Rigging and Hoisting Operations Flashcards

A rigging plan requires lifting a 1,200 lb antenna using a two-leg bridle sling. The length of each sling leg (L) is 10 feet, and the vertical height from the load to the hook (H) is 7 feet. What is the approximate tension on each sling leg?

Answer: 857 lbs

The tension on each sling leg is calculated by first finding the load per leg if it were a vertical lift (1,200 lbs / 2 legs = 600 lbs). Then, calculate the load factor, which is the sling length (L) divided by the height (H) (10 / 7 ≈ 1.428). Finally, multiply the vertical load per leg by the load factor (600 lbs * 1.428 ≈ 857 lbs). As the angle between the slings decreases, the tension on each leg increases significantly.

When operating a capstan hoist to lift materials, what is the primary reason for maintaining a specific number of wraps on the drum and applying tension to the fall line?

Answer: To create sufficient friction for the hoist to grip the rope and manage the load

A capstan hoist does not store the rope on the drum like a winch. It works by using the friction between the rope and the rotating drum (capstan head). The operator must maintain the correct number of wraps and apply tension to the non-load-bearing end of the rope (the fall line) to create enough friction for the drum to grip the rope and move the load.

Which of the following standards, developed jointly by the Telecommunications Industry Association (TIA) and the American Society of Safety Professionals (ASSP), specifically addresses the 'means and methods' of construction and safety practices for communication structures?

Answer: ANSI/ASSP A10.48

ANSI/ASSP A10.48, 'Criteria for Safety Practices with the Construction, Demolition, Modification and Maintenance of Communications Structures,' is the standard that focuses on the safety of tower workers, covering the means and methods to be employed during work. ANSI/TIA-322 covers the engineering, design, and loading analysis, while TIA-222 is the structural standard for the towers themselves.

A gin pole is being used to lift a new tower section. Which component of the gin pole assembly is primarily responsible for attaching the entire apparatus to the existing tower structure?

Answer: The clamp assembly

A gin pole consists of three basic parts: a pole (mast), a pulley assembly (rooster head/load block), and the clamp assembly. The clamp assembly is what physically secures the gin pole to the leg or a structural member of the tower, providing the foundation for the lift.

When inspecting rigging equipment before a lift, a technician discovers a wire rope sling with 'birdcaging'. What is the correct course of action?

Answer: Remove the sling from service immediately

Birdcaging is a form of distortion in a wire rope where the strands untwist and separate, creating a cage-like appearance. This indicates core failure or shock loading and severely compromises the rope's strength. Any rigging equipment showing signs of kinking, crushing, or birdcaging must be immediately removed from service and destroyed to prevent accidental reuse.

According to OSHA directives regarding hoisting personnel on communication towers, if a hoist has a maximum rated load capacity of 2,000 lbs for materials, what is its maximum load capacity when used for lifting personnel?

Answer: 1,000 lbs

OSHA directive CPL 02-01-056 specifies that when hoisting personnel, the hoist's specified rated capacity must be de-rated by a factor of 2 (reduced by half). Therefore, a hoist rated for 2,000 lbs for materials would have a personnel load capacity of 1,000 lbs. This provides an increased safety factor for lifting people.