Chapter 2 Flashcards
Rope Types
What are the common uses of rope in the electrical industry?
Pulling conductors, rigging applications, securing loads, or simply raising and lowering tools and material to workers on structures.
What is one of the most versatile and commonly utilized tools in the construction industry?
Rope
What is the OSHA Standard for rope use?
1926.251
What are the three most common rope types?
- Natural Fiber Ropes
- Synthetic Fiber Rope
- Wire Ropes
What is the ONLY Natural Fiber Rope that is able to be used for rigging purposes?
1 Grade Manilla
Why does Manilla Rope have limitations?
Its is subject to rot.
What happens when Manilla Rope gets wet?
- Shrinkage
- Loss of Strength
Prolonged sunlight exposure will also cause Manilla Rope to _________?
Deteriorate
OSHA requires Natural Fiber Ropes to be immediately removed from service if any of the following conditions exist:
- Abnormal Wear
- Powdered Fiber Between Strands
- Broken or Cut Fibers
- Variation in the size or roundness of strands
How are Synthetic Fiber Ropes made?
- They have individual fibers running their entire length.
- Fibers are wound on direction to make strands
- Strands are wound the opposite direction
What are some good properties Synthetic Fiber Ropes have?
- Has a high weight to strength ratio
- Absorbs very little moisture
- Does not stiffen when wet
- Has good dielectric properties when clean and dry
- Is resistant to damage caused by water and mildew
How much stronger is Synthetic Fiber Rope over Manilla Rope?
It can be 2-1/2 times stronger.
What are some other good properties of Synthetic Fiber Ropes?
They are lighter, easier to handle, and have excellent impact, fatigue and abrasion resistance.
What are Synthetic Ropes made of?
Nylon, polyester, polypropylene, and/or polyethylene either stranded or braided.
What are the properties of a stranded rope?
Made of larger cords of rope and has a bumpy surface
Why are braided ropes so much smoother than stranded ropes?
They are constructed with many smaller cords of rope and take on a woven look.
What are the characteristics if a typical three-stranded rope used in the utility industry?
- 1/2” Line
- 6.7 lbs per 100’
- Catalog Breaking Strength of 5,800 lbs
What are the advantages of braided synthetic ropes?
- Lower Weight
- Higher Strength
- Increased Durability
What are some properties of Duraplex?
- Each strand consists of a combination of polyester and olefin fibers giving it excellent weight to strength ratio.
- 1/2” line has a Catalog Breaking Strength (CBS) of 6,700 lbs.
What are some properties of Tenex?
- Made of Samthane coated polyester with excellent abrasion resistance and durability in addition to its high strength.
- 1/2” line has a Catalog Breaking Strength (CBS) of 11,800 lbs.
What are some limitations that Synthetic Fiber Ropes have?
- Strands will melt subject to heat.
- Can be damaged by sharp edges or abrasion when under tension.
What are OSHA’s requirements for removal of Synthetic Fiber Rope?
- Abnormal Wear
- Powdered Fiber Between Strands
- Broken or Cut Fibers
- Variation in the Size or Roundness of Strands
What are the primary uses of using wire rope in the power delivery industry?
- Heavy Duty Rigging Slings
- Hoist Lines for Cranes
- Hoisting Large Heavy Loads
What are the three basic grades of wire rope made of steel?
- Mild Plow Steel Wire Rope
- Plow Steel Wire Rope
- Improved Plow Steel Wire Rope
When should wire ropes be avoided?
Any work involving energized conductors and apparatus.
What is wire rope subject to?
- Rust erosion in the center of the wire rope
- Kinks or Bends
What is some good maintenance of rope?
- Ropes should be clean and dry when stored.
- Ropes should be hung in neat coils devoid of kinks or twists
- Splinter, thorns, burrs, sand, and gravel should be removed at every opportunity
- Avoid contact with chemicals that may weaken the strength of the rope
What is CBS?
- Catalog Breaking Strength
- The average force in pounds needed to break a rope
What is WLL?
- Working Load Limit
- The maximum load that should ever be applied to a rope
What is WLL sometimes referred to as?
- Safe Working Load (SWL)
- Maximum Load Value
- Rated Capacity
What fraction or percentage is the WLL of the CBS?
One-Fifth (1/5) or 20%
What is the number used to calculate the WLL of a rope?
- Design Factor
- Industry Standard is 5
What are the equations for calculating WLL?
- WLL = CBS / 5
- WLL = CBS divided by 5
- WLL = CBS x .2
What is the weakest point of a rope?
Knots and Splices
What is Dynamic Loading?
Dynamic Loading occurs when ropes are subject to severe exposure conditions.
What are some examples of Dynamic Loading?
- Shock Loading
- Excessive Use
- Exposure to High Temperatures
- Extended Periods Under Load
