ing platform, excepting runways used exclusively for oiling, or running adjustments, shall be protected by a stationary casing enclosing shafting completely or by a trough enclosing sides and top or sides and bottom of shafting as location requires. (b) Wherever shafting extends over a driveway, it shall be protected as stated above unless it is located 15 feet or more above driveway. (c) Shafting under bench machines shall be enclosed by a stationary casing, or by a trough at sides and top or sides and bottom, as location requires. The sides of the trough shall come within at least 6 inches of the underside of table, or if shafting is located near floor, within 6 inches of floor. In every case the sides of the trough shall extend at least 2 inches beyond the shafting or protuberance. For requirements regarding materials and construction, see sections 50-204.179 and 50-204.181. § 50-204.159 Guarding vertical and inclined shafting. Vertical and inclined shafting 7 feet or less from floor or working platform, excepting maintenance runways, shall be enclosed with a stationary casing in accordance with requirements of sections 50-204.179 and 50-204.181. § 50-204.160 Projecting shaft ends. (a) Projecting shaft ends shall present a smooth edge and end and shall not project more than one-half the diameter of the shaft unless guarded by nonrotating caps or safety sleeves. (b) Unused key-ways shall be filled up or covered. § 50-204.161 Power-transmission apparatus located in basements. All mechanical power transmission apparatus located in basements, towers, and rooms used exclusively for power transmission equipment shall be guarded in accordance with these standards, except that the requirements for safeguarding belts, pulleys, and shafting may be omitted if the following conditions are met: (a) The basement, tower, or room occupied by transmission equipment is locked against unauthorized entrance. (b) The vertical clearance in passageways between the floor and power transmission beams, ceiling, or any other objects, is not less than 5 feet 6 inches. Any parts of which are 7 feet or less from the floor or working platform shall be guarded in accordance with the standards specified under section 50-204.179 and 50-204.181. Pulleys serving as balance wheels (e.g., punch presses) on which the point of contact between belt and pulley is more than 6 feet 6 inches from the floor or platform may be guarded with a disk covering the spokes. See section 50-204.180. § 50-204.163 Horizontal belts, ropes and chain drives. (a) Where both runs of horizontal belts are 7 feet or less from the floor level, the guard shall extend to at least fifteen inches above the belt or to a standard height (see table, section 50-204.181) except that where both runs of a horizontal belt are 42 inches or less from the floor, the belt shall be fully enclosed in accordance with sections 50-204.179 and 50-204.181. In power plants or power-development rooms, a guard rail may be used in lieu of the requirement in section 50-204.163. (b) Overhead horizontal belts, with lower part 7 feet or less from the floor or platform, shall be guarded on sides and bottom in accordance with section 50204.183. (c) Horizontal overhead belts more than 7 feet above floor or platform shall be guarded for their entire length under the following conditions: (1) If located over passageways or work places and traveling 1800 feet or more per minute. (2) If center to center distance between pulleys is 10 feet or more. (3) If belt is 8 inches or more in width. For detail of guard construction and for sizes of material see section 50-204.183 and table following section 50-204.184. (d) Where the upper and lower runs of horizontal belts are so located that passage of persons between them would be possible, the passage shall be either: (1) Completely barred by a guard rail or other barrier in accordance with sections 50-204.179 and 50-204.181, or (2) Where passage is regarded as necessary, there shall be a platform over the lower run guarded on either side by a railing completely filled in with wire mesh or other filler, or by a solid barrier. The upper run shall be so guarded as to prevent contact therewith either by the worker or by objects carried by him. In power plants, only the lower run of the belt need be guarded. § 50-204.164 Overhead chain and link belt drives. Overhead chain and link belt drives are governed by the same rules as overhead horizontal belts and shall be guarded in the same manner as belts (section 50-204.163). § 50-204.165 Vertical and inclined belts. (a) Vertical and inclined belts shall be enclosed by a guard conforming to standards in sections 50-204.179 and 50-204.181. (b) All guards for inclined belts shall be arranged in such a manner that a minimum clearance of 7 feet is maintained between belt and floor at any point outside of guard. Vertical belts running over a lower pulley more than 7 feet above floor or platform shall be guarded at the bottom in the same manner as horizontal overhead belts, if conditions are such as stated in section 50-204.163 (c) (1), (2), and (3). § 50-204.167 Cone-pulley belts. (a) The cone belt and pulley shall be equipped with a belt shifter so constructed as to guard adequately the nippoint of the belt and pulley. If the frame of the belt shifter does not adequately guard the nip-point of the belt and pulley, the nip-point shall be further protected by means of a vertical guard placed in front of the pulley and extending at least to the top of the largest step of the cone. (b) If the belt is of the endless type or laced with rawhide laces, and a belt shifter is not desired, the nip-point of the belt pulley shall be protected by a nip-point guard located in front of the cone extending at least to the top of the largest step of the cone, and formed to show the contour of the cone in order to give the nip-point of the belt and pulley the maximum protection. (c) If the cone is located less than 3 feet from the