Section SPS 377.11 - Proscenium curtain(1) In every theater or assembly hall having a stage which is more than 6 feet higher or wider than the proscenium opening, the proscenium opening shall be provided with a rigid metal curtain or a curtain of asbestos conforming to the following specifications, or of equivalent approved construction.(a) Asbestos curtains shall be substantially woven of asbestos fiber not less than 95% pure and shall weigh not less than 21/2 pounds per square yard. There shall be incorporated into the yarn before weaving, either monel metal, nickel, brass or other metal or alloy, having no less strength than these metals at temperatures up to 1700º Fahrenheit and no less resistance to corrosion at ordinary temperatures.(b) All seams shall be vertical, shall be lapped not less than one inch and sewed in 2 rows with not less than 1/16 inch pure asbestos twine. At the top and bottom of the curtain a 21/ 2 inch (or larger) steel pipe shall be placed and shall be securely fastened in and covered by the curtain. The curtain shall overlap the proscenium wall not less than 12 inches at each side and at the top, and shall be guided at each side by metallic loops or rings sliding on a 3/8 inch steel cable or No. 6 U. S. Standard gauge wire.
(c) In addition to any decoration, the curtain shall be painted on both sides with a mineral paint, having a silicate of soda binder, which will completely fill the cloth. Filler paint shall have not less than 4 parts of casein in each 10 parts of silicate of soda. The paint shall be well brushed into the cloth so that no light or smoke can come through.(d) For curtains of any type, the connections between curtain and wall shall be made as nearly smoke-proof as possible. Smoke grooves or pockets shall be of structural steel shapes and plates not less than 1/4 inch thick. These grooves or pockets shall be not less than 14 inches deep and 6 inches wide and shall be set back from the face of the arch at least 6 inches. They shall extend from the stage floor to a point 3 feet above the top of the raised curtain, and shall be securely bolted to the proscenium wall.(e) Provisions shall be made to prevent the curtain from leaving or binding on the guides under any conditions. Appropriate limit chains shall be provided to stop the downward travel of the top of the curtain at a line not less than 12 inches above the top of the proscenium opening. No part of a curtain, nor any of the curtain guides, or equipment, shall be supported by, or fastened to, any combustible material.(f) The hoisting apparatus for the curtain shall be designed with a factor of safety of 8 or more.(g) Besides the regular operating mechanism there shall be an emergency device which will allow the curtain to drop by gravity. The device shall be so arranged that it can be easily operated by hand from each side of the stage and from the fly galleries, and also that its operation will be controlled by 135º fusible links, or other approved heat release devices, placed on each side of the stage, and when thus operated it shall descend at its normal rate of speed.(h) The curtain and its operating mechanism shall be so designed and constructed at all points, whether specifically mentioned or not, as to form an efficient and reliable barrier against fire and smoke, according to the best practice.(i) Detailed plans and specifications for all curtains and their operating mechanism shall be submitted to the department for approval before installation.Wis. Admin. Code Department of Safety and Professional Services SPS 377.11
1-2-56; renum. and am., Register, September, 1974, No. 225, eff. 10-1-74.