 10 milligrams per cubic meter, the maximum value, based on a particle size of 10µm, is 1.25 mg/m³. Systems with H13 filters have a sufficiently high degree of separation even without the W3 test. The systems must be checked at least once a year for the effectiveness of the filters to protect the employees.
Due to their high degree of separation, TBH filter and extraction systems of the H class and with W3 labeling of hazardous substances can be used if the discharged air is to be returned to the working area.
Do you have any further questions?
Please call us at +49 (0) 7082/9473-0 or send us an e-mail to info@tbh.eu.
