PROTECTING SCREENS — grids for protection of the person against stings of insects and mites or to interfering penetration of the flying insects and rodents into inhabited, production and other rooms. Distinguish grids for individual and group protection. The protective effect of grids is based on mechanical (close-meshed grids) or the chemical principle (the coarse grids impregnated with the frightening-off substance — a repellent).
For individual protection from stings blood-sicking flies (see) and mites (see) apply 3. page from tulle or a gauze — mosquito nets (muskiter), capes, bed curtains and from fishing put (networks) — the bed curtains which are frightening off Pavlovsky's grids.
Mosquito nets serve for protection of the person and a neck. They are sewed from tulle with cells no more than 1,5 mm for protection from stings of mosquitoes, and from mosquitoes, midges and mokrets — with the cells which are not exceeding 0,7 mm. For the best visibility in a mosquito net in the face of sew a piece of black tulle or the metal gauze. The shortcomings of mosquito nets limiting use with them are their relative bulkiness, difficulty of work in hot weather, easing of visual acuity and hearing.
Capes for protection of a neck and the person are produced from a piece of tulle 35 cm long and 80 — 100 cm wide. Impregnated repellents (see) a cape becomes stronger on a headdress or under it by means of a narrow linen elastic band and freely overhangs around the head, leaving the person open.
Bed curtains use at a lodging for the night (rest), especially in the open air, in places with a large number of blood-sicking flies. Bed curtains sew from a gauze, tulle or fishing put. They can be rectangular (width of 80 — 100 cm, 200 — 250 cm long and 125 — 150 cm high) or cone-shaped. The cone-shaped bed curtains is suspended only for one upper loop (fig. 1). The bed curtains is pulled over a bed so that its bottom edge fell by 25 — 30 cm below a mattress. Bed curtains from fishing put (cells of 1,5 — 2 cm), impregnated with repellents, limit access of air, than bed curtains from a gauze or network much less, but they constantly emit vapors of repellent, to-rymi the person who is under bed curtains should breathe.
The frightening-off Pavlovsky's grids — grids on which the frightening-off substances are applied are offered in 1938 to E. N. Pavlovsky, G. S. Pervomaysky and K. P. Chagin for protection against attack of blood-sicking flies. The grid represents a rectangular piece of cotton fishing share 50 X X 75 cm in size with cells in 1 — 1,5 cm; edges sheathe it a band with the free ends (ties) on the one hand. The grid is dressed on a headdress so that its edges laid down on shoulders and a back, and in front hanged down to eyebrows (fig. 2). The grid is fixed on a headdress by the ends of a band or they are tied under a chin. Couples of repellent which are allocated from a grid form around it and in the face of the protective belt which is frightening off blood-sicking flies. For the long frightening-off action of a grid of Pavlovsky soak with so-called repellent jellies which prepare 1 weight by dissolution. h cellulose acetate in 11 h acetone with the subsequent addition 4 weight. h repellent (dimethyl phthalate, diethyltoluamide, geksamid or other). In the formed gelatinous weight presoak grids; the frightening-off action of grids remains 3 — 4 months.
For group protection 3. pages can be used in tents, dugouts, blindages, etc. Strips fishing put (width apprx. 50 cm), soaked with repellent jellies, attach to an entrance panel and on perimeter of the basis of a tent (fig. 3). The same grids veil doors, windows and other openings of blindages and other constructions.
Windows, doors and air vents of inhabited and production rooms for protection against the flying insects zasetchivat metal (fig. 4) or a kapron grid. Metal 3. page with cells no more than 5 cm 2 zasetchivat air vents and windows of basements for protection against penetration of rodents in them.
See also Clothes protective .
Bibliography: The multivolume guide to microbiology, clinic and epidemiology of infectious diseases, under the editorship of H. N. Zhukova-Verezhnikov, t. 5, page 495, M., 1965; The Guide to medical entomology, under the editorship of V. P. Derbene-howl-Ukhova, page 312, M., 1974.
K. V. Krashkevich.