Hygienic Assessment of Summer Clothing Fabrics for a Hot, Dry Climate
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UDC 613.481:551.582(213.52)
N. K. Khamraeva
Hygienic Assessment of Summer Clothing Fabrics for a Hot, Dry Climate
Tashkent Branch of the Central Research Institute of the Clothing Industry
Our investigation of 50 types of summer fabrics showed that their structural characteristics and properties differ in significance. In most cases, each fabric type has one or two highly rated properties; in other words, although a fabric may be considered hygienic because of a particular characteristic, its other qualities do not meet the requirements placed on it. At the same time, it is impossible to objectively assess a fabric’s hygienic suitability on the basis of several structural characteristics and properties simultaneously. Assessing the hygienic suitability of a textile material on the basis of only one of these is unacceptable, since it fails to take into account other qualities that are no less important to the assessment. Analysis of the values of each structural characteristic and property of the fabrics showed not only the importance of each, but also their interdependence—
Table 1
Relationship between structural indicators and fabric properties
| Indicator or property | Degree of correlation of porosity with other structural indicators and fabric properties | Indicator or property | Degree of correlation of total moisture permeability with other structural indicators and fabric properties |
|---|---|---|---|
| Volumetric filling | −0.96 ± 0.01 | Volumetric filling | −0.17 ± 0.14 |
| Warp density | −0.58 ± 0.11 | Warp density | −0.52 ± 0.11 |
| Pore filling | −0.61 ± 0.10 | Pore filling | −0.58 ± 0.11 |
| Air permeability | −0.60 ± 0.10 | Air permeability | −0.49 ± 0.12 |
| Vapor permeability | −0.40 ± 0.14 | Vapor permeability | −0.63 ± 0.10 |
| Hydrophilicity | −0.96 ± 0.01 | Hydrophilicity | −0.39 ± 0.10 |
| Hygroscopicity at 100% relative humidity | −0.40 ± 0.13 | Hygroscopicity at 100% relative humidity | −0.52 ± 0.01 |
| Hygroscopicity under natural conditions | −0.68 ± 0.09 | Hygroscopicity under natural conditions | −0.62 ± 0.11 |
| Maximum water capacity | −0.57 ± 0.11 | Maximum water capacity | −0.36 ± 0.10 |
| Minimum water capacity | −0.56 ± 0.11 | Minimum water capacity | −0.23 ± 0.15 |
| Total moisture permeability | −0.90 ± 0.03 | Porosity | −0.90 ± 0.03 |
| Moisture drying rate | −0.90 ± 0.03 | Moisture drying rate | 0.04 ± 0.16 |
| Capillarity | −0.39 ± 0.10 | Capillarity | −0.36 ± 0.10 |
…[[unclear: end of word]]. Consequently, a change in some fabric indicators and properties entails a deterioration or improvement in others.
Accordingly, to assess the hygienic properties of fabrics objectively and select optimal materials for making rationally designed clothing, it is necessary to establish the minimum number of structural characteristics and properties required and to determine their optimal values.
The investigations showed that, among the 14 structural indicators and properties characterizing the hygienic properties of fabrics and their behavior with respect to air, vapor, and moisture (sweat), the material’s porosity and total moisture permeability are most closely interrelated and exhibit the greatest correlation with the other characteristics and properties (Table 1). Both indicators may be termed “primary.”
On the basis of the investigations, all 14 structural indicators and properties of fabrics were divided into five groups according to their values. Calculation of the statistical significance of the differences between the mean values for adjacent groups showed that the differences were substantial in every case. This provides grounds for considering the groups optimal, sufficiently precise for characterizing the hygienic properties of a material, and suitable for practical use in studying the quality of textile materials.
The optimal values of fabric porosity and total moisture permeability according to the degree of hygienic performance are given in Table 2.
Assessment of the hygienic properties of clothing fabrics requires their determination using the two primary indicators. It may be carried out by the following method. By convention, each of the five fabric groups, classified according to hygienic performance, is assigned the same numerical score as its group number. The hygienic performance of a fabric is assessed by the sum of the scores for the primary indicators. A fabric receiving fewer than 6 points is considered to have “low” hygienic performance, while one receiving 6 points or more is considered to have “good” hygienic performance.
To verify the objectivity of the fabric assessment, equal numbers of men’s shirts were made from various textile materials with “low” and “good” hygienic performance. The shirts were of medium size and height, with set-in long sleeves and buttoned cuffs, a full-length front fastening, and a set-in collar without a stand. Physiological studies of the thermal state of subjects wearing these shirts were conducted in a climatic chamber
Table 2
Grouping of optimal values of fabric indicators and properties
| Indicator | Unit of measurement | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 |
|---|---|---|---|---|---|---|
| Porosity | % | Up to 49.9 | 50–69.9 | 70–89.9 | 90–109.9 | 110 and above |
| Total moisture permeability | g/m² | Up to 40.9 | 41–48.9 | 49–56.9 | 57–64.9 | 65 and above |
(2.5 × 2.5 m) at an ambient temperature of 36–38° and a relative humidity of 30–40%. The subjects sat on chairs in the center of the chamber. The difference between the chamber wall and air temperatures was 1–2.5°. The experiment lasted 6 hours. White cotton coats were used as the control clothing. At the beginning, the subjects’ pulse rates were the same (72–75 beats per minute). By the end of the experiment, pulse rate had increased by 7 beats per minute in subjects wearing the control clothing, by 10 in those wearing clothing with a “good” hygienic rating, and by 27 in those wearing clothing with a “low” rating. Increases in mean weighted skin temperature and moisture, and in the humidity and temperature of the air beneath the clothing, were in all cases greater for clothing with a “low” hygienic rating than the corresponding increases for the control clothing and clothing with “good” hygienic properties.
A survey of the subjects’ thermal sensations showed that they were initially comfortable. At the end of the experiment, respondents wearing shirts made from fabrics with “good” hygienic properties and those wearing the control clothing perceived no substantial difference in their thermal sensations. They were alert, felt comfortable, and experienced coolness in the back region. Subjects wearing shirts made from fabrics with “low” hygienic properties described their condition as “hot” and “stuffy.” They reported feeling lethargic; toward the end of the experiment they began to develop headaches and wanted to take off their shirts and free their necks, shoulders, and forearms from clothing.
Conclusions
- The method developed permits a sufficiently accurate assessment of the hygienic properties of fabrics and has practical value. It can be applied by fashion design houses and garment industry enterprises when selecting suitable clothing fabrics and developing new types for the country’s hot, dry climate.
- The principal structural characteristics and properties of fabrics most closely related to the main ones were identified.
- Optimal structural characteristics and properties were established that make it possible to determine the suitability of fabrics for summer use in a hot, dry climate.
- Fabrics containing chemical fibers have “low” hygienic properties, as reflected in changes in human thermoregulation.
- The best fabrics for summer use in a hot, dry climate are those made from natural and manufactured fibers, or blends thereof, with plain, crepe, or twill weaves and high porosity and total moisture permeability.
Received September 11, 1973.