Document vxVJ6qEgnogbLdL6gLJD20Bm

446 CHAPTER 24 . 1965 Guide Arid:Data:Book Tabie 16.... Determination, ofi:U..Value, Resulting from. Addition of Insulation to Uninsulated Building *. Sections (Concluded) r-.; : ; (For m itt Tobits ISA and 198) PARTE HAT ROOFS AND CE1UNGS*WITH ROOF DECK -' U Vafaa of Roof viSwel Roof Bed; hmrfaOoo* _ Conductance C of Roof-Oedr fawfatioo 0.12 0.15 0.19 0.24 <X36 0.72 U O' U U U . U ^ -^(Contwid/ronvp.,45`0 . Solutem: From Table 11, for heat Sow down, the U vahte for this ceiling ;G3, without' insulation, ts 0.40. Referring to Table 16, Part D, with the value 0.40 in Column 1, find Ot *"0.101 in Column 4; enter.-Column. 1.at 0.101 and find U, 0.056 in Column 8. Correct for framing (8 in. joists'oni'16 in. centers) from Fig. 4, and find corrected ceiling coefficient U, - 0.059; R, -* 170. , , By interpolation in Table 17, Part B, using 95 F ventilation air and 160 F'sol-air temperatures, the effective attic resistance - ft, is 8Jt. ' "*' The overall coefficient for. the combined ceiling and attic fa: ! , o:io 0.15 . 0.20-' 0.25 . o:3o ; 0.05 .0.06 0.07 0.08 *' O.OS' 0.09 0.08 0.09 0.09 .0.10 0.07.' 0108; 0.10 0.11. o;i2 0.07 0.09 0.11 0.12. 0.13 0.08 0 09 0.11. .0.12 0:13 0.16 0.15- 0.19 9-16 0.21 V. - - * ,, ,1 0.04 S.+ S. 17.0+8.*,' Heat gain - W (I. -<.)> 0.04 X 1000 X (160-75) . . Btuh. . 3400 `* j 1 , . 0.35 0.40 ' 0.50 . 0.60 ,, 0.70 '; 0.09 id.io 0.09 0:11 , .. 0.10 0.12 : ` 0.10 .0.12 0.10 -0.12 6.121 0.13" 0.14, 0.14' 0.15 o.ii 0.15 0.16 0.17,. 0.18; 0.18'. tTm 0.19 0.26 0.21 0.29 0.22 0 33 0.24 0:35 * Interpolation er mQd extmptdatioa may bo tH, BASEMENT FLOOR,' BASEMENT WALL, AND CONCRETE SLAB FLOOR COEFFICIENTS The heat transfer through basement walls and floors to the ground is dependent on: the temperature difference between the air.within,the room and that of the ground, on the ma terial constituting the wall or floor, and on the conductivity Table 17 -- - Effective Resistance of Ventilated Attics*--(Summer Condition)1 PART A. NON-REFLECTIVE SURFACES No yenfSofron .. | Natural Yoatiatioa Power VeatSaiioa* . . VenfifaWen ' Air temp^F Sd-oa^ ttrap,, f - t* 0- -i1;, -- Ventilatten rate, efm/q ft .... at* - OJ | - 1.0 1 .. 80 .90 r;'loci,^ -i ( s LC..; :: ;; : K:::: p: , tp-i loo . : ! n. ' 1/U Ceiling redsfance. nri . , . . 10 "20 10 20 10 20 * 10 20 10 20 120 . 140 v-1.9-: 1.9 1.9 1.9 1.9 .8.8 , ..8 8.4 8.6 ..8.6 . 9.8 6.6 6.7 '9.3 10 If 9.6 10. 16 18 11 . . "to IS " S 120 140 ,i2o . . i40" ;` 160 , 1.9 1.9 ; i.9 . 1.9 J.9 1.9' 1.9 i:9 . 1.9 ; .1.9 .6 .9 .7 .8 ,8.1 8.4 4-6 6. 6.8 6.7 7.9 .9.0 9.1 7.6 . 8.6 - '. .4 .6 "'...8 1, 8.8 V`4.4. ..7 " " 48. ,',8.1 ' . ...S. 6.0 . 7.9 \4.0. 5.8 7. 10 6.9 13 14: . ' 9.6. 1 .8.7 11 r 10 41 6.6 8.3 17 . . 6.9 10 13 . PART B.. REFLECTIVE SURFACES' . - -r , ; -, , , . 120:, :r. '. i4o .. -120'] 140 . - 9.5 9.5 6.5; : '4'.6 9.6' -6.6. . 9.6 . ,9.6 TT6.6. :\6\6, :; 9.6 81 . 8.8 ; ''18 :. 8.f ` ' 9.0 ,.14 " 8.8. 9. '15 , i7 * 18 18 7.6 7.7 " 7`9 8.0 * ' 10 .is : 8.8 ;.i 16 8.8 , \18 ` \ 16 -! .17 18 19 is 14 ' , 16 ` 5 7 17 19 ' 1 \ 13 18 SO ' S ' 19 ( 6 ( o 120 , .. f- ;; 140; - .. 9.6 . ..9.6 6.6' 9.6 . 6.6 7.0 7.8 7.9 7..4 ( 8.0; 10 . 7,8 K 10 . 1 , 8. ,11 - 14 * 8.6. . 11 is IS 18 - 8.8 16 IS SO - intennusfM rtsmanct u asea woen there ie nttfoYentiletian. A ratue for no VestiUtiaa t* also included. The effective rechtiace of tbe eitie may be added to the rtasstaae* (i/U) d Ibe ceiling.