What is dust/fume?
The term of dust/fume applied in this context describes the amount of dispersed, firm particles in the air, which are produced among others during mechanical processes such as welding. In general, one distinguishes grit and fines. Fines can be further classified into categories E-dust (dust which can be inhaled), A-dust (alveolar dust) and U-dust (ultra fine dust).
In general dust/fume below a particle size of 10µm is characterized as fines. Additionall, welding fumes, soldering fumes and oil mist are part of this category. Since their particle size is smaller than 1µm, they belong to the fraction of A-dust particles and require particular hygienic attention.
How is dust/fume produced?
In welding technology, dust/fume and equally hazardous substances are produced due to the use base materials filler materials impurities
Why is dust/fume dangerous?
In general, every kind of dust/fume can lead to respiratory diseases (bronchitis, obstructive bronchitis)resulting from the inhaling of dust in a high concentration and during a longer period. Dust/fume is particularly dangerous if it contains hazardous substances.
Framework regulation Hazardous Substances Ordinance (HSO)
Come into effect on January 1st, 2005, the Hazardous Substances Ordinance (HSO) restructures the occupational safety for activities involving hazardous substances as implementation of several EC directives. Welding fume is considered a hazardous substance, thus the HSO applies. Particles contained in welding fume are inhalable and respirable and, in case of chromium-nickel steel, carcinogenic. The HSO states "Dusts shall be collected and disposed of safely as far as possible at the place where they are escaping or developing. The air extracted shall be conducted in such a way that as little dust as possible passes into the worker's breathing air. The air extracted shall only be returned to the working area if it has be adequately cleaned.
Equipment to separate, collect and precipitate dusts shall be in accordance with the state of the art. When these devices are first put into operation, it shall be checked that they are adequately effective. At least once a year the devices have to be inspected with respect to their proper functioning, serviced and, where relevant, repaired. The results of the inspections [...] shall be retained."
Return of the air for activities involving carcinogenic substances
According to the HSO:"If activities involving hazardous substances that are carcinogenic, mutagenic and toxic to reproduction of category 1 or 2 are performed in a working area, the air extracted there shall not be returned to the working area. This shall not apply if the air has been adequately decontaminated of such substances using processes or devices recognised by the authorities or the statuory accident insurance institutions. The air shall then be conducted or cleaned in such a way that hazardous substances that are carcinogenic, mutagenic and toxi to reproduction do not pass into the breathing air of other workers.
If the welding fumes contain carcinogenic parts - such as nickel compounds or chromates - the exhaust air has to be guided outside. In exceptional cases, the cleaned air can be returned if the requirements of the TRGS 560 (Technical rules for hazardous substances air return when handling carcinogenic substances) are fulfilled. According to this, the concentration of hazardous substances in the air which is returned into the working area (returned cleaned air) may not exceed a tenth of the former TRK (technical guideline concentration) value.
Tips for users In order to fulfill the requirements, the operator has mobile dust extractors as well as central stationary devices at hand. The dust extractors certified by IFA (formerly BGIA) in accordance with the international standard DIN EN ISO 15012-1 and the central devices corresponding to TRGS 528 fulfill the legal bases.
|Chemical symbol||Exposure limit (mg/m³)|
|Chromium III compounds||Cr||2|
|Chromium VI compounds||CR (VI)||0.05|
While being primarily used for military services in the beginning, nowadays lasers have become a useful tool for industry, medicine, communication, science and entertaining media.
The biggest share of that is in the industrial field, namely the treatment of materials by lasers.
Reshaping, Separating/Abrading, Connecting, Coating, Marking, Printing
The distribution of materials is as follows
Fume and dust emissions from laser processes
We distinguish between two different kinds of emissions. Metallic dusts often appear in the form of aerosol (solid or liquid particles) that gets mixed up with the surrounding air or other gases while the treatment of organic materials like wood or artificial ones like plastic cause a thermic reaction, called pyrolysis.
1. Working on Metal
Particles and gases like metalloxidic dusts are the main part of emissions. Nitrogen oxides and ozone often can be found besides several genetically hazardous and carcinogenic substances like chrome, nickel, iron oxide, aluminum, mangan and zink.
2. Working on other (mainly organic) materials
Often the highly energetic laser treatments of these materials cause a pyrolysis. Chemical and physical reactions lead to the emission of harmful substances. They can be highly toxic and caustic. Especially the treatment of halogen compounds like PTFE and PVC are hazardous. Hydrochloric and hydrofluoric are the the results which are extremely dangerous and caustic. Equally problematic is the treatment of products that were treated with fire retardants leading to emissions of dioxins and furans.
What are welding/cutting smoke/fumes?
Welding smoke and fume are toxic metal smoke/fumes produced during welding operations. They usually have different compositions, depending on the metals that are used for welding. Therefore they contain several contaminants.
