General
- avoidance of mould growth and surface condensation, and
- limiting factors governing additional heat losses.
D.2 Mould growth and surface condensation
- Tsi = minimum internal surface temperature,
- Te = external temperature, and
- Ti = internal temperature.
D.3 Linear thermal transmittance and additional heat loss
D.4 Calculation procedures
Table HL15A - Section 1 - Cavity wall insulation - Extract from TGD L
Table HL15B - Section 1 - Cavity wall insulation (contd...) - Extract from TGD L
- ψ values for a Target U-value for the wall of 0.18 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.13 to 0.16 W/m2K;
- Flat Roof = 0.16 to 0.20 W/m2K;
- Ground Floor = 0.16 to 0.21 W/m2K.
- ψ values for a Target U-value for the wall of 0.15 W/m2K can be used for a range of U-values from of 0.12 W/m2K to 0.17 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling 0.11 to 0.16W/m2K;
- Flat Roof = 0.11 to 0.17 W/m2K;
- Ground Floor = 0.12 to 0.18 W/m2K.
- Where two building elements have one U-value above its target while the other is below its target U-value, the aggregate percentage change from the respective target U-values in the table should not exceed +20 % for the Psi (ψ) value to be valid, i.e. if for the 0.15 U-value wall, if the U-value was increased by 10 % above the wall target U-value (from 0.15 to 0.165), then the roof U-value could be at most 10 % below the roof target U-value (from 0.14 to 0.126), because the aggregate change would then be 20 %.
- This is an externally supported balcony (the balcony slab is not a continuation of the floorslab) where the wall insulation is continuous and not bridged by the balcony slab.
- Value of Ψ is applied to each dwelling.
- Psi value is for whole junction. Half the value should be applied to each dwelling on either side of the junction
Table HL16 - Section 2 - External insulation - Extract from TGD L
- ψ values for a Target U-value for the wall of 0.18 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.13 to 0.16 W/m2K;
- Flat Roof = 0.16 to 0.2 W/m2K;
- Ground Floor = 0.16 to 0.21 W/m2K.
- ψ values for a Target U-value for the wall of 0.15 W/m2K can be used for a range of U-values 72 from of 0.12 W/m2K to 0.17 W/m2K for theconstruction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling 0.11 to 0.16 W/m2K;
- Flat Roof = 0.11 to 0.17 W/m2K;
- Ground Floor = 0.12 to 0.18.
- Where two building elements have one U-value above its target while the other is below its target U-value, the aggregate percentage change from the respective target U-values in the table should not exceed +20 % for the Psi (ψ) value to be valid, i.e. if for the 0.15 U-value wall, if the U-value was increased by 10 % above the wall target U-value (from 0.15 to 0.165), then the roof U-value could be at most 10 % below the roof target U-value (from 0.14 to 0.126), because the aggregate change would then be 20 %.
- This is an externally supported balcony (the balcony slab is not a continuation of the floorslab) where the wall insulation is continuous and not bridged by the balcony slab.
- Value of Ψ is applied to each dwelling.
- Psi value is for whole junction. Half the value should be applied to each dwelling on either side of the junction.
Table HL17 - Section 3 - Internal insulation - Extract from TGD L
Table HL18A - Section 4 - Timber frame construction - Extract from TGD L
- ψ values for a Target U-value for the wall of 0.18 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.13 to 0.16 W/m2K;
- Flat Roof = 0.16 to 0.2 W/m2K;
- Ground Floor = 0.16 to 0.21 W/m2K.
- ψ values for a Target U-value for the wall of 0.15 W/m2K can be used for a range of U-values 75 from of 0.12 W/m2K to 0.17 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling 0.11 to 0.16W/m2K;
- Flat Roof = 0.11 to 0.17 W/m2K;
- Ground Floor = 0.12 to 0.18.
- Where two building elements have one U-value above its target while the other is below its target U-value, the aggregate percentage change from the respective target U-values in the table should not exceed +20 % for the Psi (ψ) value to be valid, i.e. if for the 0.15 U-value wall, if the U-value was increased by 10 % above the wall target U-value (from 0.15 to 0.165), then the roof U-value could be at most 10 % below the roof target U-value (from 0.14 to 0.126), because the aggregate change would then be 20 %.
- This is an externally supported balcony (the balcony slab is not a continuation of the floorslab) where the wall insulation is continuous and not bridged by the balcony slab.
- Value of Ψ is applied to each dwelling.
- Psi value is for whole junction. Half the value should be applied to each dwelling on either side of the junction.
Table HL19A - Section 5 - Steel frame construction - Extract from TGD L
- ψ values for a Target U-value for the wall of 0.18 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.13 to 0.16 W/m2K;
- Flat Roof = 0.16 to 0.2 W/m2K;
- Ground Floor = 0.16 to 0.21 W/m2K.
- ψ values for a Target U-value for the wall of 0.15 W/m2K can be used for a range of U-values from of 0.12 W/m2K to 0.17 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling 0.11 to 0.16 W/m2K;
- Flat Roof = 0.11 to 0.17 W/m2K; 77
- Ground Floor = 0.12 to 0.18.
- Where two building elements have one U-value above its target while the other is below its target U-value, the aggregate percentage change from the respective target U-values in the table should not exceed +20 % for the Psi (ψ) value to be valid, i.e. if for the 0.15 U-value wall, if the U-value was increased by 10 % above the wall target U-value (from 0.15 to 0.165), then the roof U-value could be at most 10 % below the
roof target U-value (from 0.14 to 0.126), because the aggregate change would then be 20 %. - This is an externally supported balcony (the balcony slab is not a continuation of the floorslab) where the wall insulation is continuous and not bridged by the balcony slab.
- Value of Ψ is applied to each dwelling.
- Psi value is for whole junction. Half the value should be applied to each dwelling on either side of the junction.
Table HL20A - Section 6 - Hollow block construction - Extract from TGD L
- ψ values for a Target U-value for the wall of 0.18 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.13 to 0.16 W/m2K;
- Flat Roof = 0.16 to 0.2 W/m2K;
- Ground Floor = 0.16 to 0.21 W/m2K.
- ψ values for a Target U-value for the wall of 0.15 W/m2K can be used for a range of U-values from of 0.12 W/m2K to 0.16 W/m2K for the construction type specified. The U-values of the flanking elements to the wall can vary from the flanking element target U-value as follows:
- Pitched roof insulation on slope, insulation on ceiling = 0.11 to 0.16 W/m2K;
- Flat Roof = 0.11 to 0.17 W/m2K;
- Ground Floor = 0.12 to 0.18.
- Where two building elements have one U-value above its target while the other is below its target U-value, the aggregate percentage change from the respective target U-values in the table should not exceed +20 % for the Psi (ψ) value to be valid, i.e. if for the 0.15 U-value wall, if the U-value was increased by 10 % above the wall target U-value (from 0.15 to 0.165), then the roof U-value could be at most 10 % below the roof target U-value (from 0.14 to 0.126), because the aggregate change would then be 20 %.
- This is an externally supported balcony (the balcony slab is not a continuation of the floorslab) where the wall insulation is continuous and not bridged by the balcony slab.
- Value of Ψ is applied to each dwelling.
- Psi value is for whole junction. Half the value should be applied to each dwelling on either side of the junction.
Table HL21 - Example calculation of (y) value for DEAP for a 3 bed semi-detached house using the actual lengths of the internal ACD key junctions and their psi-values from Appendix D - Extract from TGD L