The area limits of the Table in Section 1745.10 may be increased in accordance with the following provisions of subsections (a) to (g) and, unless specifically prohibited, the increases shall be additive.
(a) Where an entire building is equipped with an approved automatic sprinkler system the limiting areas may be increased by 200 percent.
(b) Where a one-story building is equipped with an approved automatic sprinkler system and the average height to the roof or to a fireretardant ceiling does not exceed twenty-five feet, the limiting areas may be increased by 300 percent. No additional increase because of sprinklers shall be permitted for this condition.
(c) In Fire Zone No. 3, the limiting areas of buildings of unprotected noncombustible construction may be increased by seventy-five percent when all structural members including walls, columns, piers, beams, girders, joists, trusses, floors and roofs have a fire resistance rating of not less than one hour.
(d) In Fire Zone No. 3, the limiting areas of one-story buildings of heavy timber construction, ordinary construction and wood frame construction may be increased fifty percent (50%) when all structural members including columns, wall and partition studs and sheathing, floors and roofs are of approved fire retardant treated lumber that has been treated by a pressure impregnation process.
(e) In Fire Zone No. 3, the limiting areas on one-story buildings of ordinary and wood frame construction may be increased thirty-three and one-third percent when all structural members including walls, columns, beams, girders, joists, floors and roofs have a fire resistance rating of not less than one hour.
(f) Where a building of rectangular shape is erected on a corner lot so that two of its sides front on a street or on a public place twenty-one feet or more in width, unencumbered and accessible from a street, the limiting areas may be increased by fifty percent. Where a building is erected on a lot so that all of its sides front on a street or on a public place twenty-one feet or more in width, unencumbered and accessible from a street, the limiting areas may be increased by 100 percent. For any building not covered by the above two paragraphs of this subsection that has more than twenty-five percent of its perimeter fronting on a street or on a public place twenty-one feet or more in width, unencumbered and accessible from the street, the limiting areas may be increased in accordance with the following formula:
I = 2 AF 0.5A P |
in which:
I means the increase of area, in square feet;
A means the area limit of the Table in Section 1745.10, in square feet;
F means the frontage on a street or public place twenty-one feet or more in width, unencumbered and accessible from a street, in feet;
P means the building perimeter, in feet.
The increase in area permitted by this formula shall not exceed the area limit taken from the Table in Section 1745.10. In no case shall any side of a building that does not have suitable access openings, as defined in the BOCA Basic/National Building Code, to each story above the basement be given credit as frontage on a street or public place.
(g) In Fire Zone No. 3, buildings of noncombustible construction may be unlimited in area when complying with all the following provisions:
(1) Buildings of protected noncombustible construction shall not exceed two stories in height, not including basement, and buildings of unprotected noncombustible construction shall not exceed one story in height without basement.
(2) The entire building shall be equipped with an approved automatic sprinkler system except that buildings occupied exclusively by stocks of noncombustible material not packed or crated in combustible material need not be sprinklered.
(3) A horizontal separation of eighty feet shall be provided on all sides of buildings.
(4) Means of egress shall be provided ln accordance with the BOCA Basic/National Building Code.
(Ord. 6424. Passed 11-29-77.)