Two methods are common for installing foam plastic insulation: in the stud cavity space that is frequently filled with fiberglass and outboard of the primary framing. The THERMAXâ„¢ Wall System combines these two approaches.
THERMAXâ„¢ (ci) Exterior Insulation is installed outboard of the steel studs, creating a continuous enclosed envelope. STYROFOAMâ„¢ Brand SPF (CM Series) is installed on the interior in the stud cavity space against the back side of the THERMAXâ„¢ (ci) Exterior Insulation.
Foam plastic insulation products have some of the most stringent requirements governing their use, especially in commercial construction. The 2006 IBC Chapter 26 (Plastic) regulates use of plastic materials used in construction. The prescriptive compliance path is laid out in Section 2603.5: "Exterior Walls of Buildings of Any Height." There are seven elements to this section of the code that define foam plastic insulation products and their specific use in a commercial wall of Type I, II, III or IV construction.
| THERMAXâ„¢ Wall System and the 2006 IBC Chapter 26Â | ||
| 2006 IBC | Section Name | Requirements/Results |
| 2603.5.1 | Fire-Resistance Rated Walls |
Commercial walls may need to meet fire-resistance requirements (ASTM E119, hourly rating) based on the type of construction, occupancy of the structure, or separation distance from other structures. The THERMAXâ„¢ Wall System, with brick veneer, has achieved a 1-hour rating as a non-load bearing wall assembly per assembly V482. This assembly may be accessed via the UL directory: http://database.ul.com/cgi-bin/XYV/cgifind.new/LISEXT/1FRAME/index.html |
| 2603.52 | Thermal Barrier |
Any foam plastic must be separated from the interior of a building by an approved thermal barrier per Section 2603.4. The THERMAXâ„¢ Wall System incorporates a 5/8" Type X gypsum layer on the interior of the steel studs to serve this purpose. |
| 2603.5.3 | Potential Heat |
The potential heat energy of foam plastic insulation in any portion of the wall cannot exceed the potential heat energy of the foam plastic insulation contained in the wall assembly tested in accordance with Section 2603.5.5. The National Fire Protection Association's NFPA 285 testing has been conducted on the THERMAX™ Wall System and approvals have been obtained with several veneers. The potential heat energy of THERMAX™ (ci) Exterior Insulation per NFPA 259 testing is approximately 9,000 Btu/lb. For STYROFOAM™ Brand SPF CM 2045 and CM 2060, it is 11,700 Btu/lb and 11,800 Btu/lb, respectively. |
| 2603.5.4 | Flame Spread and Smoke Developed Indices |
Foam plastic insulations must have a flame spread index of 25 or less and a smoke developed index of 450 or less as determined in accordance with ASTM E84. THERMAX™ (ci) Exterior Insulation complies with this requirement up to a maximum thickness of 4.25". STYROFOAM™ Brand SPF (CM Series) also complies with this requirement. |
| 2603.5.5 | Test Standard NFPA 285 |
The wall assembly must be tested in accordance with NFPA 285. The test is referred to in the industry as the Multistory Flammability Test. The THERMAX™ Wall System is approved with several veneer types per NFPA 285 testing. |
| 2603.5.6 | Label Required |
This section requires proper labeling of the foam plastic by an approved agency. The bundle unit label of THERMAXâ„¢ (ci) Exterior Insulation shows the Underwriters Laboratories (UL) logo as its approved agency. STYROFOAMâ„¢ Brand SPF (CM Series) shows either the UL or Southwest Research Institute (SwRI) logo as its approved agency. |
| 2603.5.7 | Ignition |
A wall assembly must not ignite from the exterior side of the wall when tested in accordance with NFPA 268. The following exceptions are approved as outside protection layers and can be used on the THERMAXâ„¢ Wall System to eliminate the need for testing:
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