Rigging And Ladder Safety Flashcards
What are the six considerations when choosing wire rope?
Strength
Flexibility
Resistance to abrasion
Resistance to crushing
Resistance to rotation
Resistance to corrosion
What are the 3 cores in wire rope?
Independent wire rope core IWRC- small diameter wire in the core of the main rope. IWRC increases resistance to crushing
Fibre core - core of wire is made of sisal, Manila, or other synthetic material. More flexible and increases elasticity.
Wire strand core- core is made of a single strand of wire. Not meant for lifting. Use for guy lines.
What type of core is better for conditions of elevated heat or freezing?
internal Wire core.
Fibre core will damaged with heat and freezing.
What is a sling?
Length of metal, natural fibre or synthetic fibre with various fittings or loops.
T = W/N x L/V is what formula ?
Sling stress formula.
If your sling lengths are not the same use the shortest sling length. This will give you a better safety factor
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T = tension per sling
W = weight in pounds
N = number of legs
L = choker length in feet
V = vertical load from hookup to load
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What advantages do web slings have over metal?
More flexible to go around lifting objects
The high elasticity minimizes shock and cushions the load
Light weight
Do not rust
Do not produce sparks
Resistant to spinning and twisting.
What is the SWL rule for nylon web?
1600 pound SWL per inch of width.
What is the criteria for broken wires in a running rope?
Signs of breakage in the valleys between the stands
Six or more broken wires in one rope lay
Three or more broken wires in one strand in one rope lay.
What is the criteria for replacing standing rope due to broken wires?
Replace standing rope if:
Three or more broken wires in one rope lay
Breaks near such starched fittings.
What does lay refer to?
The direction in which the strands of rope are twisted together
What are the 4 rope lays?
Left lay Lang lay
Right lay Lang lay
Right lay regular lay - most common
Left lay regular lay
What does lay length mean?
The distance along the rope a single strand makes one revolution.
What is the difference between regular lay and Lang lay?
In a regular lay the small strands are twisted together in one direction and then twisted around the core in the opposite direction.
Lang lay the single strands are twisted in the same direction as the strands twisted around the core.
What is an advantage of a nylon rope
Very strong
High elasticity
Good to use where shock loading is common
What is the benefits to poly rope?
Poly rope is cheaper then nylon
High buoyancy
Commonly used around water
Non conductor of electricity
When do you replace running rope?
Signs of breakage in the valleys
Six or more broken wires in one rope lay
Three or more broken wires in one strand of one rope lay
Why are shims needed for eye bolts?
To help align them
What is the formula for number of clips needed for wire rope?
Number of clips = rope diameter x 3 + 1
Clip spacing =?
Rope diameter x 6
Turn back equals?
Number of clips x spacing
When installing wire rope clips properly what is your rope strength percentage?
80 percent
How many tons will a 3/8 wire rope hold?
1 ton and each 1/8 added to 3/8’s will add an additional ton.
Example 1/2=3/8 + 1/8 = 2 ton(2000lbf)
How do you determine mechanical advantage when using block and tackle?
Count number of ropes on the travelling block.
7 ropes = 7:1
Why is chain not recommended for heavy lifting or impact loading?
A chain fails when one link breaks. Usually has little warning.
The very limited elasticity of chain does not handle shock loading.
