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
1
2.4
3.3
2
1.4
1.4
3
1.4
3.3
4
1.4
2.8
5
1.4
1.4
6
1.4
2.8
7
1.4
2.8
8
1.4
3.8
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
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
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
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
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
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 Speckel
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.
Last updated
Was this helpful?
