Hello,
I am trying to model a lead roof using hevacomp to calculate the heat loss through a lead roof but I cannot find lead as a layer option when creating a new roof in the Fabric Data tab. Does anyone have any advice on this? I have tried adding a solid material but I cannot find the value for the vapour resistivity of lead anywhere.
Many thanks
Hi GarethCIBSE Guide A (1999), appendix 3.A7, Table 3.41 gives the following for lead:
Density 11340 kg/m³Thermal Conductivity: 35 W/mºCSpecific Heat: 130 J/kgºCTable 3.48 gives ALL metals an infinite Vapour Resistivity. We generally have metals set to 50,000 Gns/kgm, so that would seem a reasonable figure to use.The Fabric program has a limit of 5000 Gns/kgm for Special Solid Surfaces, so you may wish to use the DMAT program (available in the Mechanical Design section) to add Lead to the Metals class.Regards,
Duncan Brown
Answer Verified By: Gareth Griffiths
Thanks very much for the reply. I will see if I can download the DMAT program to add Lead as a material.
Kind Regards
Gareth - you already have itRegards,