Improving Comfort in Clothing

Guowen Song

• Publisher: Woodhead Publishing
• Year: 2011
• Print ISBN: 9781845695392
• eBook ISBN: 9780857090645
• Topic: Biological Sciences
• Subtopic: Human Anatomy & Physiology
• Index: Biological Sciences

Wear comfort has been listed as the most important property of clothing demanded by users and consumers according to recent studies. A fundamental understanding of human comfort and a knowledge of how to design textiles and garments to maximise comfort for the wearer is therefore essential in the clothing industry. Improving comfort in clothing reviews the latest developments in the manufacturing of comfortable apparel and discusses methods of improving it in various articles of clothing.The book begins by outlining the fundamentals of human comfort in clothing, from the human perception of comfort in apparel and factors which affect it such as the properties of fibres and fabrics, to laboratory testing, analysing and predicting of the comfort properties of textiles. Part two discusses methods of improving comfort in apparel, from controlling thermal comfort and managing moisture, to enhancing body movement comfort in various garments. Part three reviews methods of improving comfort whilst maintaining function in specific types of clothing such as protective garments, sports wear and cold weather clothingThe international team of contributors to Improving comfort in clothing has produced a unique overview of numerous aspects of clothing comfort, provides an excellent resource for researchers and designers in the clothing industry. It will also be beneficial for academics researching wear comfort. - Reviews the latest developments in the manufacturing of comfortable apparel and discusses methods of improving fit in various articles of clothing - An overview of how to design textiles and garments to maximise comfort begins with factors affecting comfort and properties of fibres and fabrics that contribute to human comfort - Improvements in thermal and tactile comfort and moisture management are explored featuring developments in textile surfaces

Part I

Fundamentals of comfort and assessment

1

Factors affecting comfort: human physiology and the role of clothing

A.K. Roy Choudhury, P.K. Majumdar and C. Datta, Government College of Engineering; Textile Technology, India

Abstract:

This chapter discusses the role of body components in maintaining body temperature and the principles of heat transfer to and away from the human body. Various aspects of thermal and skin sensational clothing comfort are explained. Special clothing for protection of the body from external hazards and their comfort properties are reviewed.

Key words

metabolic rate

human heat balance

mean radiation temperature

clothing comfort

clo value

protective clothing

The human environment must be aesthetically pleasing and must provide light, air and thermal comfort. The benefits of human-friendly atmosphere are:

• increased attention to work resulting in increased productivity, improved quality of products and services with fewer errors

• reduced absenteeism

• lesser number of accidents

• reduced health hazards.

When the comfort condition exists, the mind is alert and the body operates at maximum efficiency. It has been found that maximum productivity occurs under comfortable conditions and that industrial accidents increase at higher and lower temperatures. Postural discomfort due to a cold feeling results in just as many accidents as does mental dullness caused by a too warm environment.

1.1 Definition of comfort

Comfort is a fundamental and universal need of a human being. However, it is very complex and is very difficult to define. According to Fourt and Hollies (1970) comfort involves thermal and non-thermal components and is related to wear situations such as working, non-critical and critical conditions. The physiological responses of the human body to a given combination of clothing and environmental conditions are predictable when the system reaches steady state. According to Slater (1985), comfort is a pleasant state of physiological, psychological, neuro-physiological and physical harmony between a human being and the environment. He identified the importance of environment to comfort and defined the following three types:

1. physiological comfort is related to the human body’s ability to maintain life,

2. psychological comfort to the mind’s ability to keep it functioning satisfactorily without external help, and

3. physical comfort to the effect of the external environment on the body.

Although it is difficult to describe comfort positively, discomfort can be easily described in such terms as prickle, itch, hot and cold. According to Hatch (1993), comfort is ‘freedom from pain and from discomfort as a neutral state’. The discomfort arises from too hot, too cold, and odorous or stale atmosphere. Comfort conditions are those that do not cause unpleasant sensation of temperature, drafts (unwanted local cooling), humidity or other aspects of the environment. In ideally conditioned space, people should be unaware of noise, heat or air motion. Comfort depends on subjective perceptions of visual, thermal and tactile sensations, psychological processes, body–apparel interaction and external environmental effects (Li, 2001).

