STSC Cranes, Derricks, Hoists, and Rigging Safety 5

Question 1

What is the required action when a crane is to be used for a 'critical lift' as defined under OSHA 1926.1431?

Accepted Answer

Prepare and follow a written critical lift plan

Answer

OSHA 1926.1431 requires a written critical lift plan for lifts exceeding 75% of the crane's rated capacity or involving multiple cranes.

Question 2

A load is being rigged with a choker hitch. Compared to a straight (vertical) hitch with the same sling, how does the choker hitch affect the working load limit?

Accepted Answer

It reduces the WLL because the choker creates a pinch point and angle loading

Answer

A choker hitch reduces the sling's rated capacity, typically to about 75-80% of straight-hitch WLL, due to stress concentration at the choke point.

Question 3

Under OSHA crane standards, what is the maximum wind speed at which a crane operator is typically allowed to continue operations with a rated load?

Accepted Answer

There is no OSHA wind speed limit; the manufacturer's specifications govern

Answer

OSHA defers to the crane manufacturer's load chart and operational specifications for wind speed limits rather than setting a universal mph threshold.

Question 4

What condition requires a wire rope to be removed from service per ASME B30.5 if found in any six-diameter length of the rope?

Accepted Answer

Six randomly distributed broken wires

Answer

ASME B30.5 requires removal from service if six or more randomly distributed broken wires are found in any six-rope-diameter length.

Question 5

When using a jib or luffer attachment on a crane, what additional concern must the rigger and operator account for in the load chart?

Accepted Answer

Load charts change with jib length and angle; a separate jib chart must be used

Answer

Jib attachments have separate rated capacity charts that account for the additional boom length, radius changes, and structural loading on the main boom.

(STSC) Safety Trained Supervisor Construction Practice Test

(STSC) Safety Trained Supervisor Construction Practice Test

STSC Cranes, Derricks, Hoists, and Rigging Safety 5