NCC 2019 Volume One
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Specification J1.5b Spandrel panel thermal performance

Specification J1.5b Spandrel panel thermal performance

1. Scope

This Specification describes methods of determining the thermal performance of spandrel panels.
Intent

To detail how to calculate the thermal performance of spandrel panels.

2. Spandrel panel R-Value: Calculation method 1

Spandrel panels are deemed to have the thermal properties nominated in Table 2, where—

(a)

Configuration 1 consists of—

(i)

a thermally unbroken (bridged) frame; and

(ii)

a centre of spandrel panel consisting of—

(A)

a single-glazed opaque or clear face; and

(B)

a 100 mm air gap; and

(C)

a 3 mm aluminium, 0.8 mm galvanised steel or zinc back pan; and

(b)

Configuration 2 consists of—

(i)

a thermally unbroken (bridged) frame; and

(ii)

a centre of spandrel panel consisting of—

(A)

a double-glazed opaque face; and

(B)

a 50 mm air gap; and

(C)

a 3 mm aluminium, 0.8 mm galvanised steel or zinc back pan; and

(c)

Configuration 3 consists of—

(i)

a thermally unbroken (bridged) frame; and

(ii)

a centre of spandrel panel consisting of—

(A)

a double-glazed clear face; and

(B)

a 50 mm air gap; and

(C)

a 3 mm aluminium, 0.8 mm galvanised steel or zinc back pan; and

(d)

Configuration 4 consists of—

(i)

a thermally unbroken (bridged) frame; and

(ii)

a centre of spandrel panel consisting of—

(A)

a double-glazed low-e clear face; and

(B)

a 50 mm air gap; and

(C)

a 3 mm aluminium, 0.8 mm galvanised steel or zinc back pan; and

Table 2 Achieved Total R-Value of spandrel panels
Type No insulation R0.5 insulation R1.0 insulation R1.5 insulation R2.0 insulation
Configuration 1 0.3 0.39 0.42 0.44 0.45
Configuration 2 0.35 0.41 0.43 0.44 0.45
Configuration 3 0.84 0.96 1.03 1.07 1.09
Configuration 4 0.91 1.00 1.03 1.07 1.09
Intent

To detail the R-Values considered to be achieved by common forms of spandrel panels.

3. Spandrel panel R-Value: Calculation method 2

The Total system U-Value of a spandrel panel is determined in accordance with the following formula:

v1_SpecJ15b_2019.svg

where—

Acs = the area of the centre region of the spandrel panel; and
Aes = the area of the edge region of the spandrel panel, where the edge has a defined width of 127 mm; and
Afs = the area of the frame region of the spandrel panel; and
Ucs = the U-value of the centre region of the spandrel panel; and
Ues = the U-value of the edge region of the spandrel panel, where the edge has a defined width of 127 mm; and
Ufs = the U-value of the frame region of the spandrel panel; and
Usp= the Total system U-Value of the spandrel panel.

Intent

To detail how to calculate the Total System R-Value of spandrel panels.

This method has been provided to enable the calculation of the Total System R-Value of less common forms of spandrel panels not covered in Clause 2.