We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.
Solid Foam Product Insulating Products - Rigid Polystyrene, Polyurethane, Polyisocyanurate Insulation products will not contain asbestos fibers and most of these products are rather mold resistant, possibly because of their chemistry or because closed-cell foam insulations simply do no take up and hold the moisture that is required for active mold growth on or in building insulations or surfaces.
See INSULATION R-Values & Properties for R-value and other properties of nearly all historic insulating materials as well as contemporary building insulation products. [ASHRAE Fundamentals Handbook.]
To compare insulating material R-values see our Table of Properties of Insulating Materials
Also see MOLD in FOAM INSULATION, RESISTANCE, see Mold On Foam Insulation for a discussion of when and why we find mold growth on foam insulating materials like foam board and air handler foam insulating board.
Details are at FIRE PROTECTION FOR FOAM BOARD INSULATION. Excerpts are just below.
Foam insulation board should not be left exposed in building interiors.
While many modern foam insulating products do not themselves readily support combustion (that is they don't catch fire and burn alone) they may give off thick acrid or toxic black smoke in a fire, making it difficult to safely exit the burning building.
In the photograph at left, foam insulating board is shown on a garage ceiling below a second floor bedroom - this material should have been covered with fire rated drywall to meet local building code specifications for fire safety