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 insulation thermal comfort.

Layers of insulating clothing prevent heat loss and can either help keep a person warm or lead to overheating. 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. Wearing too much clothing or ppe may be a primary cause of heat stress even if the. 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.

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. There is no upper limit to air speed if occupant s total clothing 0 7 clo and metabolic rate 1 3 met. You may add layers of clothing if you feel cold or remove layers of clothing if you feel warm. Metabolic rate clothing insulation and humidity.

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. 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. When evaluating the level of thermal comfort in a space consider all six factors especially if you have occupants who report feeling cold or warm. As regards thermal comfort only the first case is considered.

Besides dry bulb air temperature mrt and air velocity ansi ashrae standard 55 addresses three other factors affecting thermal comfort. Thermal comfort is very much dependent on the insulating effect of clothing on the wearer. Clothing insulation is the thermal insulation provided by clothing. 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.

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. The insulation effect of clothes can be measured in the unit icl clo where.