Comfort is a key factor to be considered in clothing design.

1. Submitted to
Prof. Md. Abul Kashem
Head
Department of Appaarel engineering
Bangladesh University of Textiles
Submitted by
Jahirul Alam Chowdhury
Md. Rasel Hossen
M.Sc. In Textile Engineering
Department of Apparel engineering
Bangladesh University of Textiles

2. Human comfort is complex and subjective, and is influenced psychologically and
physiologically by clothing and surrounding environmental conditions. The basic
requirements of clothing to provide protection against hazards and give a
aesthetic appearance simultaneously maintaining an acceptable level of human
comfort.
Comfort is the basic consideration designing a new garments and one of the
challenge in this arena is thermal comfort.
In this presentation we will discuss about thermal comfort, needs of thermal
comfort, basic factors, mechanism of thermal comfort and different approach
to thermal comfort.

3. Comfort (or being comfortable) is a sense of physical or psychological ease, often
characterized as a lack of hardship.
comfort is a pleasant state of physiological, psychological, neuro-physiological and
physical harmony between a human being and the environment.
-Slater (1985)
Clothing comfort is a state of satisfaction indicating physiological, psychological and
physical balance among the person.

4. There are two main factors that determine comfort clothing:
 External Factors
 Internal Factors
External factors like the environmental temperature, moisture, wind, cultural and social
influences which affect the comfort in clothing.
Internal factors such as an individuals metabolic rate, level of activities, economic and health
position, social experiences, and psychological situations.
these two types of factors are instrumental in establishing the level of comfort in clothing.

5. Thermal: heat and mass transfer
Sensorial: tactile, touching, hand-feel
Movement: movement of body parts
Social: status, forces dress
Psychological: aesthetic sense, design is different for kids and old people, colorful dress of
ladies.
Functional: helpful for any function, firefighter dress.

6. The condition of mind which express satisfaction with the thermal environment.
-ISO 7730
Thermal comfort is the primary needs of clothing, as an important function of clothing is
to provide aids in maintaining the thermal balance of the human body and ensure that
the heat loss, skin temperature, air movement and humidity at the body surface produce
a sensation of comfort.
There are three main approaches in the development of clothing for improved comfort,
i.e. the appropriate use of textile materials, garment design and attachment of special
wearable devices into the garment system.

7. Occupant Satisfaction and Productivity
75% of all occupant complaints within buildings are thermal comfort related
The thermal environment has been shown to have up to a 10% effect on worker productivity
Energy consumption
Over $80 billion per year is spent to heat and cool buildings

8. The six factors affecting thermal comfort are both environmental and personal.
These factors may be independent of each other, but together contribute to an
employee’s thermal comfort.
 Environmental factors:
Air temperature
Radiant temperature
Air velocity
Humidity
 Personal factors:
Clothing Insulation
Metabolic heat

9. Air Temperature:
This is the temperature of the air surrounding the body. It is usually given in degrees Celsius.
Radiant temperature:
Thermal radiation is the heat that radiates from a warm object. Radiant heat may be present if
there are heat sources in an environment.
Air velocity:
This describes the speed of air moving across the employee and may help cool them if the air is
cooler than the environment.
Relative Humidity:
Relative humidity is the ratio between the actual amount of water vapor in the air and the
maximum amount of water vapor that the air can hold at that air temperature. Relative humidity
between 40% and 70% does not have a major impact on thermal comfort.

10. Clothing insulation:
Thermal comfort is very much dependent on the insulating effect of clothing on the
wearer. 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. You may add layers of clothing if you
feel cold, or remove layers of clothing if you feel warm.
Work rate/metabolic heat:
The more physical work we do, the more heat we produce. The more heat we produce,
the more heat needs to be lost so we don’t overheat. The impact of metabolic rate on
thermal comfort is critical.

11. The body uses thermo-regulatory mechanisms to compensate the gain or loss of heat to
keep body temperature in equilibrium. This system is known as the hypothalamic
thermostat, which "tells" the body to increase or decrease the temperature, in accordance
with thermal needs.
Thermal comfort is satisfied with the thermal environment and does not need to use
thermo-regulator mechanism. When temperature is more or less than this body feels
discomfort, as a result human body needs some external agency to maintain this
temperature and clothing is one of the most common devices to provide comfort in this
regard.

12. Heat Balance
The human body tries to maintain a constant core temperature of about 370C. The
efficiency of the human organism is such that of the energy taken in as food only
15 - 30% is converted into useful work with the remaining 70 - 85% of the energy
being wasted as heat.
The heat balance is mathematically expressed as below :
Q = M ± R ± C∞v ± C∞d – E
Where,
Q = Heat gain or loss
C∞v = Convective gain or loss
C∞d = Conductive gain or loss
E = Evaporative loss
M = Metabolism
R = Radiant gain or loss
Heat lose:
There are five mechanisms like conduction, convection, radiation, evaporation and
respiration that allow the body to lose heat to the environment in order to
maintain its thermal balance.

13. There are different approaches in the development of functional clothing for
improvement of thermal comfort.
The appropriate use of textile materials
Creativity in design and
Attachment of special wearable devices into the garment system.

