RopeLab Quiz 3: Factors of Safety

A quick quiz to test your understanding of the true implication of the term ‘Factor of Safety’.  There are 6 multiple choice questions.  To do this quiz you’ll need to forget about what SF you normally use.  Just answer each question.

The scenario assumes a site safety officer (not a rope specialist) walks up, looks at your system and asks what Factor of Safety you think you have.  In other words: How many times over could the system support the current load before you expect it to fail?

Hint: go through each element and determine the force at which it may fail.  For example, if the weakest element may fail at 9kN and the applied load is 3kN then the Factor of Safety is 3.

Make sure you read the assumptions stated in this image:

 

All of the images in this quiz have been created using vRigger (see http://www.vRigger.com for details).

© Richard Delaney, RopeLab 2015.

1. Question 1: Single Rope

What is the Factor of Safety for the setup shown below?

The 3kN load is supported by a single strand of knotted rope.

SF1

2. Question 2: Double Rope

What is the Factor of Safety?

The 3kN load is supported by a double strand of knotted rope.  Assume that the load is shared equally by the two ropes.

SF2

3. Question 3: Double Rope Tie-in

What is the Factor of Safety?

The 3kN load is supported by a double strand of knotted rope but tied directly to the load.  Assume that the load is shared equally by the two ropes.

SF3

4. Question 4: Single Rope Y-hang

What is the Factor of Safety?

The 3kN load is supported by a single strand of knotted rope.

SF4

5. Question 5: Single Rope Overhead Pulley

What is the Factor of Safety?

The 3kN load is supported by a single strand of knotted rope which runs up through an overhead pulley and back down to a ground anchor.

SF5

6. Question 6: Single Rope Double Overhead Pulleys

What is the Factor of Safety?

The 3kN load is supported by a single strand of knotted rope which runs through two overhead pulleys and back down to a ground anchor.

SF6

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