Warming Trend

There is no other way to say it – Canadian winters are cold. Although this year is so far proving an exception to the rule, it is best not to assume “now” is forever when it comes to necessary protections against the elements.  

To help keep cold at bay, outdoor workers ranging from construction crews to marine personnel require head-to-toe protective clothing. Starting from the top and working on down, some of these options include winter hard hat liners, balaclavas, warming vests, waterproof gloves and boots.

In line

With the well-worn argument that a significant amount of heat loss occurs through an uncovered head – a common estimate is 45 per cent, although some argue it is simply that the head is more sensitive to temperature changes – the top is a logical place to start.

Typically designed to protect just the head and ears, there are, however, winter hard hat liners that cover the mouth, cheeks and neck through an extended nape and wraparound collar, notes information from Mine Safety Appliances Company (MSA) in Cranberry Township, Pennsylvania.

Same goes for face masks. Some of these “have an elastic body around the face, so you can move it up to your chin,” which, along with the neck, can get really cold, adds Claudio Dente, president of Dentec Safety Specialists Inc. in Newmarket, Ontario.

A balaclava, for its part, covers the entire head, including much of the face and neck. Choosing the specific type of balaclava will depend on the level of protection needed from the elements, work policies (some companies set a “no skin” rule to avoid frostbite and other cold-related injuries) and, as always, personal preference, says Adria Ensrud, a product specialist at Ergodyne in St. Paul, Minnesota.

Susan Pingree, a product line manager of eye/face protection and hard hat accessories at MSA, says that her company offers a water-repellant line of products that includes a neck gaiter for extra warmth on the neck – and the face when pulled up. Featuring green, soft-brushed twill on the inside, the winter liners have been chemically treated to resist burns from flames, with flame-retardant properties lasting for approximately 50 washings, Pingree reports.

Another product is made of special fibres that allow the layers of fabric to self-extinguish. These properties cannot be washed out, she adds.

And if there is the need to shine some light on a work situation, this can be aided by Ergodyne’s two-layer winter liners with LED lighted brim. The product has four LEDs spaced for illumination up to about 15 metres.

“Say good night to those bulky headlamps and cumbersome flashlights,” Tom Votel, president and CEO of Ergodyne, notes in a company statement released in December. The new liners are said to “offer the ultimate partnership between warmth and lighting for a safe and productive work site,” Votel contends.

Compatible combos

Keeping warm is important, but so too is safely completing the job at hand. “Think about a guy welding on a ship or a guy welding a building, doing steel structural work,” Dente offers. “They’ll be wearing a hard hat and a welding helmet and they are going to do something to keep themselves warm, especially if they are up high with the wind blowing.”

For any workers who may need to wear several forms of personal protective equipment (PPE) at once, compatibility and comfort are essential. While winter liners can weigh as little as about 60 grams, Dente cautions that some products are bulky, making comfort an ongoing challenge.

“You want [winter liners] to be soft around the skin, particularly around the chin and cheeks,” he says, citing fleece as a good choice of material.

While there is little concern around face shields worn by welders since liners fit underneath the helmet and the shield attaches to the brim, Dente suggests the compatibility of liners and hearing protection may not be quite as sound.

Consider a construction worker who wears earmuffs over a liner. “It is not going to give you the seal because the liner interferes with the seal to the ear cup,” Dente cautions. “It would be recommended that you go to an earplug, which would fit in underneath and provide the hearing protection.”

To help ensure a proper fit with earmuffs, Pingree says MSA has four winter liners which feature quilted flaps that open at the ears. “Without interference from the fabric, the muff has a secure seal, and does not negate the expected hearing protection levels. When not in use, the flaps close to help ensure warmth.”

The company also offers a two-piece liner, the bottom portion of which can be removed to accommodate earmuffs.

Pingree says that MSA has made some changes to its products after taking a cue from workers in the field. “In field observation, not one person used the back hook or loop closure that generally goes over the suspension, intended to hold the liner securely,” she reports. “When asked why they didn’t use it, most cited that they didn’t need it to keep the product secure, and the fastener actually interfered with the ratchet or other closure on the helmet suspension.”

For those wanting to beef up liner protection, Dente says some that products can be fitted with pockets to carry warmers. The warmers – which can be inserted into gloves, footwear and between layers of clothing – typically provide heat for six to 18 hours.

There are also cold weather survival heat packs, which can be carried in a vehicle and slipped inside a coat if a worker becomes stranded and is waiting for help to arrive. Dentec Safety has a pack that comes in a resealable container and cold weather kits with warmers that provide dozens of hours of welcome heat.

Over, under

Stranded or not, layering can help keep the cold out, although if done incorrectly, it can have the opposite effect, advises Chris Ransome, president of Ranpro Inc. in Simcoe, Ontario. “Most often, people focus on protecting themselves against cold entering externally and forget to consider what is happening at the core where body heat is generated,” Ransome says.

“Wrapping yourself in thick protective layers to keep the cold out becomes a problem once the body begins to work and generate heat,” he explains. “This heat leads to perspiration which, if allowed to dry on the skin, cools the skin and subsequently lowers your internal body heat.”

Using an appropriate base layer is the foundation from which to safely build protection. Thermal base layers that wick moisture away from the skin not only prevent the chill from setting in, they allow for enhanced mobility by eliminating the need for many bulky layers, Ransome says.

