Permanent window washing platforms and all parts and accessories necessary for their full operation shall comply with all the requirements of Chapter 14C-9 which are applicable to the type of equipment used and for the purpose for which the equipment is installed.
(a) Plans and drawings shall be submitted for permit and shall be certified by a licensed architect or structural engineer, licensed to practice by the state of Illinois.
(b) [Reserved.]
(c) Application for permit shall comply with Chapter 14A-4.
(d) Raising or lowering of the platform shall be power-operated by overhead machinery.
(e) All wiring shall be done to conform with the requirements of the Chicago Electrical Code for outdoor installation.
(f) Roof machinery.
(1) Roof machinery cars shall have a counterweight stabilizing factor of at least three to one when platform is at lowest point of travel.
(2) There shall be removable inspection plates on the worm gear housing for the purpose of inspecting the worm and gear. One plate shall be mounted adjacent to the mesh of the worm and gear, and one at the top of the gear housing.
(3) All machines shall be of winding drum type, arranged so that only one layer of wire rope is permitted. The drums shall be of cast iron or steel and have spiral finished U-grooves properly spaced for the cable size used. The worms, worm gear and spur gears shall have machine cut teeth. Cast iron for gearing material shall not be permitted. Tight fitting keys or splines shall be used for all connections subject to torque or tension. Only direct or geared couplings shall be provided between the speed reduction unit and hoisting drum.
(4) A primary brake shall be provided for normal stopping and holding of the platform. The primary brake shall be part of the driving machine assembly.
(5) A governor operated secondary brake shall be installed in addition to the primary brake. The governor operated secondary brake shall be one of the following types:
(a) Direct applied show brake either externally or internally consisting of two brake arms carrying pivoted brake shoes with suitable flexible brake lining and arranged to apply directly upon the drum or substantial integral extensions of the drum.
(b) A self-energizing band brake, externally applied to the drum or substantial integral extensions of the drum. The brake shall be constructed of high tensile steel band and lined with suitable flexible brake lining.
(c) A geared brake employing mechanisms which are wholly independent of the main service drive. The brake shall be of the brake shoe type, the main drum gear shall be directly attached to the drum through body fitted bolts. If an auxiliary drum gear is used in connection with the secondary geared brake, it shall also be directly attached to the drum through body fitted bolts. The geared brake may be applied to the main service drum gear providing this gear is of heavy duty construction with the American Gear Manufacturers Association publication A.G.M.A. 440.03 June, 1959, service factor of not less than 1.5 under conditions of maximum braking effect.
(6) Both the primary and secondary brakes shall be magnetically operated and spring set. Both brakes shall be arranged to operate on every stopping operation. In addition, the governor shall cause the secondary brake to set at 25 percent over speed independent of normal stopping devices. Each brake shall be capable of stopping and holding the rated load.
(7) All parts of the primary brake and of the secondary brake are to be readily accessible for the inspection and adjustment and shall be completely weather protected so that their function will be substantially the same under all weather conditions.
(8) A governor test shall be made with a capacity load on the platform to determine whether the secondary brake will stop and hold the main drum in the event the drum exceeds 25 percent above the rated speed.
(9) The diameter of drums and sheaves shall be 40 times the diameter of the hoisting ropes.
(10) All structural members shall have a minimum factor of safety of five. All other components of the hoisting machinery shall have a factor of safety, based on the total static load, of eight for wrought iron or wrought steel and 10 for cast iron, cast steel or other materials. Cast iron shall not be utilized in any load carrying capacity in the design of this equipment where it can be subjected to torsion, bending or tension.
(11) Safety factor for hoisting cables shall be not less than 10.
(12) The number and diameter of the cables shall be determined by using the required factor of safety and the rated ultimate strength of the cable. The computed load on the cables shall be the weight of the platform, plus its rated load, plus the weight of the hoisting cables. The minimum number of cables used shall be four. The minimum diameter of the cables shall be not less than 5/16 of an inch. Cables anchored to winding drums shall have not less than two complete turns of each cable on the winding drum when the platform has reached the limit of its travel.
(13) Winding drum machine shall have final stopping switches on the machine. Normal top and bottom terminal switches shall be provided.
