1.1 This standard practice covers the determination of the temperature rating of cold weather protective clothing ensembles. It involves measuring the insulation value of a clothing ensemble with a heated manikin in accordance with F 1291 and using a heat loss model to predict the lowest environmental temperature for comfort.

1.2 The predictive model used in this standard estimates the evaporative heat loss from a person wearing cold weather clothing as opposed to measuring the evaporative resistance on a sweating manikin. If a person is active and gets overheated in a cold environment, he/she can adjust the garments in order to dissipate excess heat.

1.3 The temperature ratings estimated by this standard practice are guidelines for thermal comfort that are designed to protect people from hypothermia when wearing cold weather protective garments. However, localized cooling, discomfort, and even frostbite could still occur at extremely low temperatures because clothing insulation is not evenly distributed over the body surface. In addition, some body parts (for example, ears, fingers, toes) have a high surface area relative to their mass, and consequently lose heat at a faster rate than other parts of the body.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.