(a) Unit Separation. Dwelling units or areas of regular human occupation in boathouses shall be separated from each other by wall and/or floor ceiling assemblies of not less than a one-hour fire-resistive rating when tested in accordance with ASTM E119. Fire-resistive-rated floor-ceiling and wall assemblies shall extend to and be tight against the exterior wall, and wall assemblies shall extend to the underside of the roof sheathing.
(b) Unit Separation Over Boatwells. Dwelling areas or areas of human occupation in boathouses that extend out and over the boatwells shall be separated horizontally from the boatwell by a ceiling/floor assembly of not less than a two-hour noncombustible fire resistive rating when tested in accordance with ASTM E119, and as listed in Underwriters Laboratory (U.L.) Fireresistance Directory, latest edition.
(c) Unit Separation Adjacent to Boatwells. Dwelling areas or areas of human occupation in boathouses that are adjacent to boatwells, either on the same property or adjoining property, shall be separated from the boat wells with a two (2) hour fire rated wall constructed of concrete masonry units or poured concrete. These two-hour fire walls shall not contain plumbing or mechanical equipment, ducts or vents in the wall or in the cavity of a common wall. Electrical installations are limited to electrical wire installed in raceways and electrical outlet boxes.
(d) Common Wall Continuity. The common wall that separates adjacent boathouses or adjacent boatwells shall be continuous from the foundation to other underside of the roof sheathing, deck or slab and shall extend the full length of the common wall.
(e) Common Wall Parapets. Parapets shall be provided for the wall separating individual boathouses as an extension of the common wall in accordance with the following:
(1) Where roof surfaces adjacent to the wall are at the same elevation, the parapet shall extend not less than thirty inches above the roof surfaces.
(2) Where roof surfaces adjacent to the wall are at different elevations and the higher roof is not more than thirty inches above the lower roof, the parapet shall extend not less than thirty inches above the lower roof surface.
Exception: A parapet is not required in the two cases above when the roof is covered with a minimum Class C roof covering, and the roof decking or sheathing is of noncombustible materials or fire-retardant-treated wood for a distance of four feet on each side of the wall, or one layer of five-eighths inch Type X gypsum board is attached to the underside of the roof decking or sheathing a distance of four feet on each side of the wall.
(3) A parapet is not required where roof surfaces adjacent to the wall are at different elevations and the higher roof is more than thirty inches above the lower roof. The wall construction from the lower roof to the underside of the higher roof deck shall have not less than a one-hour fire-resistive rating. The fire-resistive rating shall be rated for exposure from both sides.
(f) Fire Wall Structural Stability. Walls shall have sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall, and shall be constructed of any approved noncombustible materials providing the required strength and fire-resistance rating.
(g) Cutting Fire Walls. A wall eight inches or less in thickness shall not be cut for chases or socketed for insertion of structural members subsequent to erection.
(h) Combustible Insulation. The Code Official shall permit the application of cork, fiber board or other combustible insulation where laid up without intervening air spaces and attached directly to the face of the wall, and protected on the exposed surface as provided in Section 1709.0 of the OBC.
(i) Noncombustible Roofs. The common wall is permitted to terminate at the underside of the roof deck where the roof is of noncombustible construction and is properly firestopped at the wall.
(j) Combustible Roofs. The wall is permitted to terminate at the underside of the roof deck in Types 3, 4 and 5 construction as defined in the OBC, where all of the following conditions below are met.
(1) The wall is properly firestopped at the deck.
(2) The roof sheathing or deck is constructed of approved noncombustible materials or fire-retardant treated wood, for a distance of four feet (1219mm) on either side of the wall.
(3) Combustible material does not extend through the wall.
(4) The roof covering has a minimum of a Class C rating.
(k) Noncombustible Frame. The fire wall shall not be supported on the structural frame in buildings of noncombustible construction unless such supporting frame has a fire-resistance rating at least equal to that required for the fire wall.
(l) Offset Fire Walls. Where fire walls are offset at intermediate floor levels in protected skeleton-frame construction, the offset floor construction and the intermediate wall supports shall be constructed of noncombustible materials with a fire-resistance rating not less than that required for the fire wall.
(m) Firewall Openings. Standards as to firewall openings shall be governed by Section 705 of the OBC the provisions of which are incorporated by reference herein.
(n) Unit Separation From Adjacent Boatports or Open Boat Slips. Exterior walls of boathouses adjoining boatports or open boat slips shall be of a wall assembly of not less than a one-hour fire resistive rating when tested in accordance with ASTM E119.
(o) Water Level Barriers. All boatwells shall be separated from each other or from each dwelling area or from adjacent boatports or open boat slips with barriers of noncombustible material of minimum one-fourth inch thick steel plate or approved equal extending down to twelve inches minimum below low water datum.
Exception: Such water level barriers shall not be required between boatwells on the same property and/or within lot lines. In relation to boathouses and boathouse structures designed, engineered and constructed concurrently and as a group, a single water level barrier between boatwells as required by this section shall be acceptable.
(p) Structural Independence. Each individual boathouse and boatport shall be structurally independent.
Exceptions:
(1) Foundations supporting common walls.
(2) Nonstructural wall coverings.
(3) Flashing at termination of roof covering over common wall.
(Ord. 05-119. Passed 7-25-05.)