floor or working plat Gears shall be guarded in accordance with one of the following specifications: (a) A complete enclosure. (b) A standard guard as described in section 204.181 at least 7 feet high extending 6 inches above the mesh point of the gears. (c) By a band guard covering the face of the gear and having flanges extended inward beyond the root of the teeth on the exposed side or sides. Where any portion of the train of gears guarded by a band guard is less than 6 feet from the floor a disk guard or a complete enclosure to the height of 6 feet shall be required. § 50-204.169 Sprockets and chains. All sprocket wheels and chains shall be enclosed unless more than 7 feet above the floor or platform. Where the drive extends over other machines or working areas, protection against falling shall be provided. § 50-204.170 Openings for oiling. When frequent oiling must be made, openings with hinged or sliding selfclosing covers shall be provided. All points not readily accessible shall have oil feed tubes if lubricant is to be added while machinery is in motion. § 50-204.171 Friction drives. (a) The driving point of all friction drives when exposed to contact shall be guarded. (b) All arm or spoke friction drives and all web friction drives with holes in the web shall be entirely enclosed. (c) All projecting bolts on friction drives where exposed to contact shall be guarded. § 50-204.172 Keys, set screws, and other projections. All projecting keys, set screws and other projections in revolving parts shall be removed or made flush or guarded by metal covers. This does not apply to keys or set screws within gear or sprocket casings or other enclosures, nor to keys, set screws, or oil cups in hubs of pulleys less than twenty inches in diameter where they are within the plane of the rim of the pulley. All revolving collars, including split collars, shall be cylindrical, and screws or bolts used in collars shall not project beyond the largest periphery of the collar. § 50-204.174 Couplings. (a) Shaft couplings shall be so constructed as to present no hazard from bolts, nuts, set screws, or revolving surfaces. (b) Bolts, nuts, and set screws will, however, be permitted where they are covered with safety sleeves or where they are used parallel with the shafting and are countersunk or else do not extend beyond the flange of the coupling. GUARD STANDARDS FOR MECHANICAL (a) Standard conditions will be secured by the use of the following materials: Expanded metal, perforated or solid metal or wire mesh on a frame of angle iron or iron pipe securely fastened to floor or to frame of machine (see section 50-204.181). (1) All metal shall be free from burrs and sharp edges. (2) Wire mesh shall be of the type in which the wires are securely fastened at every cross point either by welding, soldering, or galvanizing, except in case of diamond or square wire mesh made of No. 14 gauge wire, 34 inch mesh or heavier. (b) Design of guards: (1) Where it is necessary to change belts, make adjustments or apply oil or grease, guards shall have hinged sections or be removable. (2) Guards shall be designed so as not to interfere with the usual machine operations, but give the maximum protection to the operator. (c) Methods of manufacture: (1) Filler material shall be expanded metal, sheet or perforated metal, or wire mesh and be securely fastened to frame. (2) By welding to frame every 4 inches. By weaving through channel or angle frame, or if No. 14 gauge 34 inch mesh or heavier is used, by bending entirely around rod frames. (3) Where openings in pipe railing are to be filled in with expanded metal, wire or sheet metal, the filler material shall be made into panels with rolled edges or bound with "V" or "U" edging of No. 24 gauge or heavier sheet metal fastened to the panels with bolts or rivets spaced not more than 5 inches center to center. The bound panels shall be fastened to the railing by sheet-metal clips spaced not more than 5 inches center to center. (4) Where the design of guards requires filled material of greater area than 12 square feet, additional frame members shall be provided to maintain panel area within this limit. (5) All joints of framework shall be made equivalent in strength to the material of the frame. (1) A shield guard shall consist of a frame filled in with wire mesh, expanded, perforated, or solid sheet metal. (2) If area of shield does not exceed 6 square feet the wire mesh or expanded metal may be fastened in a framework of % inch solid rod, 3⁄4 inch x 3⁄4 inch x 8 inch angle iron or metal construction of equivalent strength. (3) Metal shields may have edges entirely rolled around a % inch solid iron rod. All material of shield guard shall meet the requirements of section 50-204.181. (c) "U" Guards: A "U" guard consisting of a flat surface with edge members shall be designed to cover the under surface and lower edge of a belt, multiple chain, or rope drive. It shall be constructed of materials specified in table of section 50-204.181 and shall conform to the requirements of sections 50204.183 and 50-204.184. Edges shall be smooth, and if size of guard requires, these edges shall be reinforced by rolling, wiring, or by binding with angle or flat iron. above floor, or platform. (For the latter, see table following section 50-204.184.) § 50-204.181 Approved materials. (a) Minimum Requirements. The materials and dimensions specified in this section shall apply to all guards except horizonal overhead belts, rope, cable or chain guards more than 7 feet (b) Framework: (1) Minimum dimensions of material for the framework of all guards except as noted in subparagraph (5) of this paragraph shall be angle iron 1 inch x 1 inch x 8 inch, metal pipe of 3/4 inch inside diameter or metal construction of equivalent strength. (2) All guards shall be rigidly braced every 3 feet or fractional part of their height to some fixed part of machinery or building structure. Where guard is exposed to contact with