OHS Canada Magazine

Feature

Hip to be Cool


Stop whining about the cold; get ready to whine about the heat. Summer is just around the corner and that means on-the-job measures must be in place.

Beating the heat is not solely an outdoors issue. If indoors, consider foundries, steel mills, bakeries and glass factories; if outdoors, think construction, road repair, open pit mining and agriculture, notes the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ontario.

Whether inside or outside, too-high temperatures threaten to put health and safety on the line. Hot temperatures may initially illicit responses that seem to have little impact on safety, such as irritability. But the CCOHS advises that as body heat rises, responses grow far more serious.

Moving from a comfort range of 20 to 27 degrees Celsius to the limit of temperature tolerance, at about 35 to 40 C, a worker may experience loss of concentration, more errors, heavy load on the heart, fatigue and the threat of exhaustion.

Imagine the effect on a worker climbing a ladder, standing at a moving conveyor or using a chain saw. Gear to help keep body temperature from rising includes cooling vests, ventilated hard hats, headbands and hydration systems.

Many factors will influence how hot a worker “feels.” Beyond temperature, there is humidity, air movement, physical exertion, time of day, breaks, clothing and sources of heat.

Heat loading is a function of metabolic heat generated, radiant heat, convective heat, conductive heat and evaporative heat loss, says Dan Curts, a certified industrial hygienist with 3M Canada in London, Ontario. “When workers understand the symptoms of heat stress, they are more able to take the necessary precautions to prevent, or at least minimize, the effects,” Curts suggests.

Ray Booska, CEO of Glacier Tek, Inc. in West Melbourne, Florida, would likely count himself encouraged, noting that companies seem to be more interested than ever in protecting workers from overheating. What may be less encouraging is the level of knowledge around other heat-related issues. Keeping cool demands a mix of responses, but a good starting point may be proper hydration.

HIGH ON HYDRATION

Unfortunately, says Booska, “most people are dehydrated. If you don’t drink at least a gallon of water a day, you may be dehydrated.” Of course, not just any liquid will do.

Sodas, energy drinks and alcoholic beverages — despite the contention they are “mostly water” — may not cut it hydration-wise. Booska says that these options may, in fact, create adrenal fatigue.

Dentec Safety Specialists in Newmarket, Ontario suggests there is definite place for electrolyte replacement drinks as part of a hydration program. Many companies remove their electrolyte programs as soon as summer ends or outdoor temperatures cool, but inside heat remains.

For environments such as pulp and paper mills, foundries and bakeries, significant radiant heat is generated, notes a statement from the company. Individuals face the potential for heat stress-related injuries regardless of the time of year and temperature outside, Dentec Safety reports.

Camelbak is looking to help ensure workers have access to hydration on the go. The company has introduced a 1.5 litre, stand-alone hydration system with closed-cell insulation and a neoprene tube cover to keep water either warm or cool for hours, an external fill reservoir and Velcro tube management.

Bearing in mind that workers may need to move with their work, the unit also comes with D-ring attachment points so it can be placed wherever needed.

Having liquid close at hand is often essential. Last year, St. Paul, Minnesota-based Ergodyne released hydration padded tool rig suspenders that can be attached to any of the company’s tool belts. This allows workers to keep water at the ready.

HEAD OF THE CLASS

Keeping a step ahead of the heat requires paying attention to, well, the head. Most people know that covering the head is critically important to keeping warm, but looking to the top also figures prominently when it comes to keeping cool.

In March, Ergodyne released additions to its line of products: an evaporative bandana with cooling towel, and an evaporative triangle hat, also with a towel. Just soak in cool water for two to five minutes to activate.

The products feel significantly cooler than ambient air, remain hydrated throughout the day, can be used under helmets, are machine washable and have a tie closure for personal fit, notes a statement from the company.

The patented products feature polyvinyl acetate (PVA) material that keeps workers cool without added bulk and weight. “PVA is hands-down one of the most amazing technologies we’ve ever used,” Tom Votel, CEO and president of Ergodyne, notes in the statement.

Degil Safety Products in Vaughan, Ontario, for its part, offers a deluxe cellulose sweatband. Dip the band in cold water, squeeze out and wear, notes a product sheet from the company. The aid sits in place with the help of a rubber band.

Silver Eagle Outfitters is based in Australia, where people surely know something about heat. The company has a hat that blocks 98 per cent of ultraviolet (UV) radiation. Featuring an eight-centimetre brim, the hat’s absorbent fibre core traps water without becoming oversaturated, and its liner is water-resistant to transport moisture away from the head.

If the idea is to make it in the shade, the company also offers a neck shade that fits securely around hard hat suspensions and ball caps. The machine washable shade drapes to the shoulders and covers the ears. Shoulder cut-outs allow for better positioning around the neck.

Perhaps, more than shade is in order; workers may need shelter.

In February, Ergodyne announced the availability of portable work shelters, including a pop-up series and a seating series.

