Keep A-head of Hazards
By Dan Birch
Welding carries with it a host of potential hazards that demand careful consideration even before arc meets metal.
Depending on the welding process employed, issues such as ergonomics, noise, electric shock, bright light, ultraviolet (UV) radiation, toxic fumes and gases, and heat/fire/burns may all come into play, notes information from the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ontario.
That demands an array of personal protective equipment (PPE) be in place, such as helmets, gloves, jackets, respirators and more. Although all PPE is important, at the core is a need for protection from the top.
The welding helmet provides the basic, necessary defence from which tweaks for taste or work-related need can flow. “The helmet is probably the most significant investment a welder is going to make,” suggests Bill Gardner, product manager for Miller Electric Mfg. Co. in Appleton, Wisconsin.
It may be that taking a passive approach, perhaps using a less expensive helmet with fixed filter shades, is all that is needed to safely get the job done. Or it may be that a more modern take on helmets (a.k.a. hoods) with auto-darkening filters (ADFs) will suit demands.
A traditional, passive helmet holds a lens filter with a single shade of protection, allowing users to manually switch to lighter or darker shades as needed.
Compare that to an ADF, which is capable of quickly and automatically transforming from very light to very dark, and vice versa.
“When the welder is looking through the helmet, the filter automatically senses the arc,” explains Jamy Bulan, commercial equipment product manager at Lincoln Electric in Cleveland. One positive of an ADF, Bulan says, is that it eliminates the need for a welder to flip the hood up and down to see the weld.
Katie Twist-Rowlinson, welding and hard hats product manager for Honeywell Safety Products in Smithfield, Rhode Island, agrees. “You don’t have to constantly lift up and pull the helmet down into position. It’s ready to go whenever you are,” Twist-Rowlinson says.
And that is a must for those who weld for a living, not just as a hobby, she suggests. Passive helmets may be ideal for hobby welders who do not spend entire days doing so and who want a lower-priced option, she says, but argues that professional welders “need the efficiency and the time savings that an ADF brings to the table.”
Filter lenses are made of glass that contains a filler to reduce the amount of arc light that reaches the eyes, the CCOHS reports. As for the filter, Bulan says that it is covered by a thin polycarbonate lens to help protect it from welding spark and spatter, thereby enhancing its durability.
The greater the filter shade number, which ranges from two to 14, the darker the filter and the less light able to pass through. Pointing to the Canadian Standards Association’s (CSA) W117.2 standard on Safety in Welding, Cutting and Allied Processes, the CCOHS notes that welding process, electrode size and amount of electrical current are all factors influencing which filter shade is appropriate for the task.
Bulan suggests that “as ADF cartridge prices are coming down, more and more welders are going to the ADF technology.” A typical ADF lasts about 5,000 hours, he says.
Gardner reports that price is also affected by filter switching speed, lens area and the number of arc sensors on an ADF hood. Some lenses “might have two [arc] sensors. Other higher-quality lenses will have four.”
Sensors certainly make sense since they provide a read on the arc’s harmful light, information that triggers the switch from an ADF’s light state to an appropriately protective shade. “Often, welders will be working in awkward positions — out-of-position welding where one sensor might be obstructed by a piece of material,” Gardner says.
“It can affect the performance of the lens switching to the dark state. The more sensors you have on it, the less likely you’re going to have issues,” he advises.
Other factors, such as dead ADF cartridge batteries, improper sensitivity settings or using ADFs in very cold temperatures can also downgrade switching speed and result in temporary flash blindness, adds information from the American Welding Society (AWS) in Miami.
VIEW FROM HERE
After deciding between a passive or ADF helmet, Bulan says another important consideration is viewing screen size. Windows are relatively small compared with a person’s normal field of vision, “so you have to move your head around a lot,” he points out. “Any decrease in movement over time is going to lead to less fatigue [and more] production efficiency.”
A common viewing area for a passive hood is 102 by 108 millimetres (mm); for an ADF, this often ranges from 94 by 35 mm to 97 by 60 mm.
But size is not everything. ADF lens quality, marked by clarity and consistency across the viewing area, is an often-overlooked and under-appreciated feature, Gardner suggests.
Fibre-Metal Products, now part of Honeywell Safety, uses angular dependency compensation technology. This allows “a welder to work in various positions with no shade variation in the viewing area,” says Twist-Rowlinson. “This will decrease eye fatigue and allow the welder to perform better welds for a longer period of time.”
