706.4.1 Townhouse Fire Separation
Each townhouse shall be considered a separate building and shall be separated from adjoining townhouses by a party wall complying with Section 706.1.1 or by the use of separate exterior walls meeting the requirements of Tables 601 and 602 for zero clearance from property lines as required for the type of construction. Separate exterior walls shall include one of the following:
- A parapet not less than 18 inches (457 mm) above the roof line.
- Roof sheathing of noncombustible material or fire retardant treated wood, for not less than a 4-foot (1219 mm) width on each side of the exterior dividing wall.
- One layer of 5/8-inch (15.9 mm) Type X gypsum board attached to the underside of roof decking, for not less than a 4-foot (1219 mm) width on each side of the exterior dividing wall.
- Such wall shall provide not less than a 2-hour fire-resistance rating. Plumbing, piping, ducts, electrical or other building services shall not be installed within or through the 2-hour wall, unless such materials and methods of penetration have been tested in accordance with Section 703.
- Such wall shall be continuous from the foundation to the underside of no less than a 4-foot (1219 mm) width on each side of the wall, shall be of noncombustible material, or fire-retardant-treated wood, or one layer of 5/8-inch (15.9 mm) Type X gypsum wallboard attached to the underside of the roof decking.
- Each dwelling unit sharing such wall shall be designed and constructed to maintain its structural integrity independent of the unit on the opposite side of the wall.