# J4D6 Walls and glazing ## What is J4D6 Walls and Glazing? J4D6 Walls and Glazing outlines the energy efficiency requirements for wall-glazing construction, focusing on both thermal and solar performance. Key points include: ### Total System U-Value: * Wall-glazing constructions must meet specific U-Value limits, which represent the overall thermal conductivity of the system. The limits vary by building classification: * For Class 2 common areas and Classes 5, 6, 7, 8, 9b, and non-ward areas of Class 9a buildings: U2.0. * For Class 3, 9c, and ward areas of Class 9a buildings: * U1.1 in climate zones 1, 3, 4, 6, or 7. * U2.0 in climate zones 2 or 5. * U0.9 in climate zone 8. * Display glazing is limited to U5.8. ### Calculation of U-Value: The U-Value for wall-glazing construction must be calculated according to Specification 37. ### Wall Components' R-Value: Wall components must achieve a minimum Total R-Value based on the percentage of wall area in the wall-glazing construction: * If less than 80% of the area: R1.0. * If 80% or more of the area: the value specified in Table J4D6a. #### Table J4D6a Minimum wall Total R-Value - Wall area 80% or more of wall-glazing construction area
Climate zoneClass 2 common area, Class 5, 6, 7, 8 or 9b building or a Class 9a building other than a ward areaClass 3 or 9c building or Class 9a ward area
12.43.3
21.41.4
31.43.3
41.42.8
51.41.4
61.42.8
71.42.8
81.43.8
### Solar Admittance: * Externally facing wall-glazing constructions (excluding wholly internal ones) must meet solar admittance limits specified in Table J4D6b for Class 2 common areas and Classes 5, 6, 7, 8, 9b, and non-ward areas of Class 9a buildings, and Table J4D6c for Class 3, 9c, and ward areas of Class 9a buildings. * Solar admittance must be calculated according to Specification 37. #### Table J4D6b Maximum wall-glazing construction solar admittance - Class 2 common area, Class 5, 6, 7, 8 or 9b building or Class 9a building other than a ward area | Climate zone | Eastern aspect solar admittance | Northern aspect solar admittance | Southern aspect solar admittance | Western aspect solar admittance | | ------------ | ------------------------------- | -------------------------------- | -------------------------------- | ------------------------------- | | 1 | 0.12 | 0.12 | 0.12 | 0.12 | | 2 | 0.13 | 0.13 | 0.13 | 0.13 | | 3 | 0.16 | 0.16 | 0.16 | 0.16 | | 4 | 0.13 | 0.13 | 0.13 | 0.13 | | 5 | 0.13 | 0.13 | 0.13 | 0.13 | | 6 | 0.13 | 0.13 | 0.13 | 0.13 | | 7 | 0.13 | 0.13 | 0.13 | 0.13 | | 8 | 0.20 | 0.20 | 0.42 | 0.36 | #### Table J4D6c Maximum wall-glazing construction solar admittance - Class 3 or 9c building or Class 9a ward area | Climate zone | Eastern aspect solar admittance | Northern aspect solar admittance | Southern aspect solar admittance | Western aspect solar admittance | | ------------ | ------------------------------- | -------------------------------- | -------------------------------- | ------------------------------- | | 1 | 0.07 | 0.07 | 0.10 | 0.07 | | 2 | 0.10 | 0.10 | 0.10 | 0.10 | | 3 | 0.07 | 0.07 | 0.07 | 0.07 | | 4 | 0.07 | 0.07 | 0.07 | 0.07 | | 5 | 0.10 | 0.10 | 0.10 | 0.10 | | 6 | 0.07 | 0.07 | 0.07 | 0.07 | | 7 | 0.07 | 0.07 | 0.07 | 0.07 | | 8 | 0.08 | 0.08 | 0.08 | 0.08 | 5. SHGC for Display Glazing: The Total System SHGC (Solar Heat Gain Coefficient) of display glazing must not exceed 0.81 divided by the applicable shading factor outlined in S37C7. #### Table S37C7a Shading multipliers — Northern, eastern and western aspects | G/H | P/H = 0 | P/H = 0.1 | P/H = 0.2 | P/H = 0.3 | P/H = 0.4 | P/H = 0.5 | P/H = 0.6 | P/H = 0.7 | P/H = 0.8 | P/H = 0.9 | P/H = 1 | | --- | ------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | ------- | | 0 | 1.00 | 0.90 | 0.80 | 0.72 | 0.64 | 0.57 | 0.51 | 0.46 | 0.41 | 0.38 | 0.35 | | 0.1 | 1.00 | 0.95 | 0.89 | 0.81 | 0.74 | 0.66 | 0.59 | 0.52 | 0.47 | 0.42 | 0.40 | | 0.2 | 1.00 | 0.98 | 0.94 | 0.89 | 0.82 | 0.75 | 0.68 | 0.62 | 0.56 | 0.51 | 0.47 | | 0.3 | 1.00 | 1.00 | 0.97 | 0.94 | 0.89 | 0.84 | 0.78 | 0.72 | 0.66 | 0.61 | 0.57 | | 0.4 | 1.00 | 1.00 | 1.00 | 0.99 | 0.97 | 0.90 | 0.84 | 0.77 | 0.73 | 0.68 | | | 0.5 | 1.00 | 1.00 | 1.00 | 1.00 | 0.99 | 0.97 | 0.92 | 0.90 | 0.86 | 0.83 | 0.79 | #### Table S37C7b Shading multipliers — Southern aspect | G/H | P/H = 0 | P/H = 0.1 | P/H = 0.2 | P/H = 0.3 | P/H = 0.4 | P/H = 0.5 | P/H = 0.6 | P/H = 0.7 | P/H = 0.8 | P/H = 0.9 | P/H = 1 | | --- | ------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | --------- | ------- | | 0 | 1.00 | 0.93 | 0.87 | 0.82 | 0.77 | 0.73 | 0.69 | 0.65 | 0.62 | 0.60 | 0.58 | | 0.1 | 1.00 | 0.97 | 0.93 | 0.88 | 0.84 | 0.79 | 0.75 | 0.71 | 0.67 | 0.64 | 0.62 | | 0.2 | 1.00 | 0.98 | 0.96 | 0.93 | 0.89 | 0.85 | 0.81 | 0.77 | 0.73 | 0.70 | 0.68 | | 0.3 | 1.00 | 0.99 | 0.98 | 0.96 | 0.93 | 0.90 | 0.87 | 0.83 | 0.80 | 0.77 | 0.74 | | 0.4 | 1.00 | 1.00 | 0.99 | 0.98 | 0.96 | 0.94 | 0.91 | 0.89 | 0.86 | 0.84 | 0.81 | | 0.5 | 1.00 | 1.00 | 0.99 | 0.99 | 0.98 | 0.96 | 0.95 | 0.93 | 0.91 | 0.90 | 0.88 | ### J4D6 Walls and glazing on Better Building Speckel automatically checks the provisions of J4D6 Walls and glazing against your design, as per Specification 37 Calculation of U-Value and solar admittance. Models can be simulated with simple DTS shading multipliers (Table S37C7a + S37C7b) or can be generated to produce a Performance Solution.