Document bgKbGxQ1JamRj5agzYq2LqBk

Heating Ventilating Air Conditioning Guide 1939 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^ 3.3 8.2 14.0 20.2 27.2 34.6 Around frame in masonry wall--calkedb___ 0.5 1.5 2.6 3.8 4.8 5.8 ~ Around frame in wood frame constructjonb_ 2.2 6.2 10.8 Double-Hung Wood Sash Total for average window, non-weatherstripped, Hs-in. crack and &-in. clearance.c Windows Includes wood frame Ipmkftgpa . _ _ 6.6 21.4 39.3 (Unlocked) Ditto, weatheretrippedd 4.3 15.5 23.6 16.6 59.3 35.5 23.0 80.0 48.6 30.3 103.7 63.4 Total for poorly fitted window, non-weather- atrippea, !-m. crack and Hr*in- clearance.* Includes wonH frame lenlmged 26.9 69.0 110.5 153.9 199.2 249.4 Ditto, weatheratrippedd 5.9 18.9 34.1 51.4 70.5 91.5 Double-Hung Non-weatherstripped, locked Metal Non-weatherstripped, tmlnclfd .............. Windowsf Weatheratripped, unlocked 20 45 20 47 6 19 70 74 32 96 125 154 104 137 170 46 60 76 Industrial pivoted, Hi-in. cracks 52 108 176 244 304 372 Rolled Section Steel Sash Windows^ Architectural projected, Hrin. crackb_____ Architectural projected, Hi-in. crackb_____ Residential casement, Hi-in. crack! Residential casement, Hrin- crack! Heavy casement section, projected, Hj-in. 15 20 6 14 3 36 52 18 32 10 62 88 33 52 18 86 112 139 116 152 182 47 60 74 76 100 128 26 '36 48 Heavy casement section, projected Hrin. cmrlrl 8 24 38 54 72 92 Hollow Metal, vertically pivoted windowt____ 30 88 145 186 221 242 The values given in this table, with the exception of those for double-hung and hollow metal windows, are 20 per cent less than test values to allow for building up of pressure in rooms, and are based on test data reported in the papers listed at the end of this chapter. bThe 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 walls originates in the brick wall itself and cannot be prevented 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 determined by the calked and not-calked tests. cThe fit of the average double-hung wood window was determined as }-in. crack and $-in. clearance by measurements on approximately 600 windows under heating season conditions. dThe values given are the totals for the window opening per foot of sash perimeter and include frame leakage and so-called elsewhere leakage. The frame leakage values included are for wood frame construction but apply as well to masonry construction assuming a 50 per cent efficiency of frame calking. A !frin. crack and clearance represents a poorly fitted window, much poorer than average. (Windows tested in place in building. ^Industrial pivoted window generally used in industrial buildings. Ventilators horizontally pivoted at center or slightly above, lower part swinging out. ^Architectural projected made of same sections as industrial pivoted except that outside framing member 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. !-in. crack is obtainable in the best practice of manufacture and installation, &-in. crack considered to represent average practice. iOf same design and section shapes as so-called heavy section casement but of lighter weight, Hrin. crack is obtainable in the best practice of manufacture and installation, Hrin. crack considered to represent average practice. jMade of heavy sections. Ventilators swing in or out and stay set at any degree of opening. Hrin. crack is obtainable in the best practice of manufacture and installation, crack considered to represent average practice. kWith reasonable care in installation, leakage at contacts where windows are attached to steel frame work and at mullions is negligible. With Hj-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. 124 Chapter 6. Air Leakage DOOR LEAKAGE vary greatly in fit because of their large size and tendency to DOIFor a well fitted door, the leakage values for a poorly fitted double- window may be used. If poorly fitted, twice this figure should hung w ^ weat|,erstripped, the values may be reduced one-half. A *1 door which is frequently opened, such as might be found in a store, ^ id have a value applied which is three times that for a well fitted hou 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 oddest and windiest weather The infiltration rate through swinging and revolving doors is generally matter of judgment by the engineer making cooling load determinations and in the absence of adequate research data the values given in Table 3 reoresent current engineering practice. These values are based on the average number of persons in a room at a specified time, which may also be the same occupancy assumed for determining the outside ventilation requirements outlined in Chapters 3 and 8. Table 3. Infiltration Through Outside Doors for Cooling Loads3 Expressed in Cubic Feet per Minute per Person in Room Application Pair 36 in. Swinging Doobs, Single ' ENTBANCBb 7.5 4.5 7.0 6.0 25.0 8.0 2.5 7.0 2.5 3.5 5.0 3.5 3.0 2.0 2.5 2.5 3.5 For doors located in only one wall or where doors in other walls are of revolving type, bVestibules with double pair swinging doors, infiltration may be assumed 75 per cent of swinging door values. Infiltration for 72 in. revolving doors may be assumed 60 per cent of swinging door values. SELECTION OF WIND VELOCITY Although all authorities do not agree upon the value of the wind veloc ity that should be chosen for any given locality, it is common engineering practice to use the average wind velocity during the three coldest months of the year. Until this point is definitely established the practice of using average values will be followed. Average wind velocities for the months, of December, January and February for various cities in the United States and Canada are given in Table 2, Chapter 7. 125