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Effective July 1, 1991 <br />Overview The Chapter 5 Approach allows any combination of building envelope components as long as the <br />collective heat loss doesn't exceed a maximum limit established by code. The calculations on the lower part of this <br />page may be ignored if below grade wall insulation will either be R19 on the Interior or RI exterior, or if the <br />basement will not be a habitable space and unheated, and the floor above is insulated. <br />Page 2, Base Case Dwelling Calculation Compute areas using outer surfaces for walls, ceilings (less skylights), <br />and floors. Use the rough framed opening areas for doors. The glazing area is derived by multiplying a constant <br />value (.15) by the sum of the conditioned floor areas(Don't Include unheated attached garages, etc). <br />Page 2, Proposed Dwelling Calculation Compute areas using outer surfaces for walls, ceilings, and floors. Use the <br />framed <br />units opening r glazing. Since thereChapterboxes st combine <br />the areas of wih the same Uo valuetasinngeentry.WSEC, 0, default values must be used for all <br />walls, ceilings, floors, untested doors/glazing, and to determine below -grade wall/slab UA. <br />The Proposed Dwelling compiys If the the Proposed UA doesn't exceed the Base Case UA. <br />Transfer wall, ceiling, floor, glazing, and door values (Rand U) to the Check list. <br />Method A (below -grade walUslab heat -loss tradeoffs) <br />1. F0veach wall that differs in depth, perform a sr perate calculation using Steps 2 & 3. Sum the totals. 2. Determine wail aria frGr�rtt the slab suriae b t!ie� ttop of the mud iU: Exclude dp0r and glazing areas and insert <br />them into the designated iaoxes below or o;h Base case and Proposed heat of ss. <br />3. Fin the ro rrate wall deptf)s in Table 1 and insert the corre nding wall values into the Base case box(es).` <br />Multiply the corresponding wi I U-value by the area derived in lep #1, <br />4. Meassuure the F,erir0?,tgrdistance in linear feet for each slab under a wall with a diNerent Table 1 depth; lase <br />slab,t_va ue rem ra le 1 corresponding to each wall listed in Stre w U <br />BASE CASE HEATLOSS _I <br />B.G. wall #1 (Ft2) x U _ = Table 1 (Below grade wall/slabs) <br />B.G. slab #1 (L. Ft) x F_ _ <br />Inc rlat d interior wag Values <br />P.C. wall #2 (F12) x U <br />2' depth: walls U.043 <br />B.G. slab #2 (L. Ft) x F__ = slab <br />F.69 <br />depth: walls U.041 <br />TOTAL COLUMN —► slab F,64 <br />µ 7' depth: walls U.037 <br />PROPOSED HEATLOSS slab F.57 <br />Use Chapter 10, page 81, U & F-values for this calculation <br />`U. and the same BASE CASE area/L. ft. measurements. ins rlat rl exteriorW ll i <br />B.G. wall #1 (92) x U_ = 2' depth: walls U.070 <br />B.G. slab #1 slab F.60 <br />(L. Ft) x F_ = 3.5' depth: walls U.064 <br />B.G. wall #2 slab F.57 <br />(Ft2) x U_ = 7' depth: walls U.056 <br />B.G. slab #2 (L. Ft) x F = slab F,42 <br />` uo5: •a+eociout rsr ('Depth' indicates the total concrete above grade <br />wall depth ' <br />Page 1 TOTAL COLUMN including not more than ( of ab <br />