Prof. (Dr) S.D. Asagekar, Prof (Dr) U.J. Patil, Mr. Avinash S. Powar*
DKTE’S Textile and Engg. Institute, Ichalkaranji.
ABSTRACT
This article reports the high altitude nonwoven jacket and its applications. The high altitude clothing mainly used in jacket, waist coat, trousers, glacier cap, rappelling gloves and glacier gloves. The function of high altitude fabric is protection against extreme cold climate, wind chill factor and this fabric gives better comfort.
Keywords: Nonwoven, High altitude, Thermal insulation, Comfort, etc
INTRODUCTION
High altitude clothing is used for very cold climatic conditions like extremely low temperature, high velocity winds, snow fall etc. especially in critical armed forced areas like Siachin. The high altitude clothing needs to meet both purpose and a person’s feelings of grief or distress. High altitude clothing is also known as extreme cold climate clothing (ECC). The high altitude clothing consists of jacket, waist coat, trousers, glacier cap, rappelling gloves and glacier gloves.
A battery heated jacket has been manufactured using same concept used in heated gloves involving heating tapes, temperature controller and light weight rechargeable battery. The jacket has manufactured which multi- functional layers each is contributing to physical, mechanical and thermal resistance, and also heat vapor transmission properties.
The highest point on the Earth is Mount Everest. The mountain’s peak is so high in the Earth’s atmosphere that the amount of oxygen is much lower than at sea level. The altitude’s combination of little oxygen, strong winds, and frigid temperatures keeps the existence of plant and animal life to a minimum.
In textile field high altitude is nothing but to produce a fabric for controlling such type of evidence and give comfort to human being in extreme conditions. That type of fabric to maintain the continuous body temperature to the normal level. [1,2,3]
Metabolism of heat with human body:
The persons linking and disliking for cold and warm conditions and so the endurance level or point for cold and warm climate may also vary to some extent, but there are certain level or point beyond which all human beings which cannot bear extreme low temperature. A number of studies have been conducted to express this endurance point or level so that clothing, equipment’s, shelters, etc. may developed accordingly. It has been taken out that the mean skin temperature of human beings at rest position and are thermally comfortable is approximately 33° C, and metabolic heat generation at this point is 150 watts. In cold conditions, body generates more thermal energy by physical efforts and shivering to balance the temperature difference. The effects and causes of high altitude were raised by India in 1965 in the common wealth conference on defense clothing’s subsequently, a number of experiments were taken up to understand and understand these effects. [8,9]
Factors affecting on protection of human body in a cold environment:
- Metabolic heat.
- Wind chill.
- Thermal insulation.
- Air permeability.
- Moisture transmission.
1. Metabolic heat: The heat output due to metabolism depends on the body measurements as well as the activity involved. This heat output would be less at rest and high during hard work.
Metabolic heat production calculated from oxygen consumption, dry heat loss measured in a calorimeter, and body temperature measured by telemetry. [8]
2. Wind chill: A still- air temperature that would have the same cooling effect on exposed human skin as a given combination of temperature and wind speed called also chill factor or wind-chill factor. Wind chill depends on the temperature as well as speed of the wind.
3. Thermal insulation: Thermal insulation is the reduction of heat transfer between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable objects shapes and materials.
The protection against cold is depends on thermal resistance or thermal insulation of garment or clothing. [11]
4. Air permeability: In general, a wearer would be more comfortable with a fabric of more air permeability than with a fabric of less air permeability. However, the openness of fabric structure would increase the effect of wind chill. The thermal resistance obtained in normal air with a fabric of a particular structure would be unaffected even in cold wind if the air permeability is more.
5. Moisture transmission rate (MTR), also water transmission rate (WTR): is a measure of the passage of water vapor through a substance. There are many companies where moisture control is critical. Moisture sensitive foods and pharmaceuticals are put in packaging with controlled MTR to achieve the required quality, safety, and shelf life. In fabric, MTR as a measure of breathability has contributed to more comfort for wearers of fabric for outdoor use.
Component Materials for Protective Clothing
The protective clothing is generally composite multilayered garments developed in view of different reasons mentioned above. Each of the component materials for these composite garments has a specific role to play and so their roles, requirements and expected performance are necessary to be discussed.