(TxbU 14..Pert D) to obtaia the effective remst&nc* et the combination beeed oo eot-eir (Chapter27) sad room temperature- Ttoe ratamappiy to wvdd fame oonetriiction-with a roof deefc end roofing bavins * oQnducUooo of 1.0 Btn/(xi ft) (hr) (K deg). ' uX.Wbcn vcntiistioa meets the reqmiecoesta of Table 8 in Chapter 23,- 0J efa/aq ft' may. be emumed aa the' natural eammer rantflatiaa rate'for Aetata P^?j5itfasee'Dm*t, abbreviatedreUooe (hr) (eqTt) (Pdeg) per Btu.'Determine eeiQnj;resiataneefromTables 11 aad 10. and correct for framing by FIs- 4. Do not add.the effect of a reflective wrtace lacing the attic, to the ecuing reusUsce from TatJe 10, Part D, aa it is aeeounted for in Table 17, Part B. / ' r-.-i. Reef niface temperature rather than eol-air temperature'(eee Chapter 27)'may be uaed if 0.26 is subtracted from the attic resiatanoe shown 1 :- Bated on air diSsoarpng outward from attic. - v : .u * Sorfaoea with tSretire emissivity E of 0.03 between joists facias the attic space. - .1 Design'Heat Transmission Coeffidente 0{ the surrounding earth- The conductivity of the earth will v&ry ^th local conditions, and ia usually unknown. Tests* at tbe ASHRAE Research Laboratory indicate a heat flow of approximately 2.0 Btu per (hr) (sq ft) through an uninsulated ooocrete basement floor, with a temperature difference of 20 deg between, basement floor and the air temperature 6 in. above the floor. The TJ value of 0.10 is sometimes used for concrete basement floors on ground. For more recent proced ures', see National Bureau of Standards Report BMS-103. For basement walls below grade only, the temperature dif ference for winter design conditions will be greater than for the floor. The test results indicate a unit area heat loss, at midheight of the basement wall portion below grade, of approxi- giately twice that of the same floor area. For concrete'slab floors laid in contact with the ground at grade level, tests7 indicate that, for smallfloor areas (equal to that of a house 25 feet square), the heat loss may be calculated as proportional to the length of exposed edge rather than total area. This amounts to 0.81 Btu per (hr) (linear foot of ex posed edge) (Fahrenheit degree difference between the indoor air temperature and the average outdoor air temperature). It should be noted that this may be appreciably reduced by in sulating under the ground slab and along the edges between the floor and the abutting walls. See also sections on Basement Temperatures and Heat Loss, and Floor Heat Loss in Base"*Houses, in Chapter 26. In most calculations, if the 447 Table 18.... Coefficients of Transmission (U) of Windows, Skylights, and Light -Transmitting Partitions - " Btu per (M'ltq Hi (f 6eg) -t * PART A--VERTICAL PANELS UXTEtUQR WINDOWS AND PARTtTiONSY-- FIAT GLASS, GLASS SLOCK. AND FLASTK SHEET . ; , - . Decrip5on .. Exterior*" Interior Winter S-maar Flat Glass ^ single'glass, t ,. , 1.13 1.08 0.73'" insulating glass--double* - ... ^ in. air space ' J in. air space ! i in. air apace' - - 1 insulating gLase^-triple^ i in. air spaces ., r" f* ` 1 in. air spaces - . storm windows ;. " ' ,!1 in.--4 in. air space ; 0.69. 0:65 . 0.58' 0.64 ` 0.61 0.56 0.51 '0.49 0.46 ' 0.47 1 0:45 .0-36 .'035 0:56 0.54 ,0.38" " 0.30 , .0:44-. Glass'Block* 6 X 6 X 4 in.' thick' ' ` ' 0.60 -'6:57 8 X 8 X 4 in. thick 0.56 ' 0.54 --with cavity divider 0.48 0.46 12 X 12 X 4 in- thick 0-52 0.50 .