Page 174 - AGC_EN_iBook

174
INSuLatION quaLIty OF tHe eNVeLOPe
The thermal transmittance (U-value) measures the thermal perfor- mance of a building component.The way the U-value is calculated is de ned in standard NBN B 62-002: 2008 (Thermal performance of buildings – calculation of the heat transfer co-ef cient (U value) of building components and elements – Calculation of heat trans- fer coef cients by transmission [hT-value] and by ventilation [hv]) and in standard NBN EN ISO 6946: 2008 (Building components and building elements –Thermal resistance and thermal transmit- tance – Calculation method).
The thermal transmittance of the building elements must not exceed a set maximum U-value.The detailed values are to be found in Annex III of the Belgian EPB legislation.
tHe k-LeVeL
The global level of thermal insulation of a building is given by the K-level.The K-level is calculated on the basis of two factors: which materials are used and at what thickness; and the compactness of the building envelop. Details on how to calculate the K-level are de ned in standard NBN B 62-301: 2008 (Thermal insulation of buildings – K-level – overall thermal insulation of buildings).
Category k-level
Acceptable quality (statutory) 45
Average quality 35
high quality 25
Very high quality 15
table 4. quality levels of thermal insulation The building achieves level k 36. tHe eW LeVeL
The Ew level re ects a building’s characteristic annual primary energy use under standard operating conditions.The calculation method is described in the Walloon Government’s decree of
17 April 2008 (NBN EN ISO 13790: 2008: Energy performance
of buildings – Calculation of energy use for space heating and cooling).
The Ew level takes account of the different energy ows: – the overall thermal insulation;
–The ventilation and the energy use of fans;
– arti cial lighting;
– the production, distribution and losses of the climate control system (heating and cooling);
– energy use for humidi cation;
– energy generated by solar systems.
Windows, curtain walls and other translucent walls:
– Overall value for the curtain wall
– Speci c value for the central glazed part
Doors
Roofs and ceilings
Floors:
– between the inside and the outside air or non-heated adjacent spaces
– between the inside and the ground, crawl space, cellar/basement
table 2. u and R values of the outside walls
major thermal bridges
Facade support pro le – detail A Facade support pro le – detail B simple Facade support pro le – detail B double Facade support pro le – detail D Column (vertical galvanized bolt)
minor thermal bridges
Safety line on the concrete roof (Ø 8 mm) Thermal break at slab -1
Cut for basement access shaft
Cut for outside roof
1.35 - 1.70 1.0
1.3
0.12
0.18
Ψ (2D) (W/mk)
- - - - -
- 0.12 0.09 0.12
3.60
Χ (3D) (W/k)
0.161 0.277 0.732 0.114 1.130
0.010 -
-
-
Category
Acceptable quality (legal until August 2011)
Average quality (legal until September 2011)
Good quality
high quality
aGC GLaSS BuILDING
Demonstration quality (legal as of January 2021)
table 5. ew levels
ew level
Of ce and utility buildings
100
80
60
45
42
A nearly zero-energy building
umax (W/ m2k)
2.5 1.6
2.9
0.3
0.6 1.0 0.4 1.0
Rmin uplanned
(m2k/W) (W/m2k) (m2k/W)
Rplanned
table 3. Properties of the thermal bridges 2D and 3D
Since September 1, 2009, the building permit depends on the requirements set forth in Annex III of the EPB (Energy Performance of Buildings) being met. New of ce and utility buildings must achieve an Ew level below 80.