Baby, It’s Cold Outside!

It’s finally here…. Old man Winter has made his presence known here in Saskatchewan.  Along with cold temperatures, we have also had wind chills, making it feel even colder out there.  There are three main factors that modify our response to cold: air temperature, air movement (wind speed), and humidity.  For those who have to work in our sometimes harsh winter environment, these challenges must be counterbalanced to work safely.  A few things to keep in mind while reading this article are the following:

• Air Temperature is measured in degrees Celsius or Fahrenheit by an ordinary thermometer.

• Wind speed is measured in meters per second, kilometres per hour, or miles per hour. The following is a guide for estimating wind speed:

  • 8 km/h – light flag moves

  • 16 km/h – light flag fully extended

  • 24 km/h – raises a newspaper sheet

  • 32 km/h – causes blowing and drifting snow

• Humidity, or rather wetness, affects body temperature as water conducts heat away from the body 25x faster than dry air.

Whenever wind speed increases, a person feels colder regardless of the air temperature.  This combined effect of wind speed and cold air temperature is known as the ‘wind chill.’  Basically, it is the calculation of the feel of what the air temperature would be on exposed human flesh.  The following is a chart representing wind chill hazards and what to do as per Environment Canada:

Although there are no maximum exposure limits for cold working environments in Canada, there are guidelines that can be used to create safe work plans and protect the health and safety of workers who may be exposed to colder temperatures.  The Saskatchewan Department of Labour developed a “work warm-up schedule,” which has been adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) as Threshold Limit Values for cold stress.  This “work warm-up schedule” gives guidance for warm-up breaks that may be needed when working in colder temperatures.  As the wind speed increases and/or when the temperature decreases, additional breaks should be taken.  All non-emergency work should be stopped at temperatures of -43 degrees Celsius if there is no noticeable wind.  The following chart outlines the break times in more detail:

Note:

• This applies to moderate to heavy physical work in any 4-hour period

• Warm-up breaks should be in a warm environment for 10 minutes

• Norm breaks mean the normal break after 2 hours of work

• Guidelines apply to workers wearing dry clothing

• If there is limited physical activity, apply the schedule one step lower (more protective)

So what else can we do to prevent the adverse effects of cold?

• Equipment design – when working below the freezing point, machines and tools should be designed to operate without having to remove gloves or mittens. Also, a thermal insulating material should cover metal handles and bars.

• Emergency procedures – the provision of first aid and obtaining medical care should be outlined clearly, and at least one fully trained person should be assigned each shift with the responsibility of attending emergencies.

• Training – Supervisors and workers should be trained regarding working safely in cold environments and be familiar with the adverse effects of exposure to cold.

• Personal Protective Equipment – Protective clothing should be selected to suit the temperature, weather conditions and job design. Dress in layers with a wind-resistant outer layer.  Almost 50% of body heat is lost through the head, so wear a hat (a wool cap or liner under a hard hat can reduce excessive heat loss).  Felt-lined, rubber bottom, leather-topped boots with removable felt liners are best for heavy work in cold temperatures since the leather is porous, allowing the boots to breathe and let perspiration evaporate.  Always keep your socks dry, so carry extra pairs with you.

Remember to listen to the weather forecast and plan ahead!

References:

http://www.ccohs.ca/oshanswers/phys_agents/cold_working.html

https://www.getprepared.gc.ca/cnt/rsrcs/sfttps/tp201101-eng.aspx