Linens

Underwear. Underwear is clothing that comes into direct contact with the body and covers up to 80 percent of the skin’s surface. Underwear affects the temperature and moisture of the skin as well as the air layer adjacent to it. Underwear fabrics must not hinder normal skin functions; they must be moisture absorbing, air permeable, and moisture retentive so that they do not hamper the excretion and evaporation of perspiration and gaseous substances and do not cling to moist skin. They must be soft, lightweight, and elastic, as well as nonirritating to the skin. These fabric qualities must be retained while the underwear is being worn, when it is moistened or soaked, and after it is laundered. Cotton fabrics and knitted fabrics are best for manufacturing underwear; they absorb and give off moisture quickly, and they hold up after many launderings without losing their qualities.

Good hygienic properties are possessed by underwear which is made from fine linen cloth, especially during hot periods, because of its good moisture retention, its capacity for allowing evaporation, and its cooling effect. Natural silk fabrics differ little from cotton fabrics in their properties, but underwear manufactured from them is less strong. Underwear made from synthetic silk (acetate or rayon) approaches cotton underwear in its properties, but it evaporates moisture less effectively, does not warm the body, and sticks to moist skin. Moreover, underwear made from acetate fibers is electrostatically charged, which may cause unpleasant sensations.

Knitted underwear made from synthetic fibers—chlorinated polyvinyl chloride fibers—has good heat-protective properties; it allows moisture to evaporate yet remains dry. This chlorinated-fiber underwear is especially recommended for wear during the cold season. Such underwear is called therapeutic because it eases the pain of diseases of the joints, muscles, and peripheral nerves as a result of its electrostatic charge, a property of fabrics made from polyvinyl chloride fibers. Woolen underwear absorbs moisture poorly, dries slowly, and may irritate the skin. It is recommended as a second layer of underwear in cold periods.

After underwear has become soiled by secretions from the skin and dust from the air, its hygienic qualities are less effective: after a week’s wear the air permeability of underwear decreases by 15–20 percent, its weight increases by 5–10 percent, and the quantity of mineral substances increases four to five times over. While it is being worn, underwear is subject to the spread of bacteria and to the spread of any parasites that may be present.

Bedclothes. Sheets, pillowcases, and blanket covers, as well as towels and handkerchiefs, are subject to the same hygienic requirements as underwear linens.

Table linens. Tablecloths and napkins are made of cotton, linen, silk, and synthetic fabrics.