The Exhibitor (Nov 1938-May 1939)

BETTER MANAGEMENT BM-13 mended and should not be used generally, particularly in concealed locations of nonfire-resistive construction, unless covered with a cement or gypsum plaster coating of 14inch thickness. On ducts with entering air temperatures exceeding 175 degrees Fahrenheit combustible coverings shall not be used. Repair work involving the use of torches should not be undertaken on ducts covered with combustible material until such material has been removed from that portion of the duct. Ducts shall be so constructed as to provide structural strength and durability at least the equivalent of galvanized sheet iron or steel of the thickness specified. Ducts shall be made reasonably tight throughout and shall have no openings other than those required for the proper operation and maintenance of the system. Return ducts, other than vertical, shall be so constructed that the interior is accessible to facilitate the cleaning of possible accumulations of dust and combustible material in them. Clean-out openings at approximately 20-foot intervals shall be provided where the ducts are of such size that they may not be readily entered to accomplish the cleaning. Supply ducts, other than vertical, shall conform to the above regulations for return ducts, unless all of the supply air passes through with water spray or filters. • INSTALLATION OF DUCTS. In no case shall the clearance from metal ducts to stored combustible material be less than six inches, and to combustible construction, including plaster on wood lath, it shall not be less than $4inch. Where ducts pass through walls, floors, or partitions, the space around the duct shall be sealed with rope asbestos, mineral wool, or other non-combustible material to prevent the passage of flame and smoke. Where ducts pass through concealed ceiling spaces of combustible material, or are located inside combustible partitions or walls, either the ducts or the interior surfaces of such concealed ceiling space, partition or walls shall be protected with J4-inch asbestos or other approved insulating material or a clearness of 2'2-inch as specified in the preceding rule shall be maintained between ducts and all combustible construction. The integrity of fire stopping shall not be destroyed. The spaces between the ducts and the fire-stopping shall be filled with brick, asbestos, mineral wool, or other approved non-combustible material. Ducts which pass through floors of “fireproof construction,” "semi-fireproof construction,” or heavy timber construction, in which vertical openings are generally protected, shall be incased in a 4-inch clay tile, 4-inch gypsum block, or their equivalent. Such construction, however, shall not be required for branches which are cut off from the main portion of the duct by approved fire dampers. No room, attic, concealed space or otherportion of a building shall be used as an integral part of a duct sustem, unless it conforms to all the requirements for ducts. Such arrangements shall be subject to the approval of the inspection department having jurisdiction. Plenum chambers, which conform to all the requirements for ducts, may be located in any such portion of the building; such chambers shall not be used for storage or occupational purposes. Ducts shall not be built into a building in such a way as to impair the effectiveness of the fire-proofing around steel or iron structural members, such as placing ducts between fire-proofing and the members protected. Ducts should not be located where they will be subject to damage or rupture. Where so located, they shall be suitably protected. Ducts shall be reasonably supported. Hangers and brackets for supporting ducts shall be of metal. • AUTOMATIC FIRE DOORS AND DAMPERS. The passing of ducts through fire walls should be avoided wherever possible. When ducts or the outlets from or inlets to them pass through fire walls, they shall be provided with automatic fire doors on both sides of the wall through which they pass. On small openings not exceeding 18 inches in diameter, 2'8-inch steel plates may be used in lieu of fire doors. (NOTE. A fire wall is defined in the Building Code recommended by the National Board of Fire Underwriters as “a wall which subdivides a building or separates buildings to restrict the spread of fire, and which starts at the foundation and extends continuously through all stories to and above the roof.”) Fire dampers installed in the system, as required at other than fire-wall openings, shall be No. 16 U. S. gauge metal on ducts up to 18 inches in diameter or greatest width, No. 12 U. S. gauge on diameters up to 3 6 inches or greatest width, and No. 7 U. S. gauge on ducts above 3 6 inches in width. One-half-inch approved rigid asbestos sheet material may be used at points where metal dampers are specified, when permission of the inspection department having jurisdiction is granted. Fire doors and fire dampers shall be arranged to close automatically and remain tightly closed, upon the operation of a fusible link or other heat actuated device located where readily affected by an abnormal rise of temperature in the duct. Hinged dampers shall be equipped with spring catches and pins of hinges shall be of corrosion-resistant material. An approved fire damper shall be provided on each opening through a required fire partition. (NOTE; A fire partition is defined in the Building Code recommended by the National Board of Fire Underwriters as “a wall or partition which subdivides a story of a building to restrict the spread of fire or to provide an area of refuge” and to be so classed must have a fire-resistance rating of not less than two hours. A required fire partition is one which is required by the provisions of said building code or by the regulations applying to some specific occupancy.) Where ducts pass through floors, approved fire dampers shall be provided at each outlet, inlet, and branch opening in such main vertical duct. Where such ducts serve only one floor, only one fire damper shall be required in the main supply duct from the unit and one in the return. Outside air intake openings shall be protected with approved automatic fire doors or dampers, except where permission to omit them, because of light exposure, is granted by the inspection department having jurisdiction. Where deemed necessary by inspection department having jurisdiction, approved heat-actuated devices shall be installed at intake openings to shut fans down in case of exposure fires. Fire doors at openings through fire walls and fire dampers at fire partitions shall be so arranged that the disruption of the duct w ll not cause failure to protect the opening. (NOTE: This may be accomplished by locating the fire door or damper in a collar securely fastened to the wall.) • AIR INTAKES AND OUTLETS. Air shall not be re-circulated from any space in which objectionable quantities of flammable vapors, flyings, or dust are given off. Air inlet and outlet openings shall be located at least three inches above the floor, except that protected floor inlets may be permitted, under seats, in theatres. When located less than seven feet above the floor, inlet and outlet openings shall be protected by a substantial grille or screen, through the openings in which a half-inch sphere will not pass. • AIR FILTERS. Combustible air filters should not be used unless they are in them ADD New BOX OFFICE APPEAL WITH STANLEY MAGIC DOORS Advertise "The Theatre with the Magic Doors” and you have a decided edge over competition when it comes to packing em in. These doors, which open automatically at a patron's approach, have real publicity value and real box-office appeal. Wherever they have been introduced, they have attracted wide attention and interest. In addition to the prestige they bring, Stanley Magic Doors save air conditioning and cut down costs, by admitting the maximum number of customers with the minimum number of openings. Write for information today. The Stanley Works, New Britain, Connecticut. STANLEY MAGIC \ DOORS / *o hano ^ March 15, 1533 TRI