You are calculating the load capacity for a mobile crane. The crane chart shows a capacity of 15,000 pounds at a 20-foot radius. If you need to lift a load weighing 12,000 pounds including rigging, what is the safety factor being applied?
Correct Answer
B) 1.25
The safety factor is calculated by dividing the crane capacity by the actual load: 15,000 ÷ 12,000 = 1.25. This provides a 25% safety margin above the actual load weight.
Why This Is the Correct Answer
The safety factor is calculated by dividing the crane's rated capacity by the actual load weight being lifted. In this case, the crane has a capacity of 15,000 pounds at 20-foot radius, and the load weighs 12,000 pounds including rigging. The calculation is 15,000 ÷ 12,000 = 1.25, which means the crane capacity is 1.25 times greater than the load, providing a 25% safety margin.
Why the Other Options Are Wrong
Option A: 1.15
1.15 would result from incorrect calculation or using wrong values. This would only provide a 15% safety margin, which is insufficient for crane operations.
Option C: 1.33
1.33 would result from reversing the calculation or using incorrect values. This would suggest a 33% safety margin, which while conservative, is not what the given numbers produce.
Option D: 1.20
1.20 would result from incorrect calculation. This would only provide a 20% safety margin, which doesn't match the actual relationship between 15,000 and 12,000 pounds.
Memory Technique
Remember 'Big over Little' - the bigger capacity number goes over the littler load number when calculating safety factor.
Reference Hint
Look up crane safety and rigging sections in construction safety manuals or OSHA 1926 Subpart CC - Cranes and Derricks in Construction
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
A detail drawing shows a scale of 3/4" = 1'-0". If a dimension measures 2.25 inches on the drawing, what is the actual dimension?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass
Previous Question
A excavator with a 2.5 cubic yard bucket is loading trucks for a site cut operation. If the bucket has an 80% fill factor and the soil has a 25% swell factor, what is the actual volume of in-place soil moved per bucket load?
Next Question
What is the recommended maximum spacing for drywall screws when attaching 1/2" drywall to wood studs?