A recent clarification confirms that openings, including doors, can be permitted in fire walls that separate buildings on the same lot, provided certain conditions are met under the International Building Code (IBC).
The IBC treats each portion of a structure separated by a fire wall as a separate building. When the wall is not acting as a party wall (which prohibits all openings), Section 706.8 governs how openings can be incorporated. These openings must be fire-protected in compliance with Section 716 and cannot exceed 156 square feet per opening unless both buildings are fully sprinklered in accordance with NFPA 13. Additionally, at any given floor level, the combined width of openings cannot exceed 25 percent of the wall’s length.
The structural stability of a firewall is critical, since it must remain standing if one side collapses during a fire. Several construction methods meet this requirement, including freestanding walls, laterally supported walls, and double wall configurations. For masonry fire walls, resources such as NCMA TEK Bulletin 5-8B provide guidance. Double fire walls designed per NFPA 221 are considered to meet the stability requirement and may also have openings, as allowed by that standard.
A key distinction arises when comparing firewalls to back-to-back exterior walls with zero separation distance. In the latter case, Table 705.8 would prohibit any openings. While it is possible to design adjacent buildings with exterior walls rated equal to or higher than a fire wall, incorporating openings in such a design would likely require alternative approval from the building official.
In short, a connecting door through a code-compliant fire wall between buildings on the same lot is allowed, as long as the opening size, fire protection rating, and aggregate width limits are met, and the wall’s structural stability satisfies IBC requirements.
The IBC treats each portion of a structure separated by a fire wall as a separate building. When the wall is not acting as a party wall (which prohibits all openings), Section 706.8 governs how openings can be incorporated. These openings must be fire-protected in compliance with Section 716 and cannot exceed 156 square feet per opening unless both buildings are fully sprinklered in accordance with NFPA 13. Additionally, at any given floor level, the combined width of openings cannot exceed 25 percent of the wall’s length.
The structural stability of a firewall is critical, since it must remain standing if one side collapses during a fire. Several construction methods meet this requirement, including freestanding walls, laterally supported walls, and double wall configurations. For masonry fire walls, resources such as NCMA TEK Bulletin 5-8B provide guidance. Double fire walls designed per NFPA 221 are considered to meet the stability requirement and may also have openings, as allowed by that standard.
A key distinction arises when comparing firewalls to back-to-back exterior walls with zero separation distance. In the latter case, Table 705.8 would prohibit any openings. While it is possible to design adjacent buildings with exterior walls rated equal to or higher than a fire wall, incorporating openings in such a design would likely require alternative approval from the building official.
In short, a connecting door through a code-compliant fire wall between buildings on the same lot is allowed, as long as the opening size, fire protection rating, and aggregate width limits are met, and the wall’s structural stability satisfies IBC requirements.