Rigid or semirigid thermal insulation having a thickness small in comparison to other dimensions; density usually about 4 to 16 lb per cu ft (64 to 256 kg per cu m); low structural strength.
Rigid or semirigid thermal insulation having a thickness small in comparison to other dimensions; density usually about 4 to 16 lb per cu ft (64 to 256 kg per cu m); low structural strength.