--with cavity. divider u., - *j`., 5-0.44.-' !`.0.`42*> 12`X 12 X 2 in. thick '"0.60 0-57* 0146 0.44 0.38 0.41 0.36 0.46 .Single Plastic Sheet .. 1.09 ,.1.00; .0.70. GLASS AND DOOR COEFFICIENTS The U values given in Table 18 for flat glass, glass block, and plastic-panels were obtained from ASHRAE Research Reports in cases where the panels have been tested. In other instances values were computed using procedures outlined earlier in this chapter. Values in Table 19 for doors were cal culated. For winter conditions an outdoor surface conductance of 6.0 Btu per (hr) (sq ft) (F deg) was used and. for summer conditions 4.0 Btu per (hr) (sq ft) (F deg). The indoorsurface conductance was taken as 1.46 Btu per (hr) (sq ft) (F deg) for ' vertical surfaces, 1.63 for horizontal surfaces with heat flow up, and 1.08 for horizontal surfaces with heat flow down. The outdoor thermal'conductances are for wind velocities of 15 and 7$ mph, respectively. Adjustments for other wind ve locities may be made using'factors in Table 20. . All values' should be considered approximate, since some parameters which may have important effects were not considered. For example, in an actual installation the indoor surface of a glazing panel may be exposed to nearby radiating surfaces such as radiant-heating panels or exposed windows in adjacent or opposite walls having much higher or lower temperature'than the indoor air. Use of the' listed U value assumes that the surface temperature of surrounding bodies is equal to the ambient air temperature. Air movement across the indoor surface of a panel, such as caused by outlet grilles in the sill, will increase the U value.. Shading devices such as Venetian blinds, draperies, and roller shades will reduce the V value substantially if they.fit tight to the window jambs, head, and sill and are made of a non-porous .material. As a rough approximation tight-fitting shading devices may be considered to reduce the U value' of vertical exterior single glaring by 25 percent, and of vertical exterior double glazing and glass block by 15 percent. These adjustments' should not be. considered in choosing heating equipment, but may be used for calculating Htveign cooling loads. FART 6--HOIUZONTAI'PANELS (SXYUGHTS)--FLAT GLASS, GLASS filOCK, AND FLASrtC BUBBlfS ' Description Exterior*.Winter4 Summer* Interior4 Flat Glass single glass . - insulating glass--doubleh-- in. air space _i in. air apace | in. air space 1.22 0.83 0.96 0.75 0.70 ; 0.66. 0.49 . 0.46 0.44' 0.62 0.59 0.56 Glass Block* , . 11 X 11 X 3 in. thick with,.. ,, ......... cavity divider 12 X 12 X 4 in, thick with cavity divider ` 0.53 , 0.61.: `o'.35;: 0-.34;. 0.44 0.42 Plastic Bubbles' single wailed double walled , . . ` v 1.15 - 0.80. 0.-70 ; 0.46 PMT C-ADSUSTMENT FACTORS FOR VARIOUS WINDOW* TYPES (MULTIPLY u VALUES IN FARfS A AND 0 BY THS FACTORS) Window Description ^ Single Gian Double or Storm Triple Windows v Glen AU Glass* Wood Sash--80% Glass Wood Sash--60% Glass, . Metal Sash--80% Glass 1.00. . .1.00 0.90 *0.95 0.80 0.85 - 1.00 1.20 1.00 0.90 0.80 1.20* * Sa Part C for adjustment for nria b Double end triple refer to the number ot Uehta of slue. 4 For beat flow, opi v *= - - - ' * Foe beet flow down..,- . ,\> f Baaed on area of opeainc. not total eurfeee e ' to eriadove with neeUaibte opnqoe *r