It is important to differentiate between the welding fume and the pulverized coal. 95% of the welding fume addict to the filler material as the conductor or the electrode. Pulverized coal is different to welding fume. Here it is the other way around: 95% of the pulverized coal depends on the material you cut.
Attention should be paid to welding fume which is no gas but rather basically particle. This is the genuine risk at a work place.
Some of the most toxic are: Aluminium, Beryllium, Cadmium oxides, Chromium, Copper, Fluorides, Lead, Manganese, Iron Oxides, Molybdenum, Nickel, Vanadium, Zinc Oxides, Carbon Monoxide, Hydrogen Fluoride, Nitrogen Oxide, Ozone and Hexavalent Chromium!
Welding and cutting smokes/fumes pass our lungs and thus the whole body. We inhale them with the air we breathe.
• Irritation of eyes, nose, and chest
• Shortness of breath
• Fluid in the lungs (Edema)
• Inflammation of the lungs (Pneumonitis)
• Loss of appetite
• Nausea / Vomiting
• Chronic lung problems (such as Bronchitis, Pneumonia, Asthma, Emphysema, etc.)
• Lung Cancer
• Cancer of the Larynx
• Cancer of the Urinary Tract
• Parkinson disease
• Skin diseases
• Hearing Loss
• Gastritis, ulcers of the stomach
• Kidney damage
• Heart disease
The most dangerous and frequency of gases is active oxygen. This is most damaging. But it is possible to avert the accumulation. For this purpose it is essential to partition the work place. To eliminate the acquisition of the UV radiation it is important to cover or to put away reflective objects. This is feasible with vertical blinds.
Ventilating a complete workshop does not prevent the welders breathing zone from hazardous substances.
Local point extraction is the most effective method. The hazardous substances are captured right at the source/torch before they reach the welders breathing zone. This is the only guarantee of a sufficient protection to provide clean breathing air for welding and cutting applications.
General ventilation like open roofs, open doors and windows or simple roof and floor fans only spread the hazardous materials all around the workplace and working halls.
In co-operation with local German and European Health and Safety Organizations we recommend the following approach to protect workers according the legislation according to DIN and EN- ISO norms/laws.
One of the most important tools to handle an adequate extraction solution is the German/ European guideline “Schweissen ohne Rauch” (Welding without smoke) of the German association of machine manufacturer. (VDMA)
This guideline provides some important inputs how to handle a proper filtering and extraction system. The VDMA worked out these inputs together with the European administration for Health and Safety according to the most important laws, standards and norms:
TA Luft (Technical Guideline of clean air)
TRGS 900 (Technical Guideline for hazardous substances)
BGR 220 (Welding smoke guideline of the administration for Health and Safety)
BGR 121 (Ventilation guideline of the administration for Health and Safety)
Gefahrstoffverordnung (GefStoffV) Ordinance on Hazardous Substances
Most important according the BGR 121:
Paragraph 3.1.1 General information:
The air of the breathing zone at a work place must have a quality which is not dangerous or hazardous to the workers health.
Paragraph 3.3.2 Action to protect:
The employer has to construct the working application according to the “(GefStoffV) Ordinance on Hazardous Substances“ in a way that no dangerous gases, smokes, fumes or dust could be discharged into the working area. According to the technical possibilities!
Paragraph 126.96.36.199 Collection/Extraction of the emissions: If it is not possible to keep the working environment of a working application free of gases, smokes, fumes or dust, you need an adequate extraction/filter system to capture all hazardous substances directly at place of production and delete them without an danger for humans and environment. According to the technical possibilities!
Paragraph 188.8.131.52 Room ventilation
If it is not possible, according § 184.108.40.206 to extract directly at place of production you need additional ventilation actions to assure clean and fresh air. According to the technical possibilities!
Ventilation systems according to these requirements are complete room ventilation- or filtering devices providing an effective changing or attenuation of the air in a workshop. Completely and/or partly.
The given technical possibilities:
Today it is possible to filter nearly all toxic welding/cutting smoke/fumes according to DIN EN ISO 15012 (Separation of welding fume according welding fume class W3) and recalculate it back into the working environment.
A certification of a filter unit according to DIN EN ISO 15012 ensures the user’s security. The duct collection efficiency of the filter units is > 99% corresponding to the welding fume class W3.
|Manganese (damages nerve system)|
|Carbon Monoxide (blocks oxygen)|
|Nitrogen Oxide (toxic)|
|Vinyl Chloride (carcinogenic)|
|Acid Blue (blocks oxygen)|
|HCl Vapor (toxic)|
|Propenal (highly toxic)|
|Methyl methacrylate (irritative)|
|Phenol (toxic and caustic)|
GlossaryIrritative – Irritation of mucuous membranes by inhalation of laser emissions. Primarily caused by reactions of the nervous systems. No longterm damages of metabolism or cells.