(14) On 3-phase AC installations, the stopping switches on the machine shall be so arranged as to open the main line circuits to the motor and brake.
(15) Slack cable switches attached to the platform hitch shall be provided for each individual cable.
(g) Suspended working platform.
(1) The suspended working platform shall be fabricated of steel or aluminum or alloy of these basic structural metals.
(2) Design of the working platform shall be of the girder or truss construction and shall be adequate to support its rated load with a safety factor of eight.
(3) Welding, riveting and bolting of the platform members shall be in accordance with accepted practices.
(4) Platforms shall be suitably guided and shall be stable through its entire operation from top or bottom or vice versa. Engaging guide rollers or guide shoes shall be so designed to compensate for variation in building contour. Guide shoe brackets or casting shall be of a material that will resist shear and tensile loading. Cast iron shall not be used.
(5) All parts used in the construction or operation of the platform shall be fabricated from material that will consistently withstand severe local weather extremes.
(6) Platforms shall have a minimum net width of 24 inches and shall be furnished with permanent guard rails 36 inches high in the front (building side) and on the sides and 42 inches high in the rear. Guard interstices shall be filled with metallic mesh or similar material and shall reject a ball of 1 inch in diameter. If the platform is confined in its operation to a distance not exceeding 12 inches from the building, the mesh may be omitted on the front side, but a 4-inch toe guard along the front side must be provided. The platform flooring shall be of the nonskid type, open grating, which will reject a half-inch ball.
(7) The platform shall be fastened to the cables by individual tapered babbitted sockets, and the cable sockets and method of socketing shall comply with the requirements of this chapter. Each shackle shall be arranged for individual adjustment for cable tension.
(h) Ratings.
(1) The rated speed of the platform shall not exceed 50 feet per minute in the down direction with a fully loaded platform and shall not be less than 80 percent of the rated speed in the up direction with the same load.
(2) The rated capacity of the platform shall not exceed 25 pounds per square foot of platform area. The area shall be measured between the protection guards or toe guard and sides (ends) of the platform. Each platform shall bear a manufacturer’s rating plate stating the maximum permissible net load which shall be the sum of the allowable load of men, tools, materials.
(i) Roof car operating devices and control equipment. The roof car shall be rigidly constructed to withstand the unbalanced forces to which it will be subjected, and shall move on steel tracks securely fastened to the building structure.
(1) If the roof car is not parked in a roof garage, it shall be fully enclosed to protect the operating equipment placed on it from all weather extremes.
(2) The roof car, when power operated, shall have a drive independent of the driving units used for the platform.
(3) The control shall include constant pressure means to move the roof car forward or reverse, and a separate stop switch shall be available at the operating station to prevent all motion.
(4) The roof car shall not be movable unless the platform is out of its guides and in proper position on the roof car.
(5) Electric contacts or switches shall be provided and fastened to the building structure or roof car rails to indicate when the roof car is locked in proper place for placing of the platform in its guide.
(6) A power disconnect switch shall be permanently placed in roof car.
(j) Platform operating devices and control equipment.
(1) The control for the vertical travel of the platform shall be of the push button type and it shall be necessary to maintain a constant pressure on the "up" or "down" control button for operation. In addition, an emergency stop switch shall be provided which shall be of the positive open and close type. The control station and stop switch shall be permanently secured to one side guard of the platform and connected to the control panel through suitable rubber covered control cables.
(2) Where the platform length exceeds 20 feet, an auxiliary control station shall be located at the opposite side guard of the platform. This control station shall include a constant pressure type of "run" button which must be held closed while the platform is being moved.
(3) Communication equipment shall be provided for each powered platform for use in an emergency.
(4) All platform controls shall be so designed as to operate on a nominal voltage of 120.
(5) The controller for operation of the platform shall be installed in the roof car. It shall be fully enclosed for protection from the weather.
(6) Automatic tension control shall be provided for control cables attached to platforms. When the tension in the control cable exceeds a safe limit, electrical interlocking contacts shall remove power from the vertical traveling hoistway machines and brakes.
(Amend Coun. J. 4-10-19, p. 100029, Art. V, § 11)