14. Clothing thermal comfort relates to many different factors of textile materials,
such as:
fiber types,
yarn type,
yarn smoothness,
fabric structure,
fabric thickness and
special material.

15. Appropriate use of Textile Fibers:
 The moisture absorbency of the fibre is directly related to the moisture regain of the fibre
or fabric
 In the normal situation, fibre with higher moisture regain could absorb more moisture and
heat from the body.
 Natural fibres like wool and cotton have been shown to have higher ability to absorb large
amounts of moisture due to their hygroscopic properties.
Appropriate use of Fabric Construction:
Fabric structure and its thickness influence the heat and moisture transfer and hence
thermal comfort. This is because fabric structure and thickness affect the air and moisture
permeability, which play a significant role in heat and moisture transfer

16. Use of single or multiple fabric layer(s) in the garment construction:
the number of fabric layers also contributes to the thermal insulation and moisture vapor
resistance of the clothing system. In general, more layers create additional layers of still air
resulting in higher thermal insulation and moisture vapor resistance compared to a single layer
of fabrics.
Special undergarment construction to improve ventilation:
designers have developed special constructions between fabric layers with a series of
parallelraised ribs or cords to form the air channels. heat and moisture transferred
from the undergarment could be released from this air gap.

17. Waterproof breathable fabrics:
It is consist of an outer layer called the “face fabric”, usually made of nylon or polyester,
and a laminated membrane or coating, usually made of ePTFE (expanded
Polytetrafluoroethylene, also known as Teflon) or PU (Polyurethane) which resist liquid water
passing through, but allow water vapour to pass through.
Moisture management fabric:
the ability of a garment to transport moisture away from the skin to the garment's
outer surface. This action prevents perspiration from remaining next to the skin.

18. Phase change material:
Substances that undergo the process of phase change are also known as phase change
materials (PCMs). These materials store, release or absorb heat as they oscillate between
solid and liquid form, giving off heat as they change to a solid state and absorbing it as they
return to a liquid state.
Some PCMs change phases within a temperature range that is just above and just below
human skin temperature. This property now is being used in fabric and foam to store body
heat and then release it when needed.

19. Garment fit is considered as one of the elements that influence thermal insulation
and evaporative resistance and there has been a clear relationship of garment fit and
clothing insulation.
tight-fit clothing had 6–31% lower insulation than loose-fit ones. the difference was highest
during sitting and decreased in windy conditions.
There are some established way of garments design basic for increasing thermal comfort.
Ventilated clothing.
ventilated garments having protective shield layers.
Garment ventilation apertures with cover flap.
Garment with structural vent.
garment with comprised of cords.

20. Ventilated clothing:
Vents are designed into the garments so the air space between the skin and the inner
fabric layer changes over time, depending on the level of activity and movement. This design
developed in away that body heat and moisture vapor can be released through the pores.
ventilated garments having protective shield layers:
This design developed to allow ambient air to pass into the body skin surface from the mesh
panels of the garments ensuring air circulation. sometimes three dimensional vents attached on
the garment for improving the body ventilation.

21. Garment ventilation apertures with cover flap:
This is a improved version of protective shield ventilation system. The mesh is remain
underneath the flap. This flap is adjustable according to the needs.
Garment with structural vent:
This is a scoop-like airflow design on the jacket which was worn for motorcycling , when the
wearer bent down to control the motorcycle, the air could enter from the scoop located at the
shoulders, thus taking the body heat and moisture vapor out of the back hem of the jacket.

22. Garment with comprised of cords:
This Garment design to increase the air circulation between the skin surface and the
garment. To improve air circulation at the body surface, garments are designed to keep a
distance from the skin surface.
The garment was comprised of cords, comparatively open warp knit fabric at the inner
surface of the garment. The inventor placed the cords vertically and bound them with the
base knit fabric to create a plies of vertical air channels.

23. Wearable devices is modern addition in the fashion fields. It can play a significant role in
thermal comfort system. This devices works in three main basic systems.
Air cooling system
Liquid cooling system
Ice or cold pack System
This systems are being used in astronauts, fighter jet pilots, explosive disposal army, fire
fighters, formula one (F1) racing car drivers, mine workers dresses.

24. Air cooling system:
During hot weather, people used electric fans to keep the body cool before the invention of air
conditioning systems. The fan system has been adopted in the garment system for specific
occasions. Normally these fans are lightweight and small enough to be installed on the garment.
Ice or Cold Pack System:
This system uses ice or a gelled coolant to keep the body cool. the ice packs or
gelled coolants require replenishment. It is not suitable for daily use.

25. Liquid cooling system:
Liquid cooling systems require a fluid reservoir, a circulating pump and connecting hoses which
attach to the garments. The cooled liquid is circulated through the garment and then returned to
the reservoir for re-chilling. This circulated mechanism provides lower temperatures to the
wearer.

26. The HSE states that 20% of the workforce is in discomfort and not working to their full
ability. There is big potential for this field of garments thermal comfort.
In applying the different approaches for improving the thermal comfort of clothing, the
designer should take a holistic view and be creative in maximizing the functionality of the
garment without compromising other important factors such as aesthetics, cost, etc.
So far work has been done for increase of thermal comfort is used mostly in functional
purpose. There are huge area of development in this subject.