Following the popularity of our hot weather survival guides for construction and events, we put together guidelines for staying safe in cold weather. Construction employees who work outdoors know that enduring cold weather can be difficult and even dangerous.
There are three specific cold weather factors that affect outdoor construction workers:
Air temperature is measured by your run-of-the-mill thermometer, and is represented in degrees Celsius or Fahrenheit.
Wind speed or air movement is measured by an anemometer. Air movement is usually measured in metres per second, while wind speed is typically measured in kilometres or miles per hour. When wind speed is combined with a cold air temperature, it creates a “wind chill” and causes you to feel colder.
Believe it or not, humidity levels can impact how cold weather affects you. Water conducts heat away from the body 25 times faster than dry air, creating a more dangerous environment for outdoor workers.
We know that the human body is affected by these three factors in cold weather, but what exactly are the specific health effects?
The biggest concerns for anyone working on a job site in winter are generally hypothermia and frostbite. According to Environment Canada, unless you have adequate protection, you are at risk of hypothermia and frostbite when the air temperature drops down below -10°C.
At -28°C, the risk of frostbite is considered to be high, and the risk of hypothermia increases. At this temperature, exposed skin can freeze in 10 to 30 minutes. Once the temperature reaches -40°C, the risk of frostbite and hypothermia becomes very high. It takes only 5 to 10 minutes for exposed skin to freeze.
If temperatures drop below -48°C, the risk of frostbite and hypothermia is so severe that any non-essential outdoor activities should be avoided completely.
Aside from the direct impact of cold on the human body, there is another effect that is easily overlooked – but just as dangerous. Extreme cold weather may cause outdoor construction workers to become so distracted by their discomfort, that they can become more likely to have an accident.
If you want to stay safe while working outdoors, you must counterbalance the effects of the environment. Use the following measures to help protect yourself against the dangers of cold weather while on a construction site:
According to the Canadian Centre for Occupational Health and Safety, protective clothing is needed for work at or below 4°C. Of course, you should do your best to select clothing that is suitable for the temperature, weather conditions, and type of activity or job.
For instance, if you anticipate working in wet conditions such as rain or snow, make sure the outermost layer of clothing is water repellent. Cotton is generally not the best option in cold weather, as it gets damp quickly, causing it to lose its insulating properties. Instead, opt for wool or synthetic materials. They can still retain heat when damp, making them the better choice for cold, wet weather.
It’s important to wear clothing that is appropriate for the type of work you are doing. If you wear improper clothing for the pace of work, you might experience excessive sweating. This is dangerous because the clothing against your body will become wet and its insulation value will be dramatically reduced. Recall that water conducts heat away from the body 25 times faster than dry air. The reduced insulation value of wet clothing increases your risk of cold-related injuries.
To prevent this kind of scenario, your innermost layer should provide insulation while also keeping your skin dry. Look for clothing with moisture-wicking properties, such as thermal underwear made from polyester or polypropylene.
In general, multiple layers offer better protection than a single thick article of clothing, since air pockets between the layers provide greater insulation than the clothing itself. Layering your garments also allows you the flexibility to add or remove clothing as needed to adapt to changing temperatures or the pace of work.
Don’t forget to protect your ears! Ideally, you should wear a warm hat that covers your ears. However, construction workers are generally limited by the requirement that they wear a hard hat on site. Although some knitted caps may fit under a hard hat, your best bet may be to source a liner specifically designed for hard hats. A proper liner can help reduce excessive heat loss and keep your head warm.
Though it can be hard to perform certain tasks while wearing gloves, if you can compromise some of your manual dexterity then gloves are recommended in temperatures below 4°C. Once temperatures dip below -17°C, mittens are your best bet.
Proper footwear is also a must. Steel-toed boots with a rubber bottom and a leather top are best-suited for working on a construction site in the cold. Leather is porous, allowing the boots to “breathe” and sweat to evaporate, keeping your feet dry. Of course, fully waterproof boots are best for a very wet environment – even if they do prevent sweat from evaporating. Regardless of the style of boot, we recommend using removable felt liners and insoles to add some extra warmth on especially cold days.