moving equipment additional strength is necessary. (3) The framework for all guards fastened to floor or working platform and without other support or bracing shall consist of 12 inch x 11⁄2 inch x 8 inch angle iron, metal pipe or 11⁄2 inch inside diameter or metal construction of equivalent strength. All rectangular guards shall have at least 4 upright frame members each of which shall be carried to the floor and be securely fastened thereto. (4) Cylindrical guards shall have at least 3 supporting members carried to floor. (5) Guards thirty inches or less in height and with a total surface not in excess of ten square feet may have a framework of % inch solid rod, 34 inch x 3/4 inch x 8 inch angle or metal construction of equivalent strength. The filling material shall correspond to the requirements of the table contained in paragraph (a) of this section. (c) The specifications given in paragraphs (a) and (b) of this section are the minimum requirements; where guards are exposed to unusual wear, deterioration or impact, heavier material and construction shall be used to protect amply against the specific hazards involved. § 50-204.182 Wood guards. (a) Wood guards may be used in the woodworking and chemical industries, in industries where the presence of fumes or where manufacturing conditions would cause the rapid deterioration of metal guards; also in construction work and in locations outdoors where extreme cold or extreme heat makes metal guards and railings undesirable. In all other industries, wood guards will not be allowed. (b) Material and construction. (1) Wood shall be sound, tough, and free from any loose knots. (2) Guards shall be made of planed lumber not less than one inch rough board measure and edges and corners rounded off. (3) Wood guards shall be securely fastened together with wood screws, hard wood dowel pins, bolts, or rivets. (4) While no definite dimensions are given under this heading for framework or filler materials, wood guards shall be equal in strength and rigidity to metal guards specified in section 50204.181 (a) (b) (c). (5) For construction of standard wood railing, see section 50-204.185. § 50-204.183 Guards for horizontal overhead belts. (a) Guards for horizontal overhead belts shall run the entire length of the belt and follow the line of the pulley to the ceiling or be carried to the nearest wall, thus enclosing the belt effectively. Where belts are so located as to make it impracticable to carry the guard to wall or ceiling, construction of the guard shall be such as to enclose completely the top and bottom runs of belt and the face of pulleys. See section 50-204.163 (b) and (c). (b) The guard and all its supporting members shall be securely fastened to wall or ceiling by gimlet-point lag screws or through bolts. In case of masonry construction, expansion bolts shall be used. (c) Suitable reinforcement shall be provided for the ceiling rafters or overhead floor beams, where such is necessary, to sustain safely the weight and stress likely to be imposed by the guard. The interior surface of all guards, by which is meant the surface of the guard with which a belt will come in contact, shall be smooth and free from all projections of any character, except where construction demands it; protruding shallow round-head rivets may be used. Overhead belt guards shall be at least one-quarter wider than the belt which they protect, except that this clearance need not in any case exceed 6 inches on each side. Overhead rope drive and block and roller-chain-drive guards shall be not less than 6 inches wider than the drive on each side. In overhead silent chain-drive guards where the chain is held from lateral displacement on the sprockets, the side clearances required on drives of 20 inch centers or under shall not be less than 1/4 inch from the nearest moving chain part and on drives of over 20 inch centers a minimum of 2 inch from the nearest moving chain part. (d) The table following section 50204.184 gives sizes of materials to be used and general construction of guards for belts 10 inches or more in width. No material for overhead belt guards should be smaller than that specified in this table for belts 10 to 14 inches wide, even if the belt is less than 10 inches in width. However, No. 20 gauge sheet metal may be used as a filler on guards for belts less than 10 inches wide. Expanded metal, because of the sharp edges, shall not be used as a filler in horizontal belt guards. (e) For clearance between guards and belts, ropes or chains of various center to center dimensions between the shafts, see bottom of table following section 50-204.184. § 50-204.184 Guards for horizontal overhead rope and chain drives. Overhead-rope and chain-drive guard construction shall conform to section 50204.183 for overhead-belt guard construction of similar width, except that the filler materials shall be of the solid type as shown in table following section 50-204.181(a) unless the fire hazard demands the use of open construction. A side guard member of the same solid filling material shall be carried up in a vertical position 2 inches above the level of the lower run of the rope or chain drive and 2 inches within the periphery of the pulleys which the guard encloses thus forming a trough. These side filler members shall be reinforced on the edges with 12 inch x 14 inch flat steel, riveted to the filling material at not greater than 8 inch centers; the reinforcing strip shall be fastened or bolted to all guard supporting members with at least one % inch rivet or bolt at each intersection, and the ends shall be secured to the ceiling with lag screws or bolts. The filling materials shall be fastened to the framework of the guard and the filler supports by 3/16 inch rivets spaced on 4 inch centers. The width of the multiple drive shall be determined by measuring the distance from the outside of the first to the outside of the last rope or chain in the group accommodated by the pulley. |