Document 85GaVGxEEMwY63ERngKLbXmRo

HEATING VENTILATING AIR CONDITIONING CUIDE 1944 Table 5. Coefficients of Transmission (U) of Frame Walls with Insulation Between Framing3' ^ Coefficients are expressed in Bin per hour Per square foot per degree Fahrenheit difference in temperature between the air on the two sides, and are based on a wind velocity of 16 mph. COEFFICIENT WITH NO ' INSULATION FRAMING 0.11 0.12 0.13 0.14 0.15 COEFFICIENT WITH INSULATION BETWEEN FRAMING Blanket ob Bat Insulation between Framing ('Itnekuess below) 1 IN. 2 IN. 3 IN. ABC 0.078 0.083 0.088 0.092 0.097 0.064 0.067 0.070 0,073 0.075 0.055 0.057 0.059 .0.061 0.062 in. Loose Mineral Wool - between Framing a a > D 0.051 0.054 0.056 0.058 0.059 33 34 35 36 37 0.16 0.10 0.17 0.10 0.18 o.n 0.19 0.11 0.20 0.12 0.077 0.080 0.082 0.084 0.087 0.065 0.066 0.068 0.069 0.070 0.060 0.062 0.063 0.064 0.066 38 39 40 41 42 0.21 0.12 0-22 0.12 0.23 0.12 0.24 0.12 0.25 0.13 0.088 oim 0.093 0.094 0.095 0.072 0.073 0.074 0.076 0.076 0.067 0.069 0.069 0.070 0.072 43 44 45 46 47 OQOOO 0.13 0.14 0.14 0.14 0.14 0.096 0.097 0.098 0.10 0.10 0.077 0.078 0.078 0.080 o.oso 0.072 0.073 0.073 0.075 0.075 43 49 60 51 52 0.31 0.32 0.33 0.34 0.35 0.14 0.10 0.15 0.10 0.15 0.11 0.15 . 0.11 0.15 0.11 0.082 0.032 0.083 0.083 0.085 0.076 0.076 0.077 0.078 0.078 53 54 55 58 57 0.36 0.16 0.37 0.16 0.38 0.16 0.39 0.16 0.40 0.16 0.11 0.11 0.11 0.11 0.11 0.085 0.087 0.087 0.087 0.088 0.079 0.080 0.080 0.081 0.082 58 59 60 61 62 0.41 0.16 0.42 0.16 0.43 0.170.44 0.17 0.11 0.11 0.11 0.12 0.088 0.088 0.090 0.090 0.082 0.082 0.083 0.083 63 64 65 66 i4iuie may oe usea for determining the coefficients of transmission of frame constructions with' the types and thicknesses'of insulation indicated in Columns A to D inclusive between framing.' Columns A, B and C may be used for walls, ceilings or roofs with only one air space between framing but are not applicable to riflings with no flooring above. (See Table 10.) Column D is applicable to walls only. Example: Find the coefficient of transmission of a frame wall consisting of wood siding, H6 in. insulating board sheathing, studs, gypsum lath and plaster, with 2 in. blanket insulation between studs. -According to Table 4, a wall of this construction with no insulation between studs has a coefficient of 0.19 (Wall No. 4D). Referring to Column B above, it will be found that a wall of this value with 2 in. blanket insulation between the studs has a coefficient of 0.084. ^Coefficients corrected for 2x4 framing. 16 in. o. c. 'Based on one air space between framing. 102 CHAPTER 4. HEAT TRANSMISSION COEFFICIENTS to those shown in Example 1, using fundamental Formulas 1, 2 and 3. and the values of k (or C),fufa and a in Table 3. Actual thicknesses of lumber are used in the computations rather than nominal thicknesses. The computations for wood shingle roofs applied over wood stripping are based on 1 by 4 in. wood strips, spaced 2 in. apart. Since no reliable figures are available concerning the conductivity of Spanish and French clay roofing tile, of which there are many varieties, the figures for such types of roofs were taken the same as for slate roofs, as it is probable that the values of U for these two types of roofs will compare favorably. The thicknesses upon which the coefficients in Tables 4 to 17 inclusive, are based are: Brick veneer....... .............................. 4 in Plaster and metal lath.................... M in Plaster (on wood lath, gypsum lath or insulating board) .______ in Slate (roofing)......... ...------------ <n Stucco on wire mesh reinforcing.-- 1 in Tar and gravel or slag-surfaced built-up roofing.....;_______ ____ M in 1-in. lumber (S-2-S)_________ ____ % in. 1 )4-m. lumber (S-2-S)___________ ljfe in. 2-in. lumber (S-2-S)~~ 1% in. 2J4-in. lumber (S-2-S) 2)4s in. 3-in. lumber (S-2-S)_____________ 2% in. 4-in. lumber (S-2-S) 3% in. Finish flooring (maple or oak)____% in. Solid brick walls are based on 4 in. hard brick (high density) and Uie remainder common brick (low density). Stucco is assumed to be 1 in, thick on masonry walls. Where metal lath and plaster are specified, the metal lath is neglected. The coefficients of transmission of the pitched roofs in Table 15 apply where the roof is over a heated attic or top floor so the heat passes directly through the roof structure including whatever finish is applied to the underside of the roof rafters. Coefficients for frame construction were corrected for the effect of the framing where such correction would increase the coefficients, but . not where the correction would decrease the coefficient7. In the latter case, the correction is generally small and the uncorrected coefficient is on the side of safety. Although theoretical coefficients below 0.10 are included in the tables, a minimum coefficient of 0.10 is generally recommended to allow for possible defects in workmanship, poor construction and other factors which would increase the heat loss. The lower the theoretical wall or roof coefficient the greater will be the percentage of error due toconstruction defects or failure of the insulation to' perform as rated. Combined Coefficients of Transmission If the attic is unheated, the roof structure and ceiling of the top floor must both be taken into consideration, and the combined coefficient of transmission determined. The formula for calculating- the combined coefficient of transmission of a top floor ceiling, unheated attic space, and pitched roof per square foot of ceiling area is: Hr X (4) 'Effect of Studs and Joists on Heat Flow Through Frame Walls and Ceilings, by Paul D. Close (Heating, Piping and Air Conditioning, October, 1943, p. 529).