OVERVIEW
In addition to all of the other basic fire-resistant construction requirements found in Section R302 of the IRC, specific requirements for use of FPIS on exterior walls are found in Section R316. In summary, the requirements of Section R316 are as follows:
- Labeling and identification – required on FPIS material or packaging; refer to Section R316.2
- Surface burning characteristics – required; maximum flame spread index and smoke-developed index of 75 and 450, respectively (unless tested per Section R316.5); refer to IRC Section R316.3.
- Thermal barrier – required for wood frame walls; typically not less than ½-inch-thick gypsum wallboard on interior side of wall or assembly tested per NFPA 275; refer to Section R316.4.
- Specific requirements – cover a range of specific applications to masonry or concrete construction, roofing, attics, crawlspaces, doors, backer-board, re-siding, and other applications; refer to IRC Section R316.5.
DESIGN RESOURCES: For additional information on fire safety compliant design of exterior wall assemblies of wood-frame construction with FPIS-ci, refer to the Technical Evaluation Report: Foam Plastic Insulating Sheathing Products in Type V Construction.
IMPORTANT TIP: FPIS manufacturers often conduct special code-compliance fire testing on their products to take advantage of the fire performance features of their specific FPIS products or assemblies. These may provide more efficient solutions, such as allowing use of FPIS without a separate thermal barrier or ignition barrier in certain applications.
NEXT STEP: With fire-safety provisions addressed in the specification of the FPIS material properties and other components of the wall assembly (e.g., thermal barrier), proceed to STEP 3.