Division 7 Ebook Page 547 FOAMULARŪ XPS Insulation Limiting UV Exposure

Technical Bulletin FOAMULAR Extruded Polystyrene Insulation Limiting UV Exposure Owens Corning recommends covering FOAMULAR extruded polystyrene (XPS) rigid insulation as soon as possible following installation due to its sensitivity to ultra-violet light (UV). All polystyrene products slowly deteriorate if exposed to sunlight (UV), for long periods of time. If FOAMULAR XPS is not covered immediately, it is recommended that it be covered within 60 days. When exposed for up to 60 days, gradual color fading may occur. Fading or color loss, while quite noticeable, will not affect the performance of FOAMULAR XPS. The rate at which UV affects polystyrene is a function of the intensity of the UV exposure. Therefore, the rate varies between climates such as the cloudy Great Lakes region versus the desert southwest. It can vary locally day-to-day depending on cloud cover, or it can vary depending on orientation (horizontal versus vertical). Polystyrene insulation, when exposed, goes through stages of UV reaction: The first reaction to UV exposure is fading color. The colorant used to make FOAMULAR PINK will begin to pale usually in 14 to 28 days. Gradual color loss, although visually noticeable if exposure is prolonged, has no effect on the properties of the insulation board. Strength, thermal R-value, and moisture resistance properties will remain the same regardless of fading color. The second stage of UV deterioration is "powder/ chalking" on the FOAMULAR surface. This may begin in 60 to 90 days. If present, "powdering" can be felt and seen by lightly dragging a finger across the surface of the board. A very shallow trail will be left in the polystyrene surface if it has been damaged by UV exposure. The "powder" feel of the board is a thin layer of polystyrene cells that have been damaged by exposure to UV. When this happens, only the thin layer of cells on the surface of the board are damaged. FOAMULAR extruded polystyrene consists of millions of closed cells, surrounded by polystyrene cell walls. The closed cells contain a low conductivity gas for insulation value, and they resist water intrusion and give the board its strength. Beneath the thin UV damaged layer of cells on the surface are millions of fresh cells that are undamaged. Assuming that those undamaged cell layers are not similarly exposed, very little actual loss of physical properties will be experienced. Primarily the loss will be thermal resistance (R value) in proportion to the thickness lost. Surface water retention may be slightly increased due to the surface being "roughened" compared to its original smooth state, however, the net affect will be minimal. Over a long period of time, if the weathering process is allowed to continue to expose fresh layers, FOAMULAR XPS could begin to lose R-value as its thickness is slowly reduced by erosion. The potential for UV degradation is ended once the foam is covered because contact with sunlight (UV) is ended. FOAMULAR XPS R-value lost, if any, will be proportional to the amount of thickness lost to degradation. OWENS CORNING FOAM INSULATION, LLC ONE OWENS CORNING PARKWAY TOLEDO, OHIO 43659 1-800-GET-PINK www.owenscorning.com Pub. No. 10017763. Printed in U.S.A. August 2012. THE PINK PANTHER & 1964-2012 Metro-Goldwyn-Mayer Studios Inc. All Rights Reserved. The color PINK is a registered trademark of Owens Corning. 2012 Owens Corning. All Rights Reserved. Disclaimer of Liability Technical information contained herein is furnished without charge or obligation and is given and accepted at recipient's sole risk. Because conditions of use may vary and are beyond our control, Owens Corning makes no representation about, and is not responsible or liable for the accuracy or reliability of data associated with particular uses of any product described herein. Please contact 419-248-6557 for additional information. Email: gettech@owenscorning.com

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