U value (Transmittance) = 1/Ra-a
Ra-a = Rso + R1 + R2 + R.. + Rsi
R material = b/λ
keterangan:
b = thickness (m)
λ = conductivity (W/mK) (transmisi heat tidak dipengaruhi ketebalan material)
Ra-a = air-to-air resistance
Rso = outer surface resistance
Rsi = indoor surface resistance
R1+R2+R.. = total resistance of all materials
| THERMAL PROPERTIES OF SURFACES AND CAVITIES | ||||
| absorptance & emittance | reflectance | absorptance & emittance | ||
| brick | white, glazed | 0,25 | 0,75 | 0,95 |
| light colours | 0,40 | 0,60 | 0,90 | |
| dark colours | 0,80 | 0,20 | 0,90 | |
| roofs | asphalt or bitumen | 0,90 | 0,10 | 0,96 |
| red tiles | 0,65 | 0,35 | 0,85 | |
| white tiles | 0,40 | 0,60 | 0,50 | |
| aluminium (oxidised) | 0,20 | 0,80 | 0,11 | |
| paint | white | 0,30 | 0,70 | 0,95 |
| matt black | 0,96 | 0,04 | 0,96 | |
| weathered building surfaces: light | 0,50 | 0,50 | 0,60 | |
| medium | 0,80 | 0,20 | 0,95 | |
| SURFACE RESISTANCES (m2 K/W) | normal surfaces | high emittance surfaces | ||
| inside, | walls | 0,12 | 0,30 | |
| ceiling, floor: | heat flow up | 0,10 | 0,22 | |
| heat flow down | 0,14 | 0,55 | ||
| outside, | walls, | sheltered | 0,08 | 0,11 |
| normal exposure | 0,06 | 0,07 | ||
| severe exposure | 0,03 | 0,03 | ||
| roofs, | sheltered | 0,07 | 0,09 | |
| normal exposure | 0,04 | 0,05 | ||
| severe exposure | 0,02 | 0,02 | ||
| CAVITY RESISTANCES (m2 K/W) | normal surfaces | high emittance surfaces | ||
| unventilated: | ||||
| 5 mm cavity, | any position | 0,10 | 0,18 | |
| >25 mm cavity, | heat flow horizontal | 0,18 | 0,35 | |
| heat flow up | 0,17 | 0,35 | ||
| heat flow down | 0,22 | 1,06 | ||
| multiple foil, | air space one side: | |||
| heat flow horizontal or up | - | 0,62 | ||
| heat flow down | - | 1,76 | ||
| ventilated: | ||||
| fibr.cement ceiling & dark metal roof | 0,16 | 0,30 | ||
| fibr.cement ceiling & fibr.cement roof | 0,14 | 0,25 | ||
| fibr.cement ceiling & tiled roof, sarking | 0,18 | 0,26 | ||
| in ordinary cavity walls | 0,18 | - | ||
| THERMAL PROPERTIES OF BUILDING ELEMENTS: WALLS | ||||||
| note: EPS = expanded polystyrene slab | U-value W/m2K | admittance W/m2K | time-lag hours | decr.factor - | ||
| brick, | single skin, | 105 mm | 3,28 | 4,2 | 2,6 | 0,87 |
| 220 mm | 2,26 | 4,7 | 6,1 | 0,54 | ||
| 335 mm | 1,73 | 4,7 | 9,4 | 0,29 | ||
| brick, | single skin, | 105 mm palstered | 3,02 | 4,1 | 3 | 0,83 |
| 220 mm plastered | 2,14 | 4,5 | 6,5 | 0,49 | ||
| 335 mm plastered | 1,79 | 4,5 | 9,9 | 0,26 | ||
| brick, | cavity, | 270 mm plastered | 1,47 | 4,4 | 7,7 | 0,44 |
| * same with 25 mm EPS in cavity | 0,72 | 4,6 | 8,9 | 0,34 | ||
| * same with 40 mm EPS in cavity | 0,55 | 4,7 | 9,1 | 0,32 | ||
| * same with 50 mm EPS in cavity | 0,47 | 4,7 | 9,2 | 0,31 | ||
| concr.block, solid, 200 mm plasterboard | 1,83 | 2,5 | 6,8 | 0,35 | ||
