Reducing Risk When Welding and Brazing
Because welding and brazing are activities that involve the use of a high-powered torch, common sense would tell you that they are inherently dangerous. Direct contact with the flame or with the metal parts being heated can cause severe burns before a worker even realizes what’s happening.
But burns are only the most obvious hazard associated with welding and brazing. In this article, we’ll examine other potential dangers associated with welding, brazing, and similar activities. Those hazards include damage to the eye from exposure to bright light and flying debris, hazards associated with the fumes that are often created while workpieces are being heated, and the potential for triggering fires or explosions with welding equipment. We’ll also examine steps that should be taken to mitigate these hazards.
Types of welding
Welding is essentially the process of joining two metals together by selectively melting them and a filler metal so that they will harden into a strong, permanent joint. There are two basic forms of welding. Fusion welding uses heat by itself to make the joint, with the heat source provided by generating an electric arc, burning a gas such as acetylene, or a triggering chemical reaction (known as thermit or thermite welding). As the name implies, pressure welding adds a strong amount of localized pressure along with the heat source.
Brazing is a similar process, except that the two metals are joined by melting only the filler material. Plasma and oxy-fuel cutting, which use torches to cut metal by melting it, is also similar to welding.
Hazards to the eye
If you’ve ever been in a pitch-dark room and someone turns on a bright light, you may have been blinded momentarily. Some types of welding emit intense light that creates a similar, but far more powerful, impact on the eye. That effect is known as radiant energy, and exposure to it can cause permanent damage to vision.
To protect the eyes from that radiant energy, welders and workers who may be observing or helping the welder need to wear eye protection. Depending upon the degree of radiant energy produced by the specific task, that may include anything from tinted safety glasses to welding helmets or face shields. That protective gear usually contains a filter lens to block out the radiant energy. A darker filter carries a higher shade number because it is able to block out more radiant energy. The shade also allows the welder to see the workpiece more clearly.
In many situations, welding, brazing, or cutting may cause fragments and chips to break off the surface and edges of metal that is being worked. In those cases, the protective equipment should include some type of side protection to keep that debris from flying into the eyes.
Smoke and fumes
The intense heat involved in the welding process often produces smoke, along with chemical fumes that may not be visible. Depending upon the materials being joined and the types of welding that is being used, that smoke and fumes may contain a wide array of hazardous gases and byproducts, from airborne metals to compounds such as nitric oxide, phosgene, and hydrogen fluoride. Some materials, such as the chromium that can be found in stainless steel and chromate coatings, are changed by welding into a highly toxic hexavalent state that can damage tissue and may even lead to certain cancers.
Being exposed to smoke and fumes for a short period can cause uncomfortable irritation to the eyes, nose, and throat, and even make a worker dizzy or nauseous. Longer exposures can damage the lungs. Certain types of fumes have been connected to damage to the nervous system and the kidneys, as well as to stomach ulcers. Some gases can even displace oxygen, leading to asphyxiation or suffocation when work is being performed in confined spaces.
Protecting workers from the dangers of fumes can involve several steps, the first of which is ensuring adequate ventilation. Don’t assume that working outside or in a large room will provide enough ventilation. Instead, make sure there is supplemental ventilation. Workers can also reduce the hazards by positioning themselves in ways that allow smoke and fumes to drift away from them. Indoors, fume hoods and exhaust systems can draw hazardous smoke and fumes away.
If the work involves hazardous materials, steps must also be taken to prevent toxic materials from accumulating or displacing oxygen. Special respirators may be appropriate when welding or coating materials with potentially toxic coatings, or when performing work in a confined space that cannot be easily ventilated.
Fires and explosions
Welding equipment produces extremely high temperatures. For example, some arc welders can generate heat of more than 10,000 degrees Fahrenheit. That creates a significant risk for igniting flammable or explosive materials in the immediate area.
Before beginning work, the immediate area should be inspected to identify any potentially flammable materials. Metal sheets or other fire-resistant materials can be placed between the word area and flammable materials to reduce the possibility of ignition. If the floor is not made of a fire-resistant material such as concrete, steps should be taken to protect it.
Appropriate fire suppression equipment such as fire extinguishers or buckets of sand should be within reach. In some cases, it may be advisable to designate an employee to stand and watch for fires while work is proceeding.
Personal Protective Equipment
Welders and those performing similar work (or working in the immediate area) should wear clothing and personal protective equipment that shields them from the heat and other hazards of the particular task and welding method. That may include fire-retardant clothing, heavy gloves, safety shoes, helmet or hair protection, and protective leggings. Eye protection is also a must, both for reducing the effects of radiant energy and stopping any chips or fragments that may fly off the workpieces. Workers should also not carry flammable or explosive items such as butane cigarette lighters.
Watch out for other workers
Steps should also be taken to provide for the safety of workers in adjacent or nearby areas. Before beginning the work, assess the potential hazards and identify strategies for mitigation. One common technique is to use screens to block off the area where welding or similar work will take place, reducing both the radiant energy and the potential for flying debris. Finally, once the work is complete, warning signage should be placed in the area so that workers do not handle or come in contact with welded materials until they have cooled to a safe temperature.