Of course, viewing screen size can add to weight and, in turn, influence user comfort. Noting that his company’s helmets weigh a little more than a half-kilogram, Bulan says most of this is from the ADF cartridge and viewing window.
“As the viewing area gets larger, the weight of the [ADF] helmet gets larger,” he notes. Although the difference between a large and a small ADF may be about 50 grams, every bit of weight counts when wearing a helmet for eight hours.
Helmets that combine eye protection with auto-darkening lens capability are much lighter than older units that had a separate hard hat, face shield and respirator, notes Dave Hisey, volunteer technical committee chair for the CSA’s Safety in Welding, Cutting and Allied Processes standard. “When properly used and equipped, these combination units can greatly improve the air quality breathed by the welder, and since they are lighter, reduce neck strain,” Hisey adds.
As with any PPE, making the right helmet choice will demand looking at both task and environment. “It depends upon what industry, what kind of welding and how much welding you’re doing in a day,” says Twist-Rowlinson.
Take, for example, a Fibre-Metal Products helmet designed with pipe welders in mind. Its compact design allows users to access tight spots where a standard helmet would not safely fit, and the hood comes with the option of a constant-fit rubber headband rather than the traditional tightening ratchet, Twist-Rowlinson says.
Gardner also cites the needs of welders at construction sites. They often prefer a passive hood because of the inevitable wear and tear, as well as the possibility of being dropped from heights. Should this occur, he says replacing an ADF is more expensive than buying a passive filter.
But small features that make a big difference in terms of safety are sometimes more nuanced. “Helmet design has become a game-changing factor that sets a great helmet apart from an average one,” suggests Carrie Mailloux, welding solutions product marketer for 3M Canada Company in London, Ontario. “Providing superior stability, balance and comfort allows welders to focus on the task at hand even in the toughest of conditions,” Mailloux notes.
She says her view is that a helmet introduced by 3M three years ago “radically changed the welder’s ergonomic experience with improved adjustability, protection and ventilation.” Designers collaborated with Western and Chinese medical experts to fashion a head suspension that avoids “vulnerable nerves, arteries and acupressure points — areas traditionally pinched by conventional headbands,” she reports.
Features that promote a tailored fit mean welders do not have to over-tighten the headband, as is commonly done by users struggling to keep traditional headgear on while working in unusual positions, Mailloux adds.
There is also a need to consider the welding work force, and whether or not that is changing.
Consider that PPE makers are now exploring helmet offerings for an emerging segment of the market: female workers. “Welding has long been a male-dominated occupation, but the number of women welders is growing,” says Mailloux.
“Through speaking with women welders, four compelling [graphic] patterns were selected: a rose pattern, eyes looking through purple flames, a vine entwined with barbed wire, and a skull and flowers,” she says of options in 3M’s line. Each helmet in the collection “has an ergonomic, comfortable headband for better conformity to the welder’s forehead, and also accommodates smaller head sizes.”
GOOD AIR IN…
Looks and comfort certainly have their place, although nothing is so immediately vital as breathable air. Powered air-purifying respirators (PAPR) and supplied air respirators (SAR) are the main options, while portable fume extractors and ventilation can address environmental hazards before things get personal.
“The considerations for PAPR or [SAR] welding modes first require an assessment of the hazards or potential hazards, the type of welding, the environment (say, high heat) and other welding-related activities, such as grinding,” explains Bev Borst, technical service specialist for 3M Canada.
The Miami-based AWS defines welding fume as solid particles that originate from welding combustibles, the base metal and any coatings present on that metal. Besides shielding gases, other gases may be created during the welding process or “may be produced by the effects of process radiation on the surrounding environment.”
Describing just how a PAPR cleans a welder’s breathing zone, Gardner says air is drawn in and HEPA-filtered through a battery-powered unit attached to the welder’s lower back. The air is then transported by a tube and released into the top of the helmet. The air flows down the welder’s face and out the bottom of the helmet, creating positive pressure that disperses fumes and gases.
Even with the face protection provided by helmets, the AWS urges welders to always wear safety glasses with top and side protection under their helmets. Doing so will ensure eyes are protected from airborne material even when welders have to lift their hoods, Gardner says, adding that his company offers glasses ranging from clear to shade 5.
