Division 7 Ebook Page 543 FOAMULARŪ XPS Insulation & Insulfoam R-Tech Comparison

Technical Review FOAMULAR Rigid Insulation and INSULFOAM R-Tech Comparison A Close look at XPS and EPS with a Polymeric Skinned Surface Performance shouldn't be just skin deep. For decades, countless building designers and engineers have found extruded polystyrene (XPS) insulation to be the perfect choice for a myriad of applications. XPS insulation has a long term stable thermal resistance of R-5 per inch, measured after real time aging. It's high resistance to moisture is due to its closed cell hydrophobic polystyrene polymer system, which achieves its resistance to water without relying on a facer or skinned surface. What is INSULFOAM R-TECH Board? The boards consist of an expanded polystyrene (EPS) core with faces laminated with polyethylene and polypropylene films, or an optional reflective metalized film facer. It is EPS, flat faces, square edges, in various lengths and widths, thicknesses up to 5", fanfold or standard configuration. The boards are ASTM C578 Type I, II, VIII or IX. How is R-Tech different than FOAMULAR Rigid Foam Extruded Polystyrene Insulation? The biggest difference is cell structure, that results in R-Tech having worse (higher) water absorption and worse (lower) R-value per inch. FOAMULAR Extruded Polystyrene (XPS) rigid foam insulation has very well defined, uniform closed cells with continuous walls. (See Figure 1) The hydrophobic (resists water) polystyrene polymer combined with closed cell walls results in a very low rate of water absorption in the FOAMULAR rigid foam insulation. EPS (See Figure 2) is comprised of polystyrene beads fused together under heat and pressure. 1. Extruded (XPS) 2. Expanded (EPS) 3. Expanded (EPS) with food color tracing paths of water intrusion Although the beads themselves are closed cell and hydrophobic, the air spaces between them allow water and air to penetrate the board structure. Unlike the homogeneous structure of XPS, the voids between EPS beads allow water and air to penetrate deep inside the board structure (See Figure 3). The air spaces in EPS contributes to lower R-value per inch of the board. The air spaces also provide a path for water penetration, raising water absorption. What is the actual water absorption of R-Tech board? EPS (R-Tech) absorbs more water than XPS (FOAMULAR rigid foam insulation). This is because of the voids between the beads. Even with the R-Tech film facer, the open edges of the product still allow water to intrude into the voids between the beads. Figure 1 compares ASTM C272 water absorption test results for R-Tech and FOAMULAR rigid foam insulation. Is R-Tech board an ASTM C578 Type IV product as implied in some Insulfoam literature? It is not. Type IV properties require, among other things, a minimum R-value of 5.0 per inch of thickness. In the same literature that states the product name "ASTM C578 R-Tech IV", an R- value of 4.5/inch is claimed. That is not Type IV compliant. Other R-Tech literature claims water absorption of < 1.0 % volume which is also not compliant with ASTM C 578 which requires 0.3 maximum % volume for Type IV material. Is it true that XPS has no 20 year warranty position as claimed in R-Tech literature? It is not true. FOAMULAR XPS rigid foam insulation is warranted for 90% of the published R-5 at 20 years with no exclusions for exposure to moisture or other conditions. Visit www. foamular.com to view and

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