Document ZJyyNa36D1B2Gez7j5Yjxwb97

140 CHAPTER 6 1946 Guide and from kitchens during lengthy periods of cooking, elimination of ; .sources of vapor such as urivented gas stoves, or by local application of heat or insulation to raise surface temperatures. . Interstitial condensation results from vapor transmission which is dependent on vapor pressure differential and the ratio of the rate at which vapor may enter the materials of the structure to that at which it passes out of the structure. The proper installation of a vapor barrier on the warm side of the structure, where the higher vapor pressure usually exists, will reduce greatly the amount of vapor entering the building construction and will minimize the possibility of objectionable condensation. Such a barrier may consist of a coated paper applied Fig. 4. Permissible Relative Humidities for Various Transmission Coefficients under the plaster, a coated plaster base, or a.vaporTresistant finish applied to the interior wall surface 12. A vapor b'arrier is tentatively defined as a material having a water vapor permeability noj: exceeding 1.25 grains per (hour) (square foot) (inch, of Hg vapor pressure differential). To prevent condensation on the under side of roofs above attic spaces over insulated ceilings, ventilation with outside air may be provided through suitable louvers or other roof ventilators. REFERENCES ' '"Standard Method of Test for Thermal.Conductivity by Means of the Guarded Hot Plate, sponsored by A.S.H.V.E., A.S.T.M., A.S.R.E.,and N.R.C. and approved as a Tentative Code by A.S.H:V.E. and AJS.T.M. in 1942 (AS.T.M. designation C-1-77-42T).. .2--Keat Transmission Through Building Materials, by F..B. Rowley and A; B. Algren (University of" Minnesota, Engineering Experiment Station Bulletin No. 8, p. 11). Radiation and Convection from Surfaces in Various Positions, by G. B. Wilkes and C. M. F. Peterson ' (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513). `' Heat* Transmission Coefficients of Building Materials 141 4--Radiation Corrections for Basic Constanta Used in the Design of All Types of Heating Systems, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Journal Section, Healing.-Piping and Air Conditioning. December 1944, p. 705).' - ` s--Radiation and Convectidn Across Air Spaces in Frame Construction, by G. B. Wilkes and C, M. F. Peterson (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 351). ' Thermal Test Coefficients of Aluminum Insulation for Buildings, by G. B. Wilkes, F. G. Hechter and E.R. Queer (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 109). 7--Effect of Studs and Joists on Heat Flow Through Frame Walls and Ceilings, by Paul D. Close (Heat- ing. Piping and Air Conditioning. October, 1943, p. 529). --A.S.H.V.E. Research Report No. 1213--Heat Loss Through Basement Walls and Floort,-by F. C. Houghten. S. I. Taimuty. Carl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48. 1942. p. 369). 9--Measurements of Heat Losses from Slab Floors, by R. S. Dill, Wm. C. Robinson and H. E. Robinson {National Bureau of Standards, Building Materials and Structures Report BMS 103). l o--Methods of Moisture Control and Their Application to Building Construction, by F. B. Rowley, ` A. B. Algren and C. E. Lund (University of Minnesota Engineering Experiment_Slation Bulletin No.-17>. Moisture Migration: A Survey of Theory and Existing Knowledge, by P. F. McDermott (Refrigerat ing Engineering, August 1941,.p. 103). "--Permissible'Relative Humidities in Humidified Buildings, by Paul D. Close (A.S.H.V.E. Journal Section. Heating. Piping and Air Conditioning, December, 1939, p. 766). > is--Condensation Within Walls, by F. B. Rowley, A. B. Algren and C. E. Lund (A.S.H.V.E. Trans actions, Vol. 44, 1938, p. 95). BIBLIOGRAPHY f A;S.H.V.E. Research Reports: No. 852--Effects of Air Velocities'on Surface Coefficients, by F, B. Rowley, A. B. Algren and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 123). No. 895--Wind Velocity Gradients Near a Surface and Their Effect on Filnj Con-. ductance, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 301). No. 914--Surface Coefficients as Affected by Direction of Wind, by F. B. Rowley and W. A. Eckley (A.S.H.V.E, Transactions, Vol. 38, 1932, p. 33). No. 915--Conductivity of Concrete, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 47). No. 964--The Heat Conductivity of Wood at .Climatic Temperature Differences, by F. B. Rowley (A.S.H.V.E. Transactions, Vol. 39, 1933; p. 329). No. 996--Insulating Value of Bright Metallic Surfaces, by F. B. Rowley (A.S.H.V.E: Transactions, Vol. 40, 1934, p. 413). No. 1026--Thermal Properties of Concrete Construction, by F. B. Rowley, A. B. Algren and Clifford Carlson (A.S.H.V.E. Transactions, Vol. 42, 1936, p. 33). No. 1048--Thermal Properties of Concrete Construction, by F. B. Rowley, A. B. Algren and Robert Lander (A.S.H.V.E. Transactions, Vol. 43, 1937, P- 33). /insulating Effect of Successive Air Spaces Bounded by Bright Metallic Surfaces, by L. W. Schad (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 285). Condensation of Moisture and Its Relation to Building Construction and Operation, by F. B. Rowley, A. B. Algren and C. E. Lund (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 231). A Theory Covering the Transfer of Vapor Through Materials, by F. B. Rowley (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 545). Thermal Conductivity of Wood, by J. D. MacLean (A.S.H.V.E. Transactions, ; Vol. 47, 1941, p. 323). The Specific Heat of Thermal Insulating Materials, by G. B. Wilkes and C. O. Wood (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 493).