Chain blocks are an essential material handling tool used to lift and move heavy loads up to several tons across manufacturing, warehousing, construction and other industries. However, if the load capacity is exceeded or components fail, a chain block failure could result in dangerous falling loads.
Using chain blocks with the appropriate design safety factor minimizes this risk by building in extra load capacity cushion. In this blog, we’ll look at how safety factor protects against chain block failure, how it’s calculated, and considerations for achieving optimal safety.
The Role Of Safety Factor
Safety factor is a key chain block specification that ensures the equipment can support much heavier loads than its rated capacity safely. For example, a 1 ton chain block with a 5:1 safety factor can actually withstand loads up to 5 tons without failing structurally.
This redundancy protects workers in case:
- Load weight is underestimated or heavier than expected
- Load is improperly balanced or shifts suddenly
- Wear and tear reduces strength over time
- A defective component or weakness exists
- Equipment is misused or handled roughly
The higher the safety factor, the more “buffer” exists to prevent overloading and potential catastrophic failure even in non-ideal conditions.
Calculating Chain Block Safety Factor
Safety factor is calculated by dividing the breaking strength of a chain block by its working load limit or rated capacity.
For example, if a 1 ton capacity block has a breaking strength of 8 tons, its safety factor is 8/1 = 8:1. Ideally, all elements are overdesigned to maximize equipment integrity.
Key variables that influence the ultimate safety factor include:
- Load chain size, grade, and composition
- Hook, pulley, and wheel design and durability
- Strength of welds, hitches, and mechanical components
- Quality control in manufacturing and assembly
Factors To Consider
When selecting chain blocks, consider these factors regarding safety:
- Look for a minimum 5:1 safety factor or higher. Up to 10:1 is preferable for hazardous loads.
- Ensure safety factor is validated through stringent proof load testing.
- Choose reputable manufacturers with robust design, testing and inspection processes.
- Buy chain blocks certified to meet the latest ASME and OSHA standards.
- Examine construction thoroughly checking for quality welds, fasteners, castings and machining.