Quality Assurance Exam II Comfort Human comfort Comfort is freedom from pain freedom from discomfort It is a neutral state Comfort is a pleasant state of physiological psychological and physical harmony between a human being and the environment What comfort really is Relative Psychological physiological thermal sensorial mobile Subjective Psychological comfort implies that individuals need specific garments fabrics colors and design features to help them feel confident and at ease within the context of the various roles they assume Factors o Self image o Relationship with others trust love and respect o Need of privacy solitude silence anonymity Physiological comfort refers to maintenance of thermal balance the proper relationship between body heat production and loss Factors o Cardiovascular system o Skeleto muscular system o Central nervous system o Pulmonary system o Digestive system o Thermoregulatory mechanism Physical aspects of comfort refer to different sensations and feeling of discomfort and or pain which influence the two types of comfort Factors o Touch sight hearing taste smell Comfort related physical properties of textiles Thermo physiological comfort o Thermal resistance o Water vapor permeability breathability o Wickability o Sorption of water o Water resistance repellency and proofness o Drying rate Sensorial Neuro physiological comfort o Prickliness itchiness inflammation o Roughness o Thermal character warm cool feeling o Electrostatic propensity Body movement comfort o Stretch o Weight o Pressure compression Hand A tactile sensation may be by touch or sight we will be using touch Usually a subjective assessment affected by Subjective hand rating the fabric on scale of 1 7 based on the following o Body temperature o Room temperature o Psychological state of being o Physiological state of being o Association o Pliable to stiff o Stretchy to non stretchy o Springy to limp o Smooth to rough o Compact to open o Cool to warm o Harsh to slippery o Soft to hard Fabric Drape o The manner in which a fabric hangs falls over a 3 dimensional form o How a fabric bends under its own weight is an indication of drapability o Drape occurs when only part of the fabric is directly supported and gravity produces deformation in the unsupported portion o Fabrics that fall in numerous vertical folds are highly drapeable o There is not a standard requirement you have to make a judgment call o The range is 0 100 called the drape coefficient o Generally above 50 is considered stiff and not very drapeable o Some fabrics are considered not drapeable most denim for jeans for example What affects drapability 1 Fiber content a Some fibers are more stiff than others depends on size and inherent characteristics b Rayon is known for drapability 2 Yarn structure a Tightly constructed yarns will have less drapability b Loosely constructed yarns will have more a High fabric count makes a compact structure which will likely have 3 Fabric structure less drape b Combination of fabric structure and yarn structure c ASTM 4964 D 3107 D 6614 Moisture Absorbency absorbate o Ability of material absorbent to take in or absorb another material o Ability to retain liquid water in interstices pores and internal portions o Evaluate how quickly liquid absorbed and quantity absorbed at saturation point o ASTM D 4772 AATCC 79 Water Repellency Water Resistance and Waterproof o Water repellency relative resistance of material to surface wetting water penetration or water absorption o Water resistance ability of material to withstand penetration by water under pressure or water that drops from distance and strikes against material with known force o Waterproof materials resistant to water penetration regardless of pressure or force o AATCC 22 Repellency AATCC 35 Resistance Water Vapor Transmission o Speed with which water vapor passes through material o Desiccant method known weight of dried calcium chloride placed in container covered by material weight gain o Water method specimen covers pan containing known amount of water water loss by evaporation measured o Both procedures measure water transmitted in 24 hour period Physical Characteristics of Textile Materials Influencing Thermal Comfort o Fabric mass o Fabric thickness o Fiber yarn and fabric structures o Porosity as a percentage is the ratio of air space to the total volume of the fabric expressed o Cover factor is defined as the opacity or hiding power in textiles The Physics of Human Comfort o Body metabolism o Heat transfer o Evaporation Heat Transfer o Heat transfer refers to the transfer of heat energy from one environment to another Heat transfer occurs whenever a temperature difference T exists between two environments heat moves from the warmer surface or area to the cooler surface or area o The rate at which heat is transferred depends on T as well as any resistance imposed between the two environments o Modes of heat transfer o Conduction is the transfer of heat by physical contact either within a body or between two touching bodies o Convention is heat transfer via a moving air mass within space o Radiation involves heat transfer through space in the form of electromagnetic energy o Effect of fabric properties on heat transfer o Fiber type and structure o Yarn type and structure o Fabric type and structure o Finished applied o Standard Test Methods o CAN CGSB 4 2 NO 70 1 94 Thermal insulation performance of textile materials o ASTM D 1518 95 Thermal transmittance of textile materials Thermal Insulation cold plate hot plate Procedure 1 specimen cold plate specimen hot plate Procedure 2 Electrostatic Propensity charge o Measure of capacity of non conducting material to acquire and hold electrical o ASTM 4238 Electrostatic propensity of woven fabrics AATCC 76 electrical resistivity of fabrics AATCC 84 electrical resistivity of yarns o AATCC 115 electrostatic clinging of fabrics fabric to metal test o Electrostatic cling propensity of one material to adhere to another because of surface electrical charges o Time required for charge to decay so that electrical attractive forces causing specimen to cling to metal surface are overcome by gravitational forces pulling specimen away o AATCC 134 electrostatic propensity of carpets record build up after being walked on Anti Static Finished o Conditions for static electric charge build up are cool dry environment o Manufactured fibers build up static electric charges because they are hydrophobic and do not