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What I wear today?


How many times to get dressed and go out, we realized that we did not warm enough or we have exceeded the time to dress?

In this article, we explain that we can be sure that the clothes chosen for a particular day will be adequate.

It is evident that on a normal day of our lives, "this error" the dress is acceptable, but imagine what would happen in an extremely cold environment, or in an environment neither cold nor hot but where I'll be making a strong activity. Risks could suffer hypothermia or dehydrate in the other case by excessive sweating. In no way can afford tools exist for it.

There are situations where you'll be sure to maintain thermal comfort can be vital.

But what is thermal comfort?

Man has always wanted to create an environment where FOUND thermal comfort and there are several definitions found in this state, since the thermal comfort is that condition of mind which expresses satisfaction with the thermal environment, other than those defined as conditions the men, women and teams work effectively.

Thus, successive definitions have something in common, and that is if we are not comfortable in our environment, our performance will inevitably decline.

The definition of comfort that we use in this study is defined at physiological or heat balance, expressed as:

M-W ± K ± R ± C ± RES - E = 0

This is the equation that will allow us to decide whether a dress will be appropriate to the activity and the environment they'll be exposed.

Let us briefly discuss the meaning of each term in Eq.

The main source of heat for the body's metabolic heat production (M). The units used are usually the watts. It is the main body thermogenesis process.

Mechanical work symbolized by W represents the energy carried by the body in all its movements and life cycles (minus).

Heat can also be absorbed into the body environment by radiation processes (R), contact (K) and convection (C) if the ambient temperature exceeds body temperature. Treat small heat sources in comparison to M, but must be considered for greater accuracy of the calculations. In case the ambient temperature is lower than the body, the heat radiation or convection contact would be negative, since the body heat lost to the environment.

There are also heat gains and losses through respiration, either because they breathe air at high temperatures or because it is at low temperatures (RES).

The final process of thermolysis or heat loss is evaporation (E), and is usually the most important since the latent heat of evaporation of sweat is high, and can consume approximately 680 W per hour with the evaporation of one liter of sweat. On this, there is much to say, I will discuss in future articles.

It is now that we can answer the question, What is thermal comfort?

That situation where heat gains are equal to the heat loss.

Whenever man can, try to get environmental conditions where your body must make a minimum effort to be in a position of comfort. That is, controlling:
• Air temperature
• mean radiant temperature
• partial pressure of water vapor
• Air Velocity
• The metabolic rate (our activity)
• The characteristics of the clothing

But what if we can not control the first 4 parameters?

The last two are now more vital.

The clothing system greatly influences the thermal comfort.

Both more clothes to help us get the comfort equation is satisfied, more easily acquire the thermal comfort, one in which thermogenesis, equals the thermolysis.

Well, there are three studies, in my opinion very interesting basis for the publication of three international standards.

They are the basis of the prediction for the determination of whether a dress is appropriate for the environment in which we are exposed.
• For the balance in cold conditions. IREQ isolation index according to ISO / TR 11079 (for ambient temperatures below 10 ° C)
• To balance under neutral conditions. PMV-PPD index according to ISO 7730 (for environments with temperatures between 10 and 30 º C)
• For the balance in hot conditions. Index required sweat rate according to ISO 7933 (for environments with temperatures above 30 º C)

Each of these rules is always used for the same purpose; find thermal comfort.

I can only comment one last little thing but not least:

Acclimatization, the needs of a person acclimated to an environment may be quite different from those of a person not acclimated. Let's not forget that this factor should be taken into account for any personalized study.

If you need more information on how to use these tools, just send us your query.

A comfortable greeting.