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
Gareth - you already have itRegards,
Duncan Brown
Thanks very much for the reply. I will see if I can download the DMAT program to add Lead as a material.
Kind Regards
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,
Answer Verified By: Gareth Griffiths