Rigid Insulation vs EPS Foam - Weights of Materials

[gramy13]

The weights of material table in the steel manual and the minimum design dead loads table in ASCE-7 lists rigid insulation at 1.5 psf per 1" of thickness. Does anybody know what type of rigid insulation this is? It's heavy. EPS foam is typically around 1 psf per 12" of thickness (1 pcf). Thanks!

 

[JedClampett]

Seems to be a conservative disconnect in the code values and actual weights. [link firestonebpco.com/content/.../Item1234_PolyisoFamilyBrochWeb%201.19.12.pdf]Firestone[/url] lists the weights of their Polyisocyanurate insulation as 2 pcf.