The easy-to-assemble tents — which boast an approximately three-by-three-metre footprint, are less than 23 kilograms and have a wheeled storage bag for simple transport — are ideal for workers who could fall victim to heat stress illness, notes a company release. The tents “deliver on the rising and real safety concerns surrounding heat stress and UV protection, Votel says.

HEAD OF THE CLASS

Keeping a step ahead of the heat requires paying attention to, well, the head. Most people know that covering the head is critically important to keeping warm, but looking to the top also figures prominently when it comes to keeping cool.

In March, Ergodyne released additions to its line of products: an evaporative bandana with cooling towel, and an evaporative triangle hat, also with a towel. Just soak in cool water for two to five minutes to activate.

The products feel significantly cooler than ambient air, remain hydrated throughout the day, can be used under helmets, are machine washable and have a tie closure for personal fit, notes a statement from the company.

The patented products feature polyvinyl acetate (PVA) material that keeps workers cool without added bulk and weight. “PVA is hands-down one of the most amazing technologies we’ve ever used,” Tom Votel, CEO and president of Ergodyne, notes in the statement.

Degil Safety Products in Vaughan, Ontario, for its part, offers a deluxe cellulose sweatband. Dip the band in cold water, squeeze out and wear, notes a product sheet from the company. The aid sits in place with the help of a rubber band.

Silver Eagle Outfitters is based in Australia, where people surely know something about heat. The company has a hat that blocks 98 per cent of ultraviolet (UV) radiation. Featuring an eight-centimetre brim, the hat’s absorbent fibre core traps water without becoming oversaturated, and its liner is water-resistant to transport moisture away from the head.

If the idea is to make it in the shade, the company also offers a neck shade that fits securely around hard hat suspensions and ball caps. The machine washable shade drapes to the shoulders and covers the ears. Shoulder cut-outs allow for better positioning around the neck.

Perhaps, more than shade is in order; workers may need shelter.

In February, Ergodyne announced the availability of portable work shelters, including a pop-up series and a seating series.

The easy-to-assemble tents — which boast an approximately three-by-three-metre footprint, are less than 23 kilograms and have a wheeled storage bag for simple transport — are ideal for workers who could fall victim to heat stress illness, notes a company release. The tents “deliver on the rising and real safety concerns surrounding heat stress and UV protection, Votel says.

HARD TARGET

Cleveland-based Gateway Safety Inc. has opted to take a hard (hat) look at how best to prevent heat-related illness. Last August, the company introduced a safety helmet that helps minimize heat build-up by releasing heat through an airflow system and six vents along the peak of the helmet.

Weighing in at about a third of a kilogram, the helmet also has a cushioned brow pad to absorb moisture and perspiration.

Curts notes that combatting worker heat stress is among the goals of three types of respirators from 3M. The company’s supplied air respirators can have a cooling valve attached to the airline, which reduces the temperature of air entering the worker’s head top. “This reduction in air temperature helps keep the worker cool even in the hottest of environments,” he says.

As well, many of 3M’s powered air-purifying respirators “are designed to push clean air over the worker’s head and face, thereby increasing the loss of heat by the body due to convection,” Curts adds.

A third type of respirator is the negative pressure elastomeric or maintenance-free respirator. It features a valve that allows “the worker’s hot and humid exhaled breath to easily exit the inside of the respirator,” Curts says.

WELL-VESTED

It may be that variety is the spice of life… and work. Glacier Tek offers numerous cooling vests because there are many types of workplaces, Booska suggests. “Some people work in a mine, others on a boat, others in space. All sorts of scenarios exist and vary widely.”

What is different about his company’s vests, says Booska, is that they are the only phase change product that contains no hazardous chemicals. “Our product is all green, completely renewable, and contains no dangerous or hazardous chemicals,” he says.

In the summer of 2009, Ralston CanSafe announced the availability of a cooling vest for use by construction crews, firefighters, welders and factory workers. The 100-per-cent cotton vest is reusable and should be soaked in cold water for two to five minute to achieve a constant temperature for as long as three days, reports the company, based in Fergus, Ontario.

And a new zip-front vest from Silver Eagle Outfitters is also activated by using tap water for a few minutes. It fits over clothes and can be worn directly against the skin.

The vest’s wicking liner features a moisture barrier that forms a water-repellent shield to help keep the wearer dry and comfortable, notes information from the company.

Booska reports that he is seeing products that use water crystals or sodium polyacrylate as declining in popularity.

Cooling depends on evaporation, he says. “That evaporation fails in most workplace scenarios due to humidity, other protective gear, over-garments, etc.,” Booska notes. With renewable phase change material, a product “stores energy and actually provides hours of cooling regardless of the ambient temperature, humidity or other clothing requirements.”