If you can, plan to have extra socks on hand so that you can change them throughout the day. In the winter, your feet may sweat or become wet due to seeping snow or slush. Having dry socks available is key to keeping your feet warm.
Finally, don’t overlook your eye wear. Your job may require you to wear protective eye wear, and there are additional factors to consider in the winter – like UV protection, glare from the snow, and blowing snow or ice crystals.
Your physical activity (metabolic rate) produces body heat, which is measured in kilocalories (kcal) per hour. It takes just one kilocalorie of heat to raise the temperature of one kilogram of water by 1°C. Physical activity is a good way to raise or maintain your internal temperature in cold weather. In fact, you should avoid sitting or standing still for prolonged periods of time when working in a cold climate.
That being said, if your job is physically strenuous then it’s important to try and control how much you sweat. You want to avoid ending up with damp clothing, which will make you feel colder. This is when it becomes important to dress in layers that can be removed as your body heat rises.
Extreme heat requires planned rest periods in cool, shaded areas to give the body a break. A proper rest schedule is just as important when the temperature drops. Thankfully, The Saskatchewan Occupational Health and Safety Division has developed a “work warm-up schedule” to help you plan for controlled exposure to cold weather conditions.
Warm-up breaks should begin when the temperature reaches -26oC (-15oF) with winds of 16km/h (10mph) or greater. All non-emergency work should stop by the time the temperature reaches -43oC (-45oF), even if there is no noticeable wind. The complete work warm-up table can be found here.
Warm-up breaks should consist of at least 10 minutes spent in a warm environment, like a heated building or a running truck.
Direct contact with ice, frozen metal and very cold liquids can cause ice burn or frostbite to exposed skin. If you are working outdoors in freezing conditions, it’s important to adapt your equipment accordingly. You should prevent any contact between bare skin and cold surfaces below -7°C. Also aim to avoid skin contact when handling evaporative liquids such as gasoline and cleaning fluids below 4°C.
Ideally, look for machines and equipment that can be operated without having to remove your mittens or gloves. If that’s not possible, cover any metal components that will be touched with your bare hands – such as handles and bars – with thermal insulating material.
Proper nutrition might not be the first thing you think of when it comes to working in cold environments. As a matter of fact, nutritionally balanced meals and adequate liquid intake are crucial in cold weather to help maintain body heat and prevent dehydration. That’s because your body requires more energy to stay warm in the cold. Cold weather work can also require more physical effort due to bulky clothing, heavy winter boots, and deep snow.
If your job requires you to work in a cold environment, make sure you are eating properly and frequently. Drink fluids often to stay hydrated, especially if the work you are doing is labour intensive. Hot beverages and soup will help hydrate you while also warming you up. However, you should try and limit the amount of coffee you drink. Caffeinated beverages increase your urine production, contributing to dehydration. They also cause you to lose body heat, since they increase the blood flow at the surface of the skin.
Education is arguably the first step in preventing cold injuries – or any workplace injuries, really. If your employees are required to work in cold environments, make sure they are informed about the adverse effects of prolonged exposure to cold. Teach them about the proper clothing, safe work practices, and work-rest schedules recommended for working in the cold.
Most importantly, ensure everyone is aware of the emergency procedures in case of a cold injury. Clearly outline emergency procedures for providing first aid and obtaining medical care, and post them in employee handbooks and break rooms.
Consider implementing a buddy system for very cold days. Have your employees be on the lookout for the symptoms of hypothermia in their peers, which include:
First aid should be administered immediately if hypothermia is detected. Depending on the severity of the hypothermia, medical attention may be required. At a minimum, you should:
For a complete list of symptoms and treatments of hypothermia, please see the Mayo Clinic website.
The measures we’ve outlined here are important first steps, but there is a wealth of information available to further your education when it comes to working in the cold. The Canadian Centre for Occupational Health and Safety is a great resource for anybody working outdoors this winter.
Working outside in very cold conditions can be dangerous, and is unfortunately unavoidable for many Canadians. By taking the appropriate measures, you can protect yourself from the adverse effects of cold weather work, and stay safe and warm this winter season.
We’re here to answer any questions you may have.