This specification covers the standards for the types, physical properties and dimensions of cellular polystyrene boards with or without facings or coatings made by molding (EPS) or extrusion (XPS) of expandable polystyrene proposed for use as thermal insulation. This specification, however, does not cover laminated products manufactured with any type of rigid board facer including fiberboard, perlite board, gypsum board, or oriented strand board. All thermal insulation shall be of uniform density and shall contain sufficient flame retardants to meet the oxygen index of requirements. They shall also meet the physical requirements such as thermal resistance, compressive resistance, flexural strength, water vapor permeance, water absorption, dimensional stability, and oxygen index specified herein. This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.