1.2 Human physiological aspect of comfort

1.2.1 Physiological interpretation

Physiological comfort is defined as the achievement of thermal equilibrium at normal body temperature with the minimum amount of bodily regulation. The body feels uncomfortable when it has to work too hard to maintain thermal equilibrium. Under the conditions of comfort, the production of heat is equal to the loss of heat without any action necessary by the heat control mechanisms. When the comfort condition exists, the mind is alert and the body operates at maximum efficiency. When the environmental temperature changes, the body tries to acclimatise by different temperature-regulating mechanisms–clothing also helps in acclimatisation.

1.2.2 Physiology and body temperature

Human beings are warm temperature animals and have a normal internal body temperature of 37 °C (98.6 °F) with tolerance of ± 0.5 °C under different climatic conditions. Any departure of body temperature from 37 °C causes changes in the rates of heat loss or heat production to bring the body temperature back to 37 °C. This crucial temperature level is called the set point of the various temperature control mechanisms that regulate the body.

Metabolic activity or oxidisation of foods results in the production of heat which can be controlled partially by controlling metabolic rate. However, metabolism during various activities of the body generates heat at varying rates. Hence, the body must reject heat at the proper rate to keep body temperature constant.

The mental state and physical operations done by the body are disturbed if the internal body temperature rises or falls beyond its normal range and serious physiological disorders or even death may occur if the temperature rises or falls to extreme levels. Often, the human body’s own immunological system also causes the rise of body temperature in order to kill infections or viruses.

The physiological reactions of body temperature will largely depend on the geographical location of the human being. The human being is accustomed to live in a certain atmosphere and can tolerate the temperature range existing in the surrounding area throughout the year. The reported physiological responses at various internal body temperatures are given in Table 1.1. When body temperature falls, the respiratory activity, particularly in muscle tissue, automatically increases and generates more heat. The extreme symptom of this form of body control is shivering (essentially rapid muscle contractions). Studies have shown that shivering can result in a five times increase in metabolism. ‘Goose bumps’ is really an attempt to raise the body hairs which doesn’t work too well since most humans are quite hairless.

Table 1.1

Physiological responses at different body temperatures

Body temperature	Physiological response
43.3 °C (110 °F)	Brain damage, fainting, nausea
37.8 °C (100 °F)	Sweating
37 °C (98.6 °F)	Normal
< 37 °C (98.6 °F)	Shivering and goose bumps
< 32.2 °C (90 °F)	Speechless
26.5 °C (80 °F)	Stiff and deformed body
< 26.5 °C (80 °F)	Irreversible body cooling

1.2.3 Role of body components in regulating body temperature

We have separate heat and cold sensors in our body. Heat sensors, located in the hypothalamus, send signals when skin temperature is higher than 37 °C. Cold sensors, located in the skin, send signals when skin temperature is below 37 °C. The higher the temperature difference, the more is the impulse. If impulses from both types of sensors are of the same magnitude, the body feels thermally neutral – if not, one feels cold or warm.

Role of anterior hypothalamus pre-optic area

The blood which circulates to all body tissues is warmed by the heat released within the body, thereby keeping various parts of the human body at the same temperature. The body temperature is a result of the balance between heat production and heat loss and is mostly regulated by a nervous feedback mechanism. An extremely sensitive portion of brain, called the ‘hypothalamus’, continuously records the temperature of blood and regulates body temperature, using the nervous system’s pathways, to a constant set point of around 37 °C (98.6 °F). It is stimulated when there is a minute change in temperature at any part of the body, say while drinking, eating or touching hot or cold materials.

The hypothalamus is the body’s thermostat and the large numbers of heat sensitive as well as cold sensitive neurons in the anterior hypothalamic pre-optic area of the hypothalamus are the temperature sensors for controlling body temperature. The hypothalamus triggers heat controlling mechanisms to increase or decrease heat loss ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Textiles
• Preface
• Part I: Fundamentals of comfort and assessment
• Part II: Improving comfort in apparel
• Part III: Improving comfort in particular types of clothing
• Index