- (a) Application. This section applies to movable platforms that are raised and lowered from the structure.
- (b) Hoisting of the platform shall be performed in a slow, controlled, cautious manner with no sudden movements of the platform.
- (c) Load and boom hoist drum brakes, swing brakes, and locking devices such as pawls or dogs shall be engaged when the occupied platform is in a stationary working position.
(d)
- (1) Portable towers shall be uniformly level within one percent (1%) of level grade and located on firm footing.
- (2) Portable towers shall be equipped with outriggers.
- (3) The outriggers shall be fully deployed following manufacturer's specifications when hoisting.
- (e) The total weight of the loaded platform and related rigging shall not exceed fifty percent (50%) of the rated load capacity for the radius and configuration of the portable tower.
(f)
- (1) The use of a machine having a boom in which lowering is controlled by a brake without aid from other devices which slow the lowering speed is prohibited.
- (2) Note. This type of prohibited boom is commonly called a live boom.
- (g) Portable towers with variable angle booms shall be equipped with a boom angle indicator, readily visible to the operator.
- (h) A positive-acting device, such as an anti-two-blocking device, shall be used to prevent contact between the load block or overhaul ball and the boom tip, or a system shall be used to deactivate the hoisting action before damage occurs in the event of a two-blocking situation.
(i)
- (1) The load-line hoist drum shall have a controlled-load lowering system or device on the power train, other than the load hoist brake, which regulates the lowering rate of speed of the hoist mechanism.
- (2) Free fall is prohibited.