Document p2vOBZqBN5ek1dZ3ed1NnE08B

168 CHAPTER 8 1949 Guide sealing and caulking may reduce infiltration to the point that special open; ings must be provided to supply adequate air to the heating appliances. REFERENCES 1 A.S.H.V.E. Research Report No. 786-^InfiItration Through Plastered and Unplastered Brick Walls, by F. C. Houghten 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 Brick Wall. Construction, by G. L. Larson, D. W. Nelson and C. Braatz (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 99. No. 868--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. 397). * 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 Windows 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 Through Windows, by W. M. Richtmann and C. Braatz (A.S.H.V.E. Transactions Vol. 34,1928, p. 547). No. 909--Air Infiltration Through Double-Hung Wood Win dows, 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). * 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). 4 The Infiltration Problem of Multiple Entrances, by A. M. Simpson and K. B. Atkinson (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning, June, 1936, p. 345). Infiltration Characteristics of Entrance Doors, by A. M. Simp son (Refrigerating Engineering, June, 1936). * 8 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. BLacksh&w and Carl 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, Heating, 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). Vol6.N32e,u1t9r2a6l ,Zpo.n5e9)i.n Ventilation, by J. E. Emswiler (A.S.H, .VJ3. Transactions, \ CHAPTER 9 NATURAL VENTILATION Wind Forces, Temperature Difference Forces, Heat Removal, Effect of Unequal Openings, Combined Wind and Temperature Forces, Types of Openings, Windows, Doors, Skylights, Roof. Ventilators, Principles of Control, Stacks, 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 (b) 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 location. The'ventilating results obtained will vary, from time to time, due to varia tion 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: (1) 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 3, Chapter 15 for the average wind velocities for the months June to September in various, localities throughout 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 direc tion 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 considerably above 5 mph. There are relatively few places where the velocity falls below one- half of the average for many horns per month. Consequently, 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 = effer.tiveDess of npeniugs. ( should be taken at 0.S0 to 0.60 for perpendicu lar winds and 0.25 to 0.35 for diagonal winds1.) 169