A moisture-absorbing base layer coupled with a moisture-wicking mid-layer keep internal temperatures steady and lessen the need to doff outer layers during strenuous work and re-dress once work becomes less taxing, he adds.

Ergodyne’s Adria Ensrud notes that the average worker sweats eight litres in an eight-hour workday. “The key is to manage the perspiration effectively, by wicking it away from your skin where it can evaporate,” Ensrud says.

With effective heat transfer in mind, Ranpro offers three heavy-duty, mid-layer garments specifically designed for marine workers who face a mix of wet and cold – a basic jacket, a hooded jacket and pants.

In addition to providing a comfortable, protective layer, the clothing uses foam technology to help regulate the wearer’s core temperature. When a wearer is active and working, the foam expands to release warm air and allow cool air to enter. When the worker is at rest, the foam constricts to retain body heat.

Ransome says the suit maintains thermal-regulating properties in water, employing the four-millimetre-thick foam shell as insulation. It also serves as a “float assist,” providing 83 per cent of the buoyancy of a personal flotation device.

At Ergodyne, the company’s CORE Performance Work Wear features a thin,
moisture-wicking tight layer next to the skin that transports moisture to mid- and outer layers. Loose-fitting mid-layers work to trap warm air, Ensrud explains, while the outer layer provides additional insulation and protection from the harshest elements.

All suit seams are flat-stitched to ensure they will not rub or irritate the skin, and knees and elbows are articulated to provide freedom of movement, he says.

If flexibility and warmth are desired, Ergodyne has a mid-layer warming vest that uses argon gas for insulation. With a density of about 1.78 grams per litre (g/L) compared with the density of air at 1.29 g/L, Ensrud contends that it is the lightest insulation agent on the market. “It comes with a dial, so a worker can let out some of the gas to custom and vary their level of warmth.”

All wet

For jobs like fishing and outdoor construction that are performed not only in the cold, but in wet conditions, a waterproof glove or glove with a waterproof membrane can help complement other PPE, says Joe Geng, vice-president of Superior Glove Works Ltd. in Acton, Ontario.

Geng’s company has one glove that features a layer of polyurethane between the outer glove and inner lining, a waterproof membrane that extends from the fingertips to the top edge of the cuff, elasticized cotton backs and split-cowhide palms, fingertips and index finger, notes a product information sheet.

Of course, when minimal dexterity and maximum warmth are required, mitts fit the bill. “Mitts are warmer than gloves because of less surface area and improved circulation,” Geng says, which helps prevent isolated cold spots from forming.

For glove liners, he recommends using either those made from wool or Thermolite liners over cotton or poly liners. Wool continues to insulate even when wet; Thermolite helps to wick moisture away from the skin.

A chart from Superior Gloves compares lining materials commonly used in gloves: While cotton flannel registers mid-range for both warmth and bulkiness, the counts for foam fleece liners is somewhat higher for both categories. Warmth measures for boa acrylic (a synthetic lining) and 3M Thinsulate are higher still.

Geng says using a liner inside of a non-winter glove is a good option, provided the fit is okay. “You want to make sure there is plenty of room for the liner as this will improve the insulation – too tight and the insulation factor will suffer.”

Geng reports there is a trend toward two-layer knitted glove construction, which seeks to balance needs around warmth and touch sensitivity. For example, nylon gloves with a polyvinyl chloride-coated palm feature micropores – tiny air bubbles that stay supple even in cold temperatures – to provide optimal flexibility, notes a product sheet from Superior Gloves.

Well-suited for commercial fishing, agriculture, construction, utilities and cold storage, the quick-drying glove also provides a good grip in wet or dry conditions.

But tiny air bubbles are not just for waterproof gloves. Ransome says Ranpro’s line includes boots that can keep feet warm at as low as -50 degrees Celsius.

Ransome points out that cold can be transferred from standard steel plates and toe caps in safety shoes or boots into the foot. One of his company’s offering is designed to prevent this cold transfer by employing the same tiny air pockets that regulate the temperature of the rest of the foot.

“The best way to reduce or eliminate the risks associated with cold stress is simply to be aware of the risks, be prepared and be ready to react,” advises Ensrud. “Plan for work in cold weather, wear appropriate clothing and be aware of how your body is reacting.”

Whether a company’s strategy is using thousands of insulating bubbles, layering or a combination of products and techniques, it is clear that workers should look at the big picture to keep cold-related injuries at bay. By focusing on the head, feet and everything in between, workers can keep warm – and safe – as Canada’s coldest season gets settled for its months-long stay.   Follow us on Twitter @OHSCanada  

Jason Contant is editor of canadian occupational health & safety news.

Sidebar:

Core Crunch

Subject to intense cold without the benefit of adequate clothing, the body is unable to compensate for heat loss and its core temperature will start to fall, notes information from the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ontario.

 The sensation of cold followed by pain in exposed parts of the body is an early sign of mild hypothermia. If core temperature drops from the norm of about 37 degrees Celsius to 32 to 34 C, the COOHS reports that the body’s response may include violent shivering, difficulty speaking and sluggish muscle movements, as well as the person possibly showing signs of depression.

 Should core temperature fall even further – say from 28 to 30C – muscle rigidity, semi-consciousness, stupor, loss of awareness of others, decreased pulse and respiration rate and possible heart fibrillation may occur. Heart activity stops at approximately 20 C, followed by brain function at about 17 C, the information adds.