MAX Compared to XPS

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MAX Compared to XPS


There are many myths about the performance of Foam-Control MAX compared to XPS insulation.
Consider these facts and make an educated decision


Foam-Control MAX   XPS
ASTM C578 Standard Compliance.
Foam-Control MAX is manufactured in compliance with ASTM C578, “Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation”.
ASTM C578 Standard Compliance.
XPS is manufactured in compliance with ASTM C578, “Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation”.
UL Recognition.
Foam-Control MAX is recognized in UL ER11812-05 evaluation report.
Limited Recognition.
Code reports for XPS are not available from UL. Some, but not all manufacturers have ICC-ES reports.
Closed Cell Polystyrene Foam Filled with Air.
Foam-Control MAX is a closed cell foam. It is manufactured from graphite enhanced expanded polystyrene resin which is molded into blocks. Foam-Control MAX contains air within the closed cells.
Closed Cell Polystyrene Foam Filled with an Unknown Gas.
XPS is a closed cell foam. It is manufactured from polystyrene, blowing agents, and dyes which are extruded into boards. XPS generally contains HFC’s such as HFC 134a within the closed cells. HFC’s are harmful to the environment.
R-value: Stable Long-Term.
Foam-Control MAX is stable and the R-value will not change with time.
R-value: Loses R-value over Time.
XPS is not stable and the R-value will drop over time as the cell gases escape.
Excellent Water Resistance.
Foam-Control MAX is a closed cell polystyrene foam which is naturally water resistant. Expanded polystyrene produts have demonstrated lower water absorption than XPS in several longterm exterior exposure studies. Don’t be fooled by comparisons using short term laboratory tests which are conducted for only 24 hours.
Excellent Water Resistance.
XPS is a closed cell polystyrene foam which is naturally water resistant. The water resistance of XPS is published for exposure to water in a laboratory after only 24 hours. Short term laboratory results do not correlate to long-term performance of XPS in exterior exposure conditions.
R-value: Water Exposure.
Foam-Control MAX is manufactured to resist moisture absorption in wetting conditions and release absorbed moisture quickly during drying periods, which means Foam-Control MAX maintains R-value.
R-value: Water Exposure.
XPS is manufactured to resist moisture absorption in wetting conditions, but long-term in-situ testing has shown XPS traps water due to its low drying potential.  This means XPS loses R-value.
Vapor Permeance.
The vapor permeability of Foam-Control MAX ranges from 2.5 to 5.0 perms for a 1 in. thick material. This is approximately 2-3 times better than XPS.
Vapor Permeance.
The vapor permeability of XPS is typically 1.5 perms for a 1 in. thick material. XPS over 1.5 in. thick will act as a vapor retarder which may trap moisture in some climate zones.
Don’t Compromise, Foam-Control MAX insulation provides more thermal resistance (R-value) per dollar.

Selecting Comparable MAX and XPS Insulations

  Foam-Control MAX Compared to XPS