Clothing Insulation Thermal Comfort

Metabolic rate clothing insulation and humidity.

Clothing insulation thermal comfort.

In cold climates this must be avoided at all costs as sweat wetted clothing exhibits a loss of thermal insulation see fig. Clothing is both a potential cause of thermal discomfort as well as a control for it as we adapt to the climate in which we work. A human body is a complicated thermodynamic system in which energy is constantly produced by metabolic activity and from which energy must be continuously dissipated into surroundings by dry thermal transport or latent heat loss accompanying water evaporation. Clothing insulation thermal comfort is very much dependent on the insulating effect of clothing on the wearer.

Clo 1 corresponds to the insulating value of clothing needed to maintain a person in comfort sitting at rest in a room at 21 70 with air movement of 0 1 m s and humidity less than 50 typically a person wearing a business suit. The amount of thermal insulation worn by a person has a substantial impact on thermal comfort because it influences the heat loss and consequently the thermal balance. There is no upper limit to air speed if occupant s total clothing 0 7 clo and metabolic rate 1 3 met. Besides dry bulb air temperature mrt and air velocity ansi ashrae standard 55 addresses three other factors affecting thermal comfort.

Wearing too much clothing or ppe may be a primary cause of heat stress even if the. Clothing insulation is the thermal insulation provided by clothing. The insulation effect of clothes can be measured in the unit icl clo where. Even if the main role of clothing is to protect from the cold protective clothing also exists to protect from heat such as for metallurgical workers or firemen.

Thermal comfort is primarily related to the efficiency of heat dissipation from clothes human body. As regards thermal comfort only the first case is considered. Layers of insulating clothing prevent heat loss and can either help keep a person warm or lead to overheating. Thermal comfort is very much dependent on the insulating effect of clothing on the wearer.

Cbe thermal comfort tool to calculate thermal comfort according to ashrae standard 55 2017 thermal comfort pmv ppd set adaptive comfort center for the built environment cbe uc berkeley predicted mean vote predicted percentage of dissatisfied standard equivalent temperature ole fanger richard de dear gail brager draft draught air movement metabolic activity clothing. The elevated air speed comfort zone method is to all spaces where the occupants have activity levels between 1 0 and 2 0 met and clothing insulation between 0 0 and 1 5 clo.