Delta MW and EPS-FR Panel Awning and Patio Roof System 
 
Revision 1-4 
37 
 
Appendix A  
Assessment of Heat Conduction Through a Steel 
Member 
A.1  Introduction 
A one-dimensional finite difference heat transfer calculation is undertaken to determine the temperature 
distribution through a steel purlin (approximated as a solid steel rod) when exposed on one face to a 
V2.3.1.3 fire source feature on the site boundary. The simplified model is shown in Figure 5-1.  
The aim of the assessment is to establish whether conduction through a steel member along the Type I 
panel (metal facings, metal support structure or metal plumbing fixtures) of the Delta MW and EPS-FR roof 
system may result in ignition of the EPS-FR core within the adjacent Type II panel of the roof system. 
 
 
Figure 5-1. Finite Difference Heat Transfer Analysis Paths to assess heat transfer through a steel 
member via conduction. 
 
A.2  Methodology 
The finite difference heat transfer equation used for calculating the temperature distribution through the 
steel rod is given below: 
𝑇𝑜′ = [𝑘𝑠𝐴(𝑇𝑛−1 −𝑇𝑛)
𝛿𝑥𝑛,𝑛−1
+ 𝑘𝑠𝐴(𝑇𝑛+1 −𝑇𝑛)
𝛿𝑥𝑛+1,𝑛
−ℎ𝐴(𝑇𝑜−20) −𝜀𝜎𝐴(𝑇𝑜4 −2934)] ×
𝛿𝑡
𝜌𝑐𝐴𝛿𝑥𝑜
+ 𝑇𝑜 
 
One-dimensional heat path 
through steel rod showing 
nodes used for heat 
transfer analysis 
(∆x = 0.1 m) Side attached to Class 1Side exposed toboundarySide exposed toboundarySide attached to Class 1
AXONOMETRIC VIEW FROM ABOVE 
AXONOMETRIC VIEW FROM BELOW 
Rate of conduction is proportional to 
cross-sectional area i.e. a higher rate of 
conduction is expected through a thick 
gauge steel member than through thin 
steel sheeting. As such, conduction is 
assessed through a steel purlin which is 
approximated as a steel rod. 
Solid cross-sectional area 
0.008 m2 
Face exposed to heat 
900mm 
Non-combustible 
portion within 900 
mm of site boundary 
(i.e. Panel Type I) 
Non-combustible 
portion within 
900 mm of site 
boundary 

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