Ventilation for Dwellings, Rural Schools and Stables

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...and sixth columns have their temperature difference equivalents computed and given in the fourth and seventh columns, these being used with the formula named. Computed theoretical flow of air through a flue one square foot in crosssection and 40 feet long, due to the direct impact and auction effect of wind at different velocities. If the flow of air through a ventilating flue 40 feet high and one square foot in cross-section, as given in the two tables, is compared it will be seen that differences of temperature inside and outside the flue ranging from one degree to sixty degrees F. are associated with computed air movements increasing from some 8,000 cubic feet with a difference of one degree P. to 63,000 cubic feet per hour when the difference in temperature is 60 F.; while wind velocities ranging from one mile to nine miles per hour, acting by direct impact, and of two miles to twelve miles per hour acting by suction, give approximately equal rates of flow. If the actual velocities were one-half these computed amounts the slowest rate of movement would a little more than meet the needs of one cow while the most rapid movement would permit a flue one square foot in cross-section to supply nine cows at the rate designated on page 41, 3,542 cubic feet per hour. Such a rate of movement, too, through a flue one-fourth of a square foot in cross-section would, at one half the slowest rate, supply air to 2 persons, and, at one-half the fastest rate, to 15 persons. The wind velocities which are effective in producing draft in dwellings and stables probably do not have a yearly average in most parts of the United States greater than four to six miles per hour. Taking the average flow due to impact equal to that computed for the four mile wind, and that due to suc...