RIG CH.2 Flashcards
What does OSHA standard 1926.251 apply too?
The use and care of ropes
What are the three most common types of rope?
Natural fiber, synthetic fiber ropes and wire ropes
What is the main natural fiber rope used for rigging?
1 Grade Manila
What is the main limitation of Manila rope?
it is subject to rot
What are some other limitations of manila rope besides rot?
Shrinks and loses strength when wet
If you had the option between manila rope or synthetic rope which would you use?
Synthetic
What conditions present on natural fiber rope would remove the rope from service immediately?
Abnormal wear, Powdered fiber between strands, broken or cut fibers, and variation in the size or roundness of strands
What characteristic does the fibers on synthetic rope have?
Fibers run the entire length of the rope
How are fibers wound?
Fibers are wound in one direction and strands are wound in the opposite direction.
What are some key characteristics of synthetic rope?
High weight to strength ratio, absorbs very little moisture, does not stiffen when wet, has good dielectric properties when clean and dry, resistant to damage caused by water and mildew
How much stronger can synthetic rope be than manila rope, of the same diameter?
2.5 times stronger
What are some common materials that synthetic ropes are made from?
nylon, polyester, polypropylene, and/or polyethylene
What characteristics are typical of a three-stranded synthetic rope used in the utility industry?
1/2 inch line, 6.7 pounds per 100 feet, and a catalog breaking strength of 5800 pounds
What are the OSHA requirements for removal of synthetic rope?
Same as natural fiber rope, abnormal wear, powdered fiber between strands, broken or cut fibers, variation in the size or roundness of strands
What is the strongest of the wire ropes?
Improved plow steel wire rope
What are the primary uses for wire rope?
heavy duty rigging slings and hoist lines for cranes
What are the three basic grades for wire rope?
mild plow, plow, and improved plow steel wire rope
When should the use of wire rope be avoided?
When working around energized conductors and apparatus
Many companies will have you discard wire rope if this condition is present.
Any of the wires are broken
Regardless of what type of rope, what condition should all ropes be kept as?
All rope should be kept as clean as possible
What is the minimum proper care that all ropes should have?
Ropes should be clean and dry when stored, ropes should be hung in neat coils devoid of kinks or twists, avoid contact with chemicals that may weaken the strength of the rope, remove the following at every opportunity: splinters, thorns, burrs, sand, and gravel
Define Catalog Breaking Strength (CBS)
The average force needed to break a rope
T or F: Ropes should be subjected to tensions approaching the CBS
False
Define Working Load Limit (WLL)
The maximum load that should ever be applied to a rope
What are some other names for the working load limit?
Safe working load, maximum load value, and rated capacity.
T or F: The working load limit is always less than the catalog breaking strength.
True
What is the industry standard on how much less should the WLL be than the CBS?
one-fifth or 20% of the CBS
T or F: When using ropes it is okay to regularly exceed the WLL as long as it is under the CBS.
False
What is the Design Factor?
Design Factor is an arbitrary number used for calculating WLL. CBS is divided by Design Factor to determine WLL.
What is the weakest point of a rope?
At the knot or splice
What is the calculation for WLL?
WLL = CBS / Design Factor
What is dynamic loading?
Dynamic loading is when ropes are subject to severe exposure conditions
What are some examples of dynamic loading?
shock loading, excessive use, exposure to high temps, and extended periods under load
