Arizona republican., 1916-02-17

and soffits of stairs. shall be meta. lathel and plastered. No studdng shall be less than two by four inches iii cross section.
 Sect. ,. Structural metal. Every beam carving masonry and all col nmns in class "B' buildings and struc- lures shall be fireproOfed as provided in class "A" buildings and structures All exposed parts of other structural metal shall he covered with metal lath on metal turing and plastered leaving an air space of not less than onehalf inch behind such lath and plaster.
 Sect. ,. Construction of floors. In buildings and structures of class B" all floors, ceiling jOists and roof joists may be of wood. Every floor shall be composed of two layers of flooring, each O: which shall be not less than seven-eights of an inch thick. with one inch of non- -oombustible material placed between the layers of the floor ing and extending over the entire area tO all fixtures and structural parts of such buildings or structures which pass through the floors and between turing strips. Under such layers of non -combustible material there shall be placed a full layer of waterproof paper or the floor may be constructed with a layer of two-inch tonged or groovcd planking and a layer of one inch flooring. with a layer of water proof paper between such layers of flooring. or of two thicknesses of as nestos paper between the layers of such flooring. All waterproof paper shall he turned up at least two inches where it comes in contact with the walls of any fixture or structural part of such building or structure passing through the floor
 Sect. 4. Bridging. In buildings and structures of class B" construction all wood ioists shall have at least one row of cross bridging of not less than four square inches sectional area to each twelve foot of span or fraction thereof
 All spaces between joists shall be flocked solid at each bearing partition with blocks not less than two inches thick and of the full height of the 1oists
 Each stud partition shall have two inch bridging the full length of the studs at the floor and ceiling and one TOW of two-inch bridging between the floor and ceiling; provided. that where two-inch plates the full width of studs are nsad at the floor and ceiling. bridging at the floor and ceiling shall not be required.
 Sect ,. Interior non bearing parti- tions. In buildings and structures of class "B' construction. interior non- bearing partitions shall be constructed Cf studs not less than two inches by three inches and metal lathed and plastered or such non bearing parti- tiOns may be constructed of hollow terra cotta tile in accordance with the provisions of this ordinance. or of metal studs. lathed with metal lath and plastered: or such non- bearing partitions may be constructed of studs not less than one inch by two inches lathed on both sides with metal lath and plastered with cement mOtar of such thickness that the finished parti- tion shall be not less than two inches in thickness. In order to make the mortar adhere to the studs, each such stud shall have securely fastened thereto strip of metal lath equal to the full width and length of each such stud, or shall have nails of size not less than four penny, common, driven not more than two inches apart into each such stud and left with the heads of such nails projecting from the face of such stud not less than one hall inch.
 Sect 6. Stairways. Buildings and structures of class "B'' shall have one main interior stairway not less thar fcur feet wide, from the first to the topmOst story. but in no case shal there be less than two interior stair ways from the ton floor to the second floor in any building or structure o more than seven thousand square fee of second floor area, and every suct building or structure shall have a least one interior stairway removed not less than ten feet from any ele- vator shaft or open well hole, and on' interior stairway to the roof.
 Every building and structure Q class B" having more than 14,0Ol square feet of floor area on each flool shall have added to it's interior stair way not less than two feet in width from the first to the tOpmost story and two additional feet in width added to such stairways for each additiona 5000 square feet or fractional par thereof. to such floor area; provided however, that where such building oi structures used for. or intended or de signed to be used for. store purpose: above the first floor. then such build ing shall be equipped with interior stairways as follows For 5000 square feet of floor area or less, at least Ont main stairway. not less than four fec wide. from the first to the topmost story: and for each additional 4,00i aouare feet or fractional part thereof il addition to said 5000 square feet ot floor area two additional feet il width shall be added to such stair way.
 Stairways from the first story tC any basement or portion thereof Of any such building or structure, occu- pied only for storage or for the main tainance of service for such building or structure shall be constructed of fireproof material throughout, ant shall be closed at some point with a tight fireproof partition and fireproot door containing no glass other thar wired glass not less than one fourth o-- an inch thick.
 Sect :. Elevator, dumb walters ant chutes. All passenger elevators ir buildings and structures of class "B' shall be enclosed in a shaft having { covered top: said shaft shall exten(