Document 1gvOGQ5027gv51okRZ9bD6NrK

American Society of Heating and Ventilating Engineers Guide, 1928 weather. In.hotel, theater, etc., cooling work recirculation will conserve heat in winter and refrigeration in summer. The development of the science of air conditioning has been rapid and the textile industry has derived great benefit from the adoption of adequate systems. Its applications are wide entering somewhere into every process in making of articles used every day, such as clothing, candy, meat products, and a host of others. Mass production of uniform quality products has been made possible and has placed manufacturing schedules on a year round basis for many industries. It has also improved conditions of comfort and permitted the operation of theaters and other assembly places every day of the year contributing greatly to the health comfort and wealth of the nation. \ 328 Chapter XXIV OZONE IN VENTILATION OZONE is a normal constituent of pure, natural air and its quantity varies with the topography of the country, particularly with regard to the altitude, the presence of bodies of water, and certain plant life. Ozone is produced, photo-chemically, by ultra-violet light of short wavelength (120-180 (jl(a), while light of greater amplitude (300-330 pp.) exerts a decomposing effect. At high altitudes, where short wave radia tions are more intense, ozone naturally occurs in greater quantities. It is continuously under the destructive effect of longer waves, however, but a dynamic equilibrium is finally reached between the rate of formation and the rate of decay, which shifts with the altitude. Since light of longer wave length penetrates closer to the earth than does that of shorter amplitude, the equilibrium becomes favorable to ozone directly as the altitude. In summing up the evidence at hand it may be concluded that ozone, while mostly absent from city air, is normally present in pure country air, but in amounts that are difficult to estimate accurately. In nature the air is continuously under ionizing influences, and the enclosing of air, as in buildings, excludes these influences, in addition to destroying the original ionization of the air. Ionization is involved in chemical activity. The process of ozonizing, in addition to supplying ozone, ordinarily absent from city air, further provides considerable ionized oxygen, producing a fresh, chemically active air, comparable with fresh, pure air of nature. Physical Properties Density--Observed Values; 1.657 (Otto, Direct weight method). 1.717 (Soret, by diffusion). Calculated Value; 1.66 The foregoing^ values refer to air as unity. Its rate of diffusion, with respect to oxygen is 0.75. Heal of Formation--The production of ozone is an endothermic reaction, the heat of formation being 34,000 calories per gram molecule (Jahn, Zeit. Anorg. Chem. 68, 250; 1910). Boiling Point --112 deg. cent. (International Critical Tables, 1926). At a temperature of 270 deg. Cent. (518 deg. fahr.), Ozone is instantly decomposed. Odor--Strong, penetrating and characteristic. Perceptible to the sense of smell in concentrations above 0.01 p.p.m. by volume (Hill & Aeberly, Heating and Ventilating Magazine, December, 1921). Olfacty (minimum perceptible concentration expressed in molecules per c.c.) 2.705 X 10s at 0 deg. cent, and 760. Solubility--Soluble in water and dilute acids, quite soluble in carbon tetrachloride and many vegetable oils. Its solubility in water, like all gases, is dependent upon the temperature and partial pressure. Nernst (Festschrift, 391; 1912) gives the solubility coefficient for water, at Compiled especially for The Guide by Frank E. Hartman, Chicago, III. 329