clo

Relative measure of the ability of insulation to provide warmth. One clo is defined as the amount of clothing required by a resting (sedentary) person to be indefinitely comfortable at ambient conditions where temperature is 21°C (70°F), relative humidity is less than 50 percent, and wind velocity is 250 centimeters per second or about 0.9 kilometers per hour (about 20 feet per minute or just over half a mile per hour). Lowest clo value (0) is that of a nude person, highest practical clo value (4) is that of Eskimo clothing (fur pants, coat, hood, gloves, etc.). Winter clothing (weighing about 6.6 pounds) has an average clo value of 1, and summer clothing (weighing about 3.90 pounds) of 0.6. One clo equals 1.55 tog. See also R-value.