Rigging Basics Flashcards
What does proper rigging reduce?
The risk of personal injury and prevents damage to equipment, and make the most strenuous lifting tasks relatively easy.
What is a rope?
A group of fibers or strands which are twisted or braided together in order to combine them into a larger and stronger form.
What are the two broad fiber rope groups?
- Natural fibers
- Synthetic fibers
What are the most common rope types used by SCE Linemen?
Combination Polyester and Polypropylene
What are cotton ropes are generally used for?
A backup, or in addition to, synthetic ropes. Also used for a wide variety of low weight/low consequence applications.
What does a rope’s diameter determine?
It’s Working Load Limit (WLL)
How do you determine WLL?
Breaking Strength divided by Safety Factor
Generally, what size ropes are synthetic ropes?
1/2” and 3/4”
What size rope is most commonly used for handlines?
1/2”
What is a common name for 3/4” rope?
Bull Line
What size is Cotton Line typically?
3/8”
What size rope is used for truck sand lines?
7/8”
What would shorten the lifespan considerably of fiber rope?
Improper Care
How do you prolong the life and strength of fiber rope?
- Ensure that rope is dry and stored in a cool dry space.
- Coil it in a spool or hang it from pegs in a way that allows air circulation
What should you avoid doing with rope?
- Dragging it through sand or dirt or pulling it over sharp edges. Sand or grit between fiber cuts the and reduces the rope’s strength.
- Exposure to excessive heat and fumes from chemicals; heat or boiling water decreases rope strength by about 20%
If a rope becomes wet, what should it be considered as?
A conductor
What qualities does a good knot have?
- The right knot for the application
- Easy to tie
- Does not overly compromise the strength of the rope
- Is easy to untie
What are the eight rigging knots?
- Square knot
- Half Hitch/Two Half Hitches
- Bowline
- Bowline on a Bight
- Clove Hitch
- Timber Hitch
- Eye Splice
- Short/Butt Splice
What does tying a knot do to a rope?
Decrease the strength of the rope
What is a rule of thumb to remember about knot deficiency ratings?
A knot reduces its efficiency by 40%-50%
What is a rule of thumb to remember about splice deficiency ratings?
A splice reduces its efficiency by 10%-15%
What is the efficiency rating of an Eye Splice?
45%
What is the efficiency rating of a Short Splice?
80%
What is the efficiency rating of a Timber Hitch or Half Hitch?
65%
What is the efficiency rating of a Bowline or Clove Hitch?
60%
What is the efficiency rating of a Square Knot or Sheet Bend?
50%
What is the efficiency rating of a Overhand Knot?
45%
Before any rigging evolution, what must you determine first?
Total Weight
What do you need to know in a rigging evolution?
- Total Weight
- WLL for all equipment, tackle, ropes and knots
What are some commonly used rigging equipment?
- Wire pulling grips
- Hoists
- Slings
- Shackles
- Blocks and Tackles
- Handlines
What must be used when the angle of pull is changed?
A Sheave
What is the Handline Sheave rated for?
1000 lbs
What is the Handline Hook rated for?
1000 lbs
What is the 2” Ring rated for?
900 lbs
What is the Handline Snap rated for?
750 lbs
What is the 1/2” Rope (with eye splice) rated for?
315 lbs
What do you always use when raising and lowering tools and equipment?
A Nosebag
What are the main uses of a handline?
- To raise and lower tools and material
- As a tag line to pull bulky apparatus away from a pole
- As a throw line
- Most importantly, Hurt Man Rescue
What are Tackle Blocks known as?
Set of Fours
What are Tackle Blocks used for?
To add mechanical advantage to a rigging task
What does friction do when running through sheaves?
Mechanical advantage is reduced by 10% through each sheave
What does two blocked mean?
When the moving block does not have enough line to travel the needed distance and is stopped at the stationary block
What does making sure the blocks are straight and in line do?
Minimize excess friction and weak load angles, while ensuring lines are able to provide their full strength to the task.
What are hoists used for?
To provide mechanical advantage in pulling, lifting and lowering tasks.
What do hoists require?
A straight line pull
How are hoists geared?
To “pull in,” “let out,” and “freewheel”
How do you connect the hoist to the load?
Hooks, slings and chokers
What are some basic operating guidelines?
- Remove twists from the load chain (or strap) and the hand chain (or strap)
- Lift with the hoist directly over the load, with both hooks free to swivel
- Never hook the chain (or strap) onto itself
What are slings used for?
To connect the load to the rigging system
What can you find on the manufacturer’s tag of a sling?
WLL ratings for different configurations
What should you do if the manufacturer’s tag is missing?
The sling cannot be used if the tag is missing or illegible.
What are the three configurations when using a sling?
- Straight-Line Hitch
- Basket Hitch
- Choker Hitch
What should be used when using the sling in a choke?
Shackles
What’s another name for a wire pulling sock?
Kellum Grip
What’s a wire pulling sock used for?
To pull conductor across long spans
What is a Kellum grip?
Wire mesh “sock” that tightens on the conductor end
What is important to insert between the eye of the Kellum grip and the pulling device?
Swivel
What is the basic method that should be followed when rigging?
- ) Initial Consideration
- ) Selection
- ) Hitching Equipment
- ) Moving the Load
What is Initial Consideration?
The overall rigging task is assessed: distances, angles, obstructions, and the environment are considered. Collecting as much information as possible during this step, allows easier and more accurate decisions to be made later on.
What is Rigging Selection?
The equipment and materials to be used are selected. The information gathered in the first step is used as the criteria in this step. Once the rigging equipment and materials are selected, then all of the WLL’s can be determined and the rigging calculations may be performed. Remember, the load weight may not exceed the WLL of the component with the lowest value.
What is Rigging Installation?
The rigging is installed and connected (using slings or shackles) to the load. While installing rigging, ensure that all the applicable RSM guidelines are followed.
What is Moving the Load?
All of the planning, calculations, equipment and materials are put to use. While moving the load, everyone involved with the task must remain vigilant and observant. Each person should be looking for any problems that might appear, maintaining positive control of their equipment, and communicating effectively with those involved.
