DeltaDualCore™ Panel Awning Systems Revision 1-12 37 Figure 4-14. Radiative heat transfer from the site boundary to the nearest point of the combustible roof covering for the DtS base case and performance solution case (point F). A 1-dimensional finite difference calculation is undertaken to assess the effect of conduction on heat transfer to the combustible portion of the roof system; refer to Appendix A. As shown in Figure 5-2, the results indicate that conductive heat attenuates quickly along the length of the steel rod and has no significant impact on the steel temperatures at a distance over 900 mm from the site boundary. The finite difference calculation assumes a solid rod with a cross section of 0.008 m2 which far exceeds that of a lightweight roof purlin. As such the conduction assessment is conservative and conduction to a much lesser degree would be expected in a real fire condition. Thus, conduction is not considered to present a dominant mechanism for heat transfer to the combustible component of the DeltaDualCore™ roof system. The risk of fire spread from the site boundary to the combustible portion of the roof system is therefore demonstrated to be no worse than that of the DtS base case, therefore satisfying the performance requirement. 4.8.2.4 Supplementary Discussion NCC 9.2.9(4) permits combustible fascia’s within 900mm but not closer than 450 mm from the site boundary as shown in Figure 4-15. Furthermore, non-combustible plumbing fixtures may be fitted within the 450 mm region as it is not considered to increase the risk of fire spread between neighbouring building due to it being non-combustible. This forms the basis of the proposed performance solution. The portion of the roof system which is combustible is suitably separated from the site boundary to the degree necessary to reduce the risk of fire spread between buildings. The non-combustible portion of the roof which (as demonstrated in Sections 4.8.2.1 to 4.8.2.3) does not increase the risk of fire spread between buildings and is therefore permitted to extend to the site boundary. The assessment considers the potential for fire spread from the site boundary to a combustible component of the roof system and vice versa. The thickness of the core material of each roof panel does not impact the likelihood of fire spread from the site boundary to the roof, or from the roof to the site boundary (as the thickness would be identical for the DtS base case and the performance solution case). As such, increasing or decreasing the roof panel thickness does not increase the risk of fire spread between buildings when compared to the DtS base case. As such, the assessment is independent of the thickness of the core material used in the roof system. The assessment has demonstrated achievement of performance requirement H3P1. 900 mm set back from site Site Boundary Combustible roof Non-combustible Radiative heat F F PERFORMANCE SOLUTION CASE DTS BASE CASE Class 1 Class 1
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