1.1 Outer fabrics:
The outermost cover for many of the protective clothing and accessories should create an obstacle for wind and provide moisture vapor transmission so that the wearer is comfortable and protected from wind chill and related factors. The choice depends on lightweight coated fabrics. The coatings act as a wind obstacle. After trial with different weight, types and classes of coatings, the polyurethane coated nylon fabric has been found to provide to give the ‘wind obstacle’ effect with flexibility and lightness of the basic fabric. The Goretex which has a breathable micro porous polyurethane coating is also used for special breathable protective clothing.
1.2 Reflective Inner Liner:
The experienced were made to check the effect of heat loss with various liners. It was seen that 13 a reflective liner like aluminum foil placed at a distance of 8 mm from woolen gabardine showed reduced in heat losses to the extent of 27%. This has set way for the use of reflective material to increased thermal insulation properties. At present, aluminum foil is becoming famous for such applications. The knitted light weight nylon fabric laminated with aluminum film is used for thermal insulation in the protective clothing.
1.3 Thermal Insulating Materials:
The woolen piles and fabrics which are generally useful for other regions are not sufficient to meet the requirements of the extreme cold region. For this purpose, in other countries the down feathers of good quality are successfully used, but the down feathers of Indian birds do not provide the required warmth, more probably due to the climatic conditions prevailing in the area. Acrylic pile fabric is also very useful due to its good dimensional stability, low rate of creep and lower moisture absorption than that of wool. New advancement of fiber technology has introduced a number of synthetic insulating materials IS. Some of them are Thinsulate, Thintech, Primaloft, Thermoloft, Hydrofil and Goretex.
1.4 Multilayered Clothing:
The thermal resistance of a single layered Fabric would depend on the raw material and cumulative resistance effect of the layer of clothing, air aside to textile material, and the air in between skin and fabric layers. When the clothing is made of a multilayered fabric, these effects would get further increased due to the resistance of fabric layers, air entrapped in between various fabric layers and air trapped in between skin and textile assembly. Hence, Single layer fabric gives less protection than multi-layer fabric.
The types of layer used are as follows:
a. Base layers like merino wool or polyester better warmth and wicking properties for both cold, and hot climate comfort, and are the anchor of your layering system.
b. Mid layers can be used depending on increases and decrease in temperature change. Their primary purpose is temperature maintained.
c. Outer Layers are designed to keep the harmful effects of weather, like wind and precipitation (rain and snow) from getting to your warm layers. A belay layer is also many times common place for mountains and ice climbing and when individuals are not moving, hence not producing their own warmth. These are normally very large and soft insulated jackets so the stationary belay layer doesn’t get too cold while belaying the climber.
Applications:
a. Jackets
The high altitude jackets are normally three-layers. The inner layer looks like waist coat and it is made of acrylic pile fabric. Second layer is an insulating liner composition of polyester batting and aluminum fabric. For preventing the heat loss of body the aluminized surface is used. The outermost layer is to control the wind and it is made up of polyurethane coated nylon fabric.
b. Trousers
The high altitude trousers are two-layered clothing. The inner layer is insulating and it is assembly and double layered. It composed of two layers one is of polyester batting and another is of aluminum fabric, siliconised nylon fabric is used for sandwiches both layers. The outermost layer is to control the wind and it is made up of polyurethane coated nylon fabric.
c. Caps
The fluoro-chemical treated nylon fabric having flame, water and oil repellency is used for made up of outer part of the cap. The inner portion of cap is lined with acrylic pile fabric.
d. Gloves
In extreme cold condition, three sections of gloves on the principle of the action are more favorable. Heat losses involved in the five fingered gloves are higher due to a number of limit extremities of fingers coming into contact. The three sections are as thumb, fore finger and remaining three fingers. The outer layer of face side of glove is made up of polyurethane coated nylon. The inner side is made up of soft variety of Napa leather. An inner layer of acrylic pile is used for insulation in these gloves. Polyester batting is used on the face side for further added insulation. [4, 5, 6]
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8. Metabolic heat production, heat loss and the circadian rhythm of body temperature,
2003 May;88(3):423-9. Refinetti R Experimental Physiology
9. Frank P. Incropera; David P. De Witt (1990). Fundamentals of Heat and Mass Transfer (3rd ed.). John Wiley & Sons. pp. 100–103. ISBN 0-471-51729-1.
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12. https://www.ittaindia.org/protective-textiles