| * same but foil-backed plasterboard | 1,40 | 1,82 | 7 | 0,32 | ||
| * same + 25 mm EPS (no cavity) | 0,93 | 1,2 | 7,2 | 0,3 | ||
| * same but 25 cav.+ 25 EPS + plasterboard | 0,70 | 1 | 7,3 | 0,29 | ||
| * same but lightweight concrete | 0,68 | 1,3 | 7,4 | 0,46 | ||
| * same but foil-backed plasterboard | 0,61 | 1,5 | 7,7 | 0,42 | ||
| * same + 25 mm EPS (no cavity) | 0,50 | 1,1 | 8,2 | 0,36 | ||
| * same but 25 cav.+ 25 EPS + plasterboard | 0,46 | 1 | 8,3 | 0,34 | ||
| concr.block, hollow, | 100 mm inside plast. | 2,50 | 3,8 | 2,4 | 0,89 | |
| 200 mm inside plast. | 2,42 | 4,1 | 3 | 0,83 | ||
| concrete, dense, cast, 150 mm | 3,48 | 5,3 | 4 | 0,7 | ||
| * same + 50 mm woodwool slab plastered | 1,23 | 1,7 | 6 | 0,5 | ||
| * same but lightweight plaster | 1,15 | 1,7 | 6,3 | 0,49 | ||
| 200 mm | 3,10 | 5,5 | 5,4 | 0,56 | ||
| * same + 50 mm woodwool slab plastered | 1,18 | 2,2 | 7,7 | 0,36 | ||
| * same but lightweight plaster | 1,11 | 1,7 | 7,6 | 0,35 | ||
| concr.precast panel, 75 mm | 4,28 | 4,9 | 1,9 | 0,91 | ||
| * same + 25 cav. + 25 EPS + plasterboard | 0,84 | 1 | 3 | 0,82 | ||
| concr.precast, 75 + 25 EPS + 150 L/W concr. | 0,58 | 2,3 | 8,7 | 0,41 | ||
| * same but 50 mm EPS | 0,41 | 2,4 | 9,2 | 0,35 | ||
| brick veneer, 105 mm, cav. Plasterboard | 1,77 | 2,2 | 3,5 | 0,77 | ||
| * same but foil-backed plasterboard | 1,36 | 1,7 | 3,7 | 0,75 | ||
| * same with 25 mm EPS or glass fibre | 0,78 | 1,1 | 4,1 | 0,71 | ||
| * same with 50 mm EPS or glass fibre | 0,50 | 0,9 | 4,3 | 0,69 | ||
| * same, 25 EPS + foil-backed plasterboard | 0,69 | 1 | 4,1 | 0,71 | ||
| brick veneer, 100 mm, cav. Plasterboard | 1,57 | 2,1 | 4,1 | 0,72 | ||
| * same but foil-backed plasterboard | 1,24 | 1,7 | 4,3 | 0,69 | ||
| * same with 25 mm EPS or glass fibre | 0,74 | 1,1 | 4,7 | 0,65 | ||
| * same with 50 mm EPS or glass fibre | 0,48 | 0,9 | 4,9 | 0,62 | ||
| * same, 25 EPS + foil-backed plasterboard | 0,66 | 1 | 4,7 | 0,64 | ||
| framed, | single fibro or galv.iron | 5,16 | 5,2 | 0 | 1 | |
| * same + cav. + plasterboard | 2,20 | 2,2 | 0,3 | 1 | ||
| * same + 25 mm EPS or glass fibre | 0,86 | 1,1 | 0,5 | 0,99 | ||
| * same + 50 mm EPS or glass fibre | 0,53 | 0,9 | 0,7 | 0,99 | ||
| framed, | 20 mm timber boarding | 3,00 | 3 | 0,4 | 1 | |
| * same + cav. + plasterboard | 1,68 | 1,8 | 0,8 | 0,99 | ||
| * same + 25 mm EPS or glass fibre | 0,76 | 1 | 1 | 0,99 | ||
| * same + 50 mm EPS or glass fibre | 0,49 | 0,9 | 1,2 | 0,98 | ||
| framed, | tile-hang,+paper+cav+50 EPS+plb'd | 0,54 | 0,78 | 1 | 0,99 | |
| * same but 100 EPS or glass fibre | 0,32 | 0,71 | 1 | 0,99 | ||
Keterangan:
Decrement Factor = faktor yang menentukan jumlah fluktuasi temperatur di dalam dibandingkan di
luar (jika nila decr. factor 0.5, maka jika fluktuasi temperatur di luar 20C (siang
ke malam) maka di dalam fluktuasinya hanya 10C)
Sumber : Thermal Design of Buildings, Szokolay
0 comments: