437-007-0690 Metal Towers (1) A competent person must direct the raising and lowering of each metal tower. (2) All employees not engaged in the actual raising or lowering of metal towers must stay in the clear during these operations. (3) Metal towers must be level to provide proper line spooling and avoid excessive stress on component parts. (4) Each metal tower must have an identification plate permanently attached to its base or on the yarder in a position that can be easily read by a person standing on the ground or on the base platform. (5) All plates must contain the following information: (a) Name and address of manufacturer and model number; and (b) The maximum and minimum inclination at which the metal tower is designed to operate. (6) In addition, all identification plates on metal towers manufactured after July 1, 1980, must contain the following information: (a) The maximum breaking strength and size of mainline for which the metal tower is designed; (b) The maximum breaking strength and size of haulback line for which the metal tower is designed; (c) The number, minimum breaking strength and size of guylines or any other lines required; and (d) If the metal tower is designed for a skyline, slackline, or modified slackline system, the maximum breaking strength and size of skyline, mainline and haulback line that can be used. (7) All metal towers must be operated within the manufacturer's capacity: (a) As specified on the identification plate; or (b) As modified by the manufacturer; or (c) As designed and specified by a registered professional engineer. (8) If wire rope dimensionally larger in size or of a greater breaking strength than that specified by the yarder manufacturer is used for skyline, mainline, skidding line and/or haulback line, one of the following methods for limiting the load on the spar must be used: (a) A tamper-proof tension limiting device that automatically slacks the line loads (pull) on the metal tower to below its maximum identification plate rating. (b) A line fuse system installed in the skyline or mainline; or (c) Established operating procedures that limit line loads (pull) on the metal tower to below the maximum identification plate rating for the metal tower. (9) When a line fuse system is used to limit line loads (pull) on the metal tower: (a) The line fuse must have a designed breaking strength equal to or less than the maximum line rating of the metal tower as listed on its identification plate. (b) The line fuse must be certified and stamped as to the breaking strength. (c) The skyline or mainline must be hung in a single eye of the fuse link. (d) Notice must be given to crew personnel that line fuses are in use. (10) When operating procedures are used to limit line loads (pull) on the metal tower: (a) They must be observable or verifiable. (b) Any locking or dogging device on the brake or elsewhere must be removed or deactivated. (c) Personnel must be knowledgeable about the operating procedures that are in use to limit line loads. (11) Metal towers and their appurtenances must be inspected by a competent person each time the tower is lowered and at any time its safe condition is in doubt. (12) When damage from overstress or any other source is noted or suspected, the part in question must be inspected by a suitable method and found to be safe or the part repaired by a qualified person or replaced before the tower is again used. (13) Structural modifications or additions which affect the capacity or safe operation of metal towers must be made only under the direction of the manufacturer or a registered professional engineer. If such modifications or additions are made, the identification plate required in OAR 437-007-0690(4), (5) and (6) must reflect such changes. Statutory/Other Authority: ORS 654.025(2) & 656.726(4) Statutes/Other Implemented: ORS 654.001 - 654.295 History: OSHA 3-2004, f. & cert. ef. 6-7-04 OSHA 5-2003, f. 6-2-03, cert. ef. 12-1-03