Document 93LvgMOMpmbjg4ny7J8178QZD

216 CHAPTER 10 1951 Guide Table 2. Infiltration Through Windows Expressed in Cubic Feet per Foot of Crack per Hour* Type of Window Remarks Wind Velocity, Miles peb Hour 5 10 15 20 25 30 Around frame in masonry wall--not calked**......... 3 8 14 20 27 35 Around frame in masonry wall--calked". ........... 1 2 3456 Around frame in wood frame construction0 .......... 2 6 11 17 23 30 Total for average window, non-weather-etripped, Double-Hung Wood A-in. crack and Aiin- clearance.0 Includes Sash Windows (Un wood frame leakage".............................................. locked) Ditto, weatherstripped*.............................................. Total for poorly "irdnw non-weather- 7 4 21 13 39 59 80 104 24 36 49 63 stripped, A-in. crack and A-in. clearance.** Includes wood frame leakage*................................ 27 69 111 154 199 249 Ditto, weatherstripped*.............................................. 6 19 34 51 71 92 Non-weatherstripped, locked..................................... 20 Non-weatherstripped, unlocked................................ 20 Weatherstripped, unlocked......................................... 6 45 47 19 70 96 125 154 74 104 137 170 32 46 60 76 Industrial pivoted, A-in. crack*-- ...................... 52 108 176 244 304 372 Architectural projected, A-in- crack ...................... 15 36 62 86 112 139 Rolled Section Steel 20 52 88 116 152 182 6 18 33 47 60 74 Sash Windows k Residential casement, A-in. crack4......................... 14 32 52 76 100 128 Heavy casement section, projected, A-in* crack1.. 3 10 IB 26 .36 48 Heavy casement section, projected A-in. crack1... 8 24 38 54 72 92 Hollow Hetal, vertically pivoted window*..................................................... 30 88 145, 186 221 .242 * The values given in thu table, with the exception of those for double-hung and hollow metal windows, are 20 peroent less than test values to allow for building up of pressure in rooms, and are based on test data reported in the papers listed in chapter footnotes. b The values given for frame leakage are per foot of sash perimeter, as determined for double-hung wood windows. Some of the frame leakage in masonry wails originates in the brick wall itself, and cannot be pre vented by calking. For the additional reason that calking is not done perfectly and deteriorates with time, it is considered advisable to choose the masonry frame leakage-values for calked frames as the average deter mined by the calked and non-ealked testa. c fit, 0f the average double-hung wood window was determined as 16-in. crack and A-in. clearance by measurements on approximately .600 windows under heating season conditions. d The values given are the totals for the window opening per foot of sash perimeter, and include frame mid socaSed elsewhere leakage. The frame leakage values included are for wood frame construction, but apply as well to masonry construction assuming a 50 peroent efficiency of frame calking. e A A-in. crack and clearance represent a poorly fitted window, much poorer than average. (Windows tested in place in building, so that no reduction from test values is necessary, as mentioiled in footnote a. . s Industrial pivoted window generally used in industrial buildings. Ventilators horizontally pivoted at center or slightly above, lower part swinging out. h Architecturally projected made of rama sections as industrial pivoted, except that outside framing mem ber is heavier, and it has refinements in weathering and hardware. Used in semi-monumental buildings such as schools. Ventilators swing in or out and are balanced on side arms. A-in. crack is obtainable in the best practice of manufacture and installation. A-hi. crack considered to represent average practice. l Of Barn- dftftig" nnf* section shapes as so-called heavy section easement, but of lighter weight. A-in. crack is obtainable in the' beet practice of manufacture and installation', A-in. crack considered to represent average practice. i Matte of heavy sections. Ventilators swing in or out and stay set at any degree of opening. A-in. crack b obtainable in the best practice of manufacture and installation, A-in. crack considered to represent average practice. k reasonable care in installation, leakago at contacts where windows are attached to steel frame work and at mullions, is negligible. With A-in. crack, representing poor installation, leakage at contact with steel framework is about one-third, and at mullions, about one-sixth of that given for industrial pivoted windows in the table. * poorly fitted window. All of the figures for double-hung wood windows are for the unlocked condition. Just how a window is closed, or fits when it is closed, has considerable influence on the leakage. The leakage will be high if the sash are short, if the meeting rail members are warped, or if the frame and sash are not fitted squarely to each other. It is possible to have a window with approximately the average crack and clearance that will have a leakage at least double that of the figures shown. Values for the average double-hung wood window in Table 2 are considered to be easily obtainable figures, provided the workmanship on the window is good. Should it be infiltration and Ventilation 217 known that the windows under consideration are poorly fitted, the larger leakage values should be used. Looking a window generally decreases its leakage, but in some cases may push the meeting rail members apart and increase the leakage. On windows with large clearances, locking will usually reduce the leakage. Wood casement windows may be assumed to have the same unit leakage as for the average double-hung wood window when properly fitted. Lock ing, a normal operation in the closing of this type of window,- maintains the crack at a low value. For metal pivoted sash, the length of crack is the total perimeter of the movable or ventilating sections. Frame leakage on steel windows may be neglected when they are properly grouted with cement mortar into brick work or concrete. When they are not properly sealed, the linear feet of Table 3. Infiltration Through 72-Inch Revolving Door and 36-Inch Swing ing DoOR*-b (Cubic Feet per Person per Passage) USAGE FREELY-REVOLVING DOOR DOOR EQUIPPED WITH BRARH 75 60 60 50 40 40 36-Inch Swinging Door.......................................................... 100 * Them figures are baaed on the assumption that there ia no wind pressure and that swinging doors are in use in one wall only. Any swinging doors in other walls should be kept closed to insure air conditioning in accordance with these reoommended standards. b From Application Engineering Standards for Air Conditioning for Comfort 1947, Air Conditioning A Refrigerating Machinery Association, Inc., Washington, D. C. Used by permission. sash section in contact with steel work at mullions should be figured at 25 percent of the values given in Table 2 for industrial pivoted windows. When storm sash are applied to well fitted windows, some reduction in infiltration is secured; the application of the sash provides an air space which reduces the heat transmission and helps prevent the frosting of the win-. dows.s By applying storm sash to poorly fitted windowB, a reduction in leakage of 50 percent may be obtained, the effect, so far as air leakage is concerned, being roughly equivalent to that obtained by the installation of weatherstrips. Door Leakage Doors vary greatly in fit because of their large size and tendency to warp. . For a well fitted door, the leakage values for a poorly fitted double-hung wood window may be used; If poorly fitted, twice this figure should be used. If weatherstripped, the values may be reduced one-half. A single door which is frequently opened, as might be the case in a store, should have a value applied which is three times that for a well fitted door. This extra allowance is for opening and closing losses, and is kept from being greater by the fact that doors are not used as much in the coldest and windi est weather. The infiltration rate through swinging and revolving doors is generally a matter of judgment by the engineer making cooling load determinations, and in the absence of adequate research data, the values given in Table 3