CIRCULATING COMFORT

One way to get evaporation going — at least on the inside — may be by getting the air moving. Serco, based in Carrollton, Texas, has announced the launch of a high-volume, low-speed fan series. The fans are used to “slowly move a massive column of air, creating a deep horizontal floor jet that circulates the air in large spaces.”

The gentle breeze breaks the moisture-saturated boundary layer on the skin. In humid environments, the fans help to exhaust air and prevent moisture build-up, Serco reports.

When the temperatures are lower, the fans take the opposite approach, running in reverse to circulate the hot air trapped at ceiling level.

Whether inside or outside, everyone is intimately aware of that sticky feeling: sweat has caused clothing to cling to the body, proving uncomfortable and distracting. Ergodyne’s new multi-band is made of soft, stretchable, fast-wicking polyester microfibres.

Meant as much to address the cold as the heat, the band can be worn in more than 10 work-ready configurations. Placed under hard hats and helmets, it provides both moisture management and anti-bacterial performance.

3M, for its part, offers disposable coveralls that feature a patented breathable back panel. “Most disposable coveralls are non-breathable and do not allow the worker’s metabolic heat to escape,” Curts says. “This can lead to severe heat stress in very short periods of time.”

WIPE DOWN, BUNDLE UP

Sometimes, it comes down to a well-timed wipe. Towels made of PVA material serves to hold moisture, but without feeling heavy. Worn around the neck, the towels offer quick access to heat relief throughout the day.

Also available on the market are snap-on bands that can hook onto hard hats. One side of the band is cotton terry cloth to absorb perspiration from the forehead, while the other side is a cotton layer that allows the encased absorbent polymer crystals to get to work.

Want it cooler still? Try placing the band in a cooler with ice water for a minute or two.

Perhaps bundling up will help bring that heat down. Available from Silver Eagle Outfitters are cooling blankets that remain lightweight even when activated.

The company reports that the water-repellent liner acts as a conductive layer to pull heat from the body, keeping the user cool and dry. By drawing away heat — rather than shocking the body with uncomfortable cooling — the quilt “is a safe and comfortable solution to heat stress,” it adds.

The blanket does not use gels or refrigerants; rather, it employs three-layer evaporative cooling material.

“Propagation of more education about what heat does to a person would be helpful for safety managers and industrial hygiene specialists,” Booska suggests. “I think responsible parties continue to investigate new technologies and methods for providing safety and comfort for their workers.”

But worker health and safety extends beyond gear. To protect workers from adverse effects of heat, there must also be skilled people who carefully consider all aspects of a job and work conditions, Booska says.

“Corporate management must understand that a little investment now can save a lot,” he emphasizes.

Angela Stelmakowich is editor of OHS CANADA.

Sidebars
Full Effort

Guidelines exist for how long a worker should remain in certain temperatures, depending on the work load, notes information from the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ontario. Workload levels and some example activities include the following: rest — sitting; light — performing light hand or arm work; moderate — walking at a moderate pace or scrubbing while standing; heavy — digging or carrying, pushing or pulling heavy loads; and very heavy — very intense activity at a fast to maximum pace.

The CCOHS has developed the chart below, based on the Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, from the American Conference of Governmental Industrial Hygienists in Cincinnati.

ACGIH Screening Criteria for Heat Stress Exposure (values in Celsius)
Allocation of Work in a Work/Rest Cycle Acclimatized Action Limit
(Unacclimatized)
Light Moderate Heavy Very Heavy Light Moderate Heavy Very Heavy
75-100% 31.0 28.0 28.0 25.0
50-75% 31.0 29.0 27.5 28.5 26.0 24
25-50% 32.0 30.0 29 28.0 29.5 27.0 25.5 24.5
0-25% 32.5 31.5 30.5 30.0 30.0 29.0 28.0 27.0
Notes: Assumes eight-hour workdays in a five-day work week with conventional breaks; threshold limit values assume workers are adequately hydrated, not taking medication, wearing lightweight clothing and are in generally good health.


Sun No Fun

Too much heat can sometimes be too much to take. Although the internal temperature of a healthy body is usually about 37 degrees Celsius, a change exceeding 1 C threatens to surpass the ability of the body to cope, notes information from the Canadian Centre for Occupational Health and Safety in Hamilton, Ontario. To avoid responses such as dehydration, heat rash, heat strain, heat exhaustion and most serious of all, heat stroke, the combined effects of working, environmental sources and clothing must be considered.

The Atlanta-based Centers for Disease Control and Prevention notes that both employers and workers can do their parts to keep heat-related illnesses at bay:

– schedule hot jobs for the cooler part of the day;
– acclimatize workers by exposing them for progressively longer periods to hot work environments;
– monitor workers who are at risk of heat stress;
– wear light-coloured, loose-fitting, breathable clothing;
– take more breaks in extreme heat and humidity;
– drink water frequently (enough that one never becomes thirsty); and,
– avoid drinks that contain caffeine, alcohol and large amounts of sugar.


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