Other options, he says, include glasses that protect against UV and glare, which would be of use on construction projects where people may be near, but not directly looking at arc welding, or shaded glasses for use during plasma cutting and oxy-fuel welding. —
The CCOHS notes that “eye injury can occur from the intense light and radiation from a welding arc and from hot slag that can fly off from the weld during cooling, chipping or grinding.”
WELD IN HAND
Just as eyes need protection, so do hands. Joe Geng, vice-president of Superior Glove Works Ltd. in Acton, Ontario, says that welders should bear in mind several factors when choosing hand protection. “What type of welding are they doing?” Geng asks. Gloves designed for metal inert gas (MIG) versus tungsten inert gas (TIG) welding “are totally different in the materials used and construction.”
Bulan points out that TIG gloves are tightly fitted and made of goat skin rather than cow or pig leathers, enabling the welder to better feel the TIG torch and allowing for more delicate manipulations.
Other factors to consider, says Geng, include radiant heat, cutting hazards and durability. His company offers a TIG glove with a three-layer backing, including a non-flammable outer layer of carbon knit that will not burn, char or harden.
“We are seeing new materials being used in welding gloves that give better dexterity and protection,” Geng reports.
Gardner adds that if gloves are “comfortable and offer protection, employees are going to keep them on their hands.” Traditionally, welding gloves have been big, bulky and poor fitting, he says. Today, welders “have the capability of performing multiple tasks while wearing the gloves, whereas before they would just wear gloves to strike the arc,” he adds.
Once welders have their hands and wrists covered, they can turn to other apparel options meant to guard the rest of the body against sparks, spatter and UV radiation. Protective options might include jackets, sleeves, cape sleeves, bibs, aprons, leggings and more.
Bulan says that his company’s traditional flame-resistant cotton jacket is ideal for light-duty, low-amperage MIG and TIG welding. “It’s cooler, but provides less protection” than a heavy-duty leather jacket for overhead stick welding, he reports.
“The higher up you move on the scale, you gain protection, but you sacrifice comfort,” Gardner suggests.
To lessen heat burden, apparel manufacturers often use more than one material in a jacket, such as flame-resistant cotton in the trunk and premium grain leather on the sleeves, upper torso and shoulders.
Gardner says that Miller Electric has a patented material that offers leather-like protection at the weight and comfort of cloth. The carbonfibre material has a silicone coating that makes it feel like cotton, but repel sparks and spatter.
Whatever apparel one buys, Gardner advises that durability of the flame-resistant properties is important to note. While some garments guarantee resistance for the life of the product, others do so for a designated period, such as 25 washings. How that translates into time all depends on how frequently the gear needs to be washed.
Whatever the equipment, giving it a spin before committing to purchase is a good idea, Bulan suggests. For instance, when considering a helmet, try it on and mimic movements and tasks done on the job.
“It is really common sense,” he says, “but it’s amazing how many people don’t try it on before they buy.”
Dan Birch is assistant editor of OHS CANADA.
The Canadian Standards Association (CSA) in Mississauga, Ontario is preparing to release its revised standard on Safety in Welding, Cutting and Allied Processes. It is anticipated that the new version of CSA W117.2-06 will be published in the spring of 2012, says Dave Hisey, volunteer technical committee chair for the standard. The standard will outline minimum requirements and recommendations to protect people who work in environments affected by welding, cutting and allied processes. In addition, it will provide guidance on how best to prevent property damage arising from the installation, operation and maintenance of equipment used in related processes. “European countries tend to divide welding safety into many different parts, and sell a separate standard for each aspect. CSA chose to keep the standard as one,” Hisey says. “The standard is physically small enough so that a welder can keep a copy in his or her toolbox and it is affordable so that all welders can obtain one.” Among the proposed changes to the standard, Hisey cites the following:
– Section 9 — Gas welding, cutting and allied processes have been significantly updated to improve safety. Many of the changes reflect those to Compressed Gas Association standards that are referenced in CSA W117.2-06.
– Section 10.5 — The underwater welding and cutting section has been expanded to provide more safety guidance for welders involved in these activities.
– Section 11.7 — There have been significant losses in Canada following hot work fires caused by a lack of care around spark control. In response, the section has been modified and now requires that all hot work performed outside of a designated area be subject to a safe work permit program.