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
~~~
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.
When is chain better suited?
Withstands rougher use
Does not kink easily
More resistant to abrasion
Less affected by high temperatures
How often should chains in regular use be inspected?
Once a month
How much wear is allowed before replacing?
Up to 10%
What is the stretch tolerance before replacing a chain?
Up to 3% stretch thoroughly inspect
Up to 5% replace
What is the only type of natural fibre rope to be used for lifting?
Grade 1 Manila
What is the SWL for fibre rope
5 to 1
What is the strength reduction of a knot?
50 %
What is the strength reduction of a bend?
50%
What is the strength reduction of a hitch?
25 %
What is the strength reduction of a splice?
15%
What is the cubic weight per foot of steel?
490lb/ft cubed
What is the cubic weight per foot of brass?
536lb/ft cubed
What is the formula for calculating rectangular block weights?
Volume=length x width x height.
Volume x density
What is the the formula for calculating a ring?
V= (3.14xRsquared xH) - (3.14xrsquared x H)
What is 5:1 rigging for?
General rigging and hoisting
What is 10:1 safety factor for?
Lifting and transporting workers
What is 20:1 safety factor for?
Public elevators
Wire rope Swl in tons =‘s
D2 x 8
Diameter squared
In Canada wire rope must not be used as temps at or above?
205 C (400f)
Wire rope termination efficiency chart
Maximum temperature nylon slings can be exposed to before being damaged?
82 C (180F)
Calculating sling angle factor is ____ button on your calculator?
WLL (basket) = WLL x number of legs x sling angle factor
Sin(sling angle)
Sin(60) = .866
Maximum capacity of a crane formula
Scaffolding must support at least_____ times the expected load
4 times
Sheave supporting wire rope should have ______ degree of support contact?
130 - 150 degree contact
Fleet angle for sheave winding is _____ degrees
1.5 degrees do not exceed 2 degrees
Chain wear for chains under 1” can be ___% and chains over 1” cab be ____%
5
10
Wedge sockets are only ____% of the maximum load
70 %
Swagged sockets are _____% efficiency
100%
If a thimble is not used on a eye the strength can be reduced by___%
10 %
True or false
Wire rope clips are right and left hand and must be installed on the correct wire rope?
True
Tapped hole for a lifting eye or bolt should be ____times the diameter?
1.5 times the diameter
Swl=swl(1) x H/L x number of legs
H = height from load to hook
L = length of slings
N = number of legs
Scaffolding height may not be taller than ____ it’s smallest dimension of its base
3 times
Guardrails must be installed on scaffolding when they are above_____ in height ?
How high must the horizontal rail be?
Above 3 meters
.92m to 1.07m
Toe boards must be a minimum height of______mm and must be installed when workers are working below when platform is ______ from the ground or floor?
140mm
3.5 m
Strand construction, see image
Measure wire rope _____ the amount of strands is how many different spots you measure.
1/2
Six strand rope check 3 spots
8 strand check 4 spots
Con of nylon slings
Affected by acids and bleaching agents. Degraded by UV radiation and exposure and degraded rapidly at temps above 200 degrees
Not affected by alcohol, alkalis, aldehydes and hydro carbons
Polyester sling
Less elasticity
Affected by alkalis (caustics), aldehydes (oxidated alcohols), degraded by high temps above 200f and degraded by uv
Some points for reeving wire rope blocks
. When the set of blocks has an equal number of sheaves, you must fast end of the rope to the stationary block becket.
• When the set of blocks has an unequal number of sheaves, you must fo dead end of the rope to becket on the block with the least sheaves.
• When the set of blocks has more than two sheaves, the lead line shoul from the sheave closest to the centre.
• The fixed block’s connection point should always be stronger than the the travelling block.
