Document adEm2m0EGRN2dpK2aY01MX3B

17.4 CHAPTER 8 1946.Guide stripping, sealing and caulking may reduce infiltration to the point that special openings must be provided to supply, adequate air to the heating appliances. REFERENCES *--A.S.H.V.E. Research Reports No. 786--Infiltration Through Plastered and Unplastered Brick Walls, by F.C. Hougbten and Margaret.Ingels (A.S.H.V.E. Transactions. Vol. 33, 1927. p. 377). No. 826--Air Infiltration Through Various Types of' Brick Wall Construction, by G. L. Larson. D. W. Nelson and C. Braatz (A.S.H.V.E. Transactions, Vol. 35, 1929. p. 183). No. 851--Air Infiltration Through Various Types of Wood Frame Construction, by G. L. Larson. D. W. Nelson and C. Braatz (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 99). *--A.S.H.V.E. Research Reports No. 686--Air Leakage, by F. C. Houghten and C. C. Schrader (A.S.H.V.E. Transactions,'Vol. 30, 1924, p. 105). No. 704--Air Leakage Around Window Openings, by, C. C. Schrader (A.S.H.V.E. Transactions, Vol. 30. 1924, p. 313). No. 803--Air Leakage on Metal Win dows in a Modern Office Building, by F. C. Houghten and M.' E. O'Connell (A.S.H.V.E. Transactions. Vol. 34, 1928. p. 321). No. 815---Air Leakage Through a Pivoted Metal Window, by F. C. Houghten and M. E". O'Connell (A.S.H.V.E. Transactions, Vol. 34,1928, p. 519). No. 817--Effect of Frame Calking and Storm Sash on Infiltration Around and ThroughWindows, by W. M. Richtmann and C. Braatz (A.S.H.V.E. Transactions, Vol. 34, 1938, p. 547). No. 909--Air Infiltration Through Double-Hung Wood Windows, by G. L. Larson. D. W. Nelson and R. W. Kubasta (A.S.H.V.E. Transactions. Vol. 37. 1931. p. 571). The Weathertightness of Rolled Section Steel Windows, by J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions, Vol. 34, 1928, p. 527). Pressure Differences Across Windows in Relation to Wind Velocity, by J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions,-Vol. 36,1930, p. 83). Air Infiltration Through Steel Framed Windows, by D. O. Rusk, V. H. Cherry and L. Boelter (A.S.H.V.E. Transactions. Vol. 39. 1933, p. 169). s--Fuel Saving Resulting from the Use of Storm Windows and Doors, by A. P. Kratz and S. Konzo (A.S.H.V.E. Transactions, VoL 42. 1936. p. 87). The Infiltration Problem of Multiple Entrances, by A. M. Simpson'and K. B. Atkinson (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, June, 1936. p. 345). Infiltration Characteristics of Entrance Doors, by A. M. Simpson (Refrigerating Engineering, June, 1936). '' *--A.S.H.V.E. Research Reports No. 994--Wind Velocities Near a Building and Their Effect on Heat Loss, by F. C. Houghten, J. L. Blacksha'w and Cari Gutberlet (A.S.H.V.E. Transactions, Vol. 40, 1934. p. 387). No. 1069--Heating Requirements of an Office Building as Influenced by the Stack Effect, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E.-Transactions, VoL 43, 1937, p.,437). Flue Action in High Buildings, by H. L. Alt (A.S.H.V.E. Journal Section, Healing. Piping and Air Conditioning. May, 1932, p. 376). Influence of Stack Effect on the Heat Loss In Tall Buildings, by Axel Marin (A.S.H.V.E. Transactions, VoL 40,1934, p. 377). '/ * ^"Neutral Zone In Ventilation, by J. E. Emswiler (A.S.H.V.E. Transactions, VoL 32, 1926, p. 59). CHAPTER 9 jciturai ^Uentifation Wind Forces, Temperature Difference forces. Heat Removal, Openings, Windows,. Doors, Skylights, Roof Ventilators, Stacks, Principles of Control, General Rules, Dairy Barn Ventilation, Garage Ventilation VENTILATION by natural forces finds application in industrial plants, public buildings, schools, dwellings, garages, and in farm buildings. . The natural forces available for moving air into,, through and out of buildings are: (a) wind forces, and (>) the difference in temperature between the air inside and outside a building. The air movement may be caused by either of these forces acting alone or by a combination of the two, depending upon atmospheric conditions, building design and loca tion. The ventilating results obtained will vary, from time to time, due to variation in the velocity and direction of the wind and the temperature difference. The arrangement, location, and control of the ventilating openings should be ' such that the two forces act cooperatively rather than in opposition. WIND FORCES In considering the use of natural wind forces'.for producing ventilation, account must be taken of:.(l) average wind velocity, (2) prevailing wind direction, (3) seasonal and daily variations in velocity and direction, and (4) local wind interference by nearby buildings, hills or other obstructions of similar nature. Values are given in Table 2, Chapter 15 for the average summer wind velocities and the prevailing wind directions in various localities through out the United States, while Table 1, Chapter 14, lists similar values for the winter. . In almost all localities the summer wind velocities are lower than those in the winter, and in about two-thirds-of the localities the prevailing direction is different during the summer and winter. While the tables give no. average velocities below 5 mph, there will be times when the velocity is lower, even in localities where the seasonal average is con siderably above 5 mph. There are relatively few places where the velocity faffs,below one half of the average for many hours per month. Con;sequently, if the natural ventilating system is designed for wind velocities of one-half of the average seasonal velocity, it should prove satisfactory in almost every case. Equation 1 may be used for calculating the quantity of air forced through ventilation openings by the wind, or for determining the proper size of such openings to produce given results: where Q = EAV (1) Q = air flow, cubic feet per minute. A = free area of inlet openings, square feet. V = wind velocity, feet per minute, = miles per hour X 88. - E = effectiveness of openings. (E should be taken at 0.50 to 0.60 for.perpendicular winds and 0.25 to 0.35 for diagonal winds1.) The accuracy of the results obtained by the use of Equation 1 depends upon the placing of the openings, as the formula assumes that ventilating t 175