Appendix A: The Equivalent Chill Temperature Chart
The equivalent chill temperature (ECT) chart relates the actual dry bulb temperature and the wind
velocity. The ECT, often called the wind chill temperature, is a crucial factor to evaluate when
working outside. It should be used when estimating the combined cooling effect of wind and low air
temperature on exposed skin or when determining clothing insulation requirements.
Estimated Actual temperature reading (°C)
10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50
(in km/h) Equivalent chill temperature (°C)
0 (Calm) 10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50
8 9 3 -2 -7 -12 -18 -23 -28 -33 -38 -44 -49 -54
16 4 -2 -7 -14 -20 -27 -33 -38 -45 -50 -57 -63 -69
24 2 -5 -11 -18 -25 -32 -38 -45 -52 -58 -65 -72 -78
32 0 -7 -14 -21 -28 -35 -42 -50 -56 -64 -71 -78 -84
40 -1 -8 -16 -24 -31 -38 -46 -53 -60 -67 -76 -82 -90
48 -2 -10 -17 -25 -33 -40 -48 -55 -63 -70 -78 -86 -94
56 -3 -11 -18 -26 -34 -42 -50 -58 -65 -73 -81 -89 -96
64 -3 -11 -19 -27 -35 -43 -51 -59 -66 -74 -82 -90 -98
(Wind speeds LOW HAZARD INCREASING HIGH HAZARD
greater than Risk of exposed, dry HAZARD Flesh may freeze within 30
64 km/h have skin being affected Danger from seconds.
little in less than one freezing of
additional hour. Awareness of exposed flesh
effect.) hazard low. within one
(Source: British Columbia’s Cold Stress Regulation, Part 7)
The table was originally developed by the U.S. Army Research Institute of Environmental Medicine, Natick, MA, and is adapted from the 1995-1996
Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, published by the ACGIH. The ACGIH
publication provides the equivalent table with temperature in degrees Fahrenheit and wind speed in mph.
Equivalent chill temperatures for actual temperatures and wind speeds not listed in this chart may be calculated by interpolation. For example, at a wind
speed of 16 km/h, an actual temperature reading of -23°C (3/5 of the difference between -20°C and -25°C) produces an equivalent chill temperature of -
36°C (3/5 of the difference between -33°C and -38°C).
Appendix B: Work-Warming Schedule
If work is performed continuously in low temperatures and high wind conditions, the Threshold Limit Values (TLVs) of Work/Warm-up
Schedule should be consulted to determine the maximum length of a work period and number of work breaks.
Air Temperature- No Noticeable 8km/hr Wind 16km/hr Wind 24km/hr Wind 32km/hr Wind
Sunny Sky Wind
Max. No. Max. No. Max. No. Max. No. Max. No.
C (approx.) Work of Work of Work of Work of Work of
Period Breaks Period Breaks Period Breaks Period Breaks Period Breaks
-26 to -28 (Norm. Breaks) 1 (Norm. Breaks) 1 75 min 2 55 min 3 40 min 4
-29 to -31 (Norm. Breaks) 1 75 min 2 55 min 3 40 min 4 30 min 5
-32 to -34 75 min 2 55 min 3 40 min 4 30 min 5
-35 to -37 55 min 3 40 min 4 30 min 5
-38 to -39 40 min 4 30 min 5 Non – emergency Non – emergency
-40 to -42 30 min 5 Non – emergency work should cease work should cease
Non – emergency
-43 & below Non – emergency work should cease work should cease
work should cease
(Source: 1999 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, published by the ACGIH)
This schedule was developed by the Occupational Health and Safety Division of the Saskatchewan Department of Labour and adopted by the American
Conference of Governmental Industrial Hygienist (ACGIH).
1. Schedule applies to any 4-hour period with moderate to heavy work activity, with warm-up periods of 10 minutes in a warm location and with an extended
break (e.g. lunch) at the end of the 4-hour work period in a warm location. For Light-to-Moderate Work (limited physical movement); apply the schedule
one stem lower. For example, at –35oC (-30oF) with no noticeable wind, a worker at a job with little physical movement should have a maximum work
period of 40 minutes with 4 breaks in a 4-hour period.
2. The following is suggested as a guide for estimating wind velocity if accurate information is not available:
8 km/hr: light flag moves; 16 km/hr: light flag fully extended; 24 km/hr: raises newspaper sheet; 32 km/hr: blowing and drifting snow
3. TLVs apply only for workers in dry clothing.
Guidelines for the Prevention of Cold-Stress Related Injuries Page 6 of 7
COLD STRESS HAZARDS INFORMATION SHEET
Cause Signs and Symptoms Treatment Prevention
Frostbite Frostbite is the formation of ice Early warning symptoms include a cool Move to a warm place and apply warmth Wear woollen socks to protect your
crystals in exposed body parts. It sensation in the affected area with the to the affected parts. ankles and feet. Carry an extra pair
occurs when extremities such as skin turning a lighter colour. of socks when moisture or sweating
the hands, feet, ears, and nose are Use a blanket and/or body heat to warm is likely and change when needed.
exposed to cold for an extended Pain in the extremities is usually the first the person.
period of time. sign of danger. The affected part will also Keep snow and water out of your
become pale and numb. DO NOT use alcohol as a warming agent. footwear. Use silicone treatment for
Contact with gasoline, and some leather boots.
cleaning fluids left outdoors can Severe frostbite is characterized by hard DO NOT submerse the person in hot
cause instant frostbite because skin that has turned blotchy or blue. water or a warm shower. This may result Wear a face mask while working in
these liquids do not freeze when the in “re-warming shock”. cold wind.
temperature falls below the freezing
point. DO NOT rub the frostbitten area. Wear mittens instead of gloves
Hypothermia is the over cooling of Early warning signs of hypothermia SEEK MEDICAL ATTENTION. Move to a warm area periodically
Hypothermia the body due to excessive loss of include excessive shivering, blue lips and throughout the day to ensure a
body heat. Although highly unlikely fingertips, slurred speech and poor Move the person to a warm shelter as normal core body temperature is
under winter work conditions for City coordination. soon as you notice the warning signs of maintained.
of Toronto employees, hypothermia hypothermia.
is a potentially fatal condition, which More severe hypothermia impairs mental Wear multiple layers of light, loose-
requires immediate medical functioning, resulting in confusion, Use a blanket and/or body heat to warm fitting clothes.
attention. disorientation and poor decision making. the person.
At this stage the individual may have lost Wear cotton or polypropylene long
all desire or ability to seek protection from If conscious, give warm, non-alcoholic underwear.
the cold, resulting in additional rapid loss drinks in small quantities.
of body heat. Wear waterproof/ water-resistant
DO NOT use alcohol as a warming agent. outerwear.
DO NOT submerse the person in hot
water or a warm shower. This may result
in “re-warming shock”.
Guidelines for the Prevention of Cold-Stress Related Injuries Page 7 of 7