When welding, it is crucial to take adequate precautions not only in regard to fire hazards but also to prevent the inhalation of poisonous fumes. Welding fumes usually contain metallic oxides, fluorides, and silicates, among other potentially harmful mixtures depending on the type of metal being welded.
How are the fumes formed? Welding fumes form when metals (either coated or uncoated) are heated above their boiling points to the extent of the vapors condensing into fine solid particulates.
The Welding Hazards to Consider
Fumes or vapors can come from residues and coating on different metals that are being welded. It is crucial to take extra precautions since some coatings can have extremely toxic effects. The highly risky ingredients are such as
- Zinc coating on galvanized steel which vaporizes to produce toxic zinc oxide fume
- Vapors from solvents and paints
- Cadmium plating
- Plastic coatings
- Lead oxide on primer paints
When welding zinc-coated steel, you need to be extra careful to avoid inhaling the fumes. When you arc weld galvanized steel, the heat produced by the welding arc is high enough to vaporize the zinc coating. This results from the variation in boiling points between zinc (lower) and steel. Proper precaution is needed when handling these coated metals, as their fumes can lead to serious conditions like the Metal Fume Fever.
More about the Metal Fume Fever
Also known as brass shakes, zinc shakes, brass founders` ague or metal dust fever, metal fume fever is a condition resulting from too much exposure to harmful chemicals found in metal fumes. Some of the chemicals that lead to metal fume fever include zinc oxide, magnesium oxide, and aluminum oxide, among others, which are byproducts of fumes that result from the heating of metals.
Brazing, welding base metal, plating, or even soldering can also lead to metal poisoning as a result of exposure to copper, zinc, lead, or cadmium. Some of these chemicals like cadmium can even lead to unconsciousness.
The exposure to harmful chemicals that cause Metal fume fever more often than not arises from hot metalworking activities that involve melting and casting of galvanized metals, zinc alloy, brazing, and soldering. Cold sanding can also lead to metal fume fever, especially when working on a high-risk metal.
The best way to prevent metal fume fever is to avoid direct contact with toxic fumes, working in well-ventilated areas, and improving on personal safety measures. You should always wear respiratory kits when working on potentially sensitive metals.
How do I Remove Coatings?
Removing coatings can play a vital role in reducing the concentration of harmful metallic components. The removal of coatings on your base metal will improve the quality of your weld while also minimizing the fume.
To remove coatings, you can use stripping products and even use them on residues before commencing on your welding operations. When removing extremely toxic coatings, we advise using a slurry vacuum removal mechanism. However, you should avoid grinding coatings since the resulting dust might be toxic if inhaled.
Common factors that Affect Welder Exposure to Fumes
- The type of welding technique plays a huge role in determining the amount of fumes produced
- Factors such as the welding rod`s composition also play a part in fume emission
- The base metal and filler metals should be made from non-toxic materials or have their coatings removed.
- Always check on the coatings to determine the best removal option
- Weld on clean surfaces without coatings and stay upwind whenever you weld outdoors.
Protecting Yourself from Toxic Fumes when Welding
Most likely, you will get assignments that require you to weld with pot metal. But as noted earlier, this metal has its fair share of problems when it comes to welding. Due to its mixed nature, pot metal will not behave like the usual metals you are accustomed to in your everyday welding life.
A wrong move with pot metal can be disastrous to your project.
Although this metal has a low melting point and might contain zinc – which emits toxic fumes when welded, you can still use some tricks to accomplish your welding project.
The first thing you need to do is to TIG-weld the pot metal. For starters, in this process, you use the heat generated by an electric arc. The high temperature is applied between the metals you want to join. This process requires some skills and the right equipment.
However, if you have adequate experience in welding aluminum, then TIG welding will not be such a big challenge to you. The reason is simple: pot metal is quite similar to aluminum, and thus the approach you use to weld aluminum is the same you’ll use to TIG-weld pot metal.
When you start the actual welding, ensure you work slowly using low-temperature settings. Remember, pot metal has a low melting point, so use the same approach you’d use if you were welding aluminum. Always keep the temperatures low otherwise; you might quickly melt the piece you are trying to work on.
Don’t weld non-stop. Doing this can still melt your piece. Instead, work in short intervals of around five to ten seconds. This practice gives your parts and the pot metal sufficient time to cool down. Most importantly, don’t allow the pot metal to heat too much; as soon as it starts to flow, you have to stop welding and let the metal cool down.
Emergency Steps after Inhaling Welding Fumes
No matter how experienced or prepared you might be, you might find yourself inhaling welding fumes accidentally. It could be the incorrect use of a fan at the warehouse or getting too close when welding small surfaces. Due to this, it is crucial to have proper understanding of the emergency steps to take when you inhale toxic fumes when welding.
Move away from the Welding Area
The best precaution after inhaling toxic fumes is to move as far away from the weld location, especially when welding in closed areas. Move to an area with adequate fresh air supply, and breathe in and out as deeply as possible. This will help to relax your lungs and reduce breathing difficulties.
Take in Fresh Water
Water helps to clear your throat and leaves you feeling revitalized after seconds of intense clogging. You can take warm or cold water, although cold water is preferred since you can take it in fast enough to refresh your system. Some fumes might leave you feeling dehydrated or overwhelmed due to persistent coughs. Drinking water will help ease the pressure.
Receive professional Assistance
A fume inhalation emergency should not be downplayed or underestimated. If you want to avoid follow-up conditions that can prove toxic, we recommend seeking immediate assistance from your physician. Have a professional checkup will help determine the best cause of action or medication. You can inquire from your workplace nurse or healthcare provider on the best medication to treat the emergency.
Each welding technique comes with its own pros and cons. The best way to reduce the impact of welding fumes is to ensure you clean up the coating thoroughly. Metal additives like cobalt, titanium; copper, hex chromium, nickel, and manganese are usually present in mild steel. To avoid inhaling these potentially toxic chemicals, it is advisable to wear a protective mask all the time when welding steel.
Metal fume fever can be avoided by welding in well-ventilated spaces. Remember to check on your positioning during welding to avoid inhaling toxic fumes when working on tight areas. If you are welding outside, we recommend always checking on wind direction to determine how you will position the arc.
The best way to prevent the inhalation of toxic fumes is to prioritize safety in the workshop. Always put your face mask on and never shy from seeking alternative ventilation methods to boost air circulation at your workshop. In the event of inhaling toxic fumes, leave the work area as quickly as possible.