By H-Lift | 05 January 2023 | 0 Comments
What is Factor of Safety (FoS) ?
In engineering, a factor of safety (FoS), also known as (and used interchangeably with) safety factor (SF), expresses how much stronger a system is than it needs to be for an intended load. Safety factors are often calculated using detailed analysis because comprehensive testing is impractical on many projects, such as bridges and buildings, but the structure's ability to carry a load must be determined to a reasonable accuracy.
Good practice requires that any lifting equipment shall have an adequate factor of safety incorporated in its design. Where appropriate in each of the separate sections, a minimum factor of safety for the specific item is recommended and this should not be reduced.
The purposes of a factor of safety are numerous, including allowance for wear, impact, dynamic loading and accidental overloading. For example, chain slings are more robust and defects can be more apparent than textile slings and therefore tend to have a lower factor of safety. However, it cannot be too highly stressed that such allowances are a contingency only and must never be purposely eroded. Care should always be taken to avoid circumstances which can overload (e.g. impact, shock) and care should also be taken in circumstances where inadvertent overload can occur (e.g. multi point lifts. ). In extreme cases, where several adverse circumstances occur at the same time, the result may be failure even though the nominal load lifted does not exceed the SWL of the equipment. If such circumstances are likely to occur, reference should be made to a Competent Person who will advise whether it is necessary to use higher rated equipment to achieve
a higher factor of safety.
Good practice requires that any lifting equipment shall have an adequate factor of safety incorporated in its design. Where appropriate in each of the separate sections, a minimum factor of safety for the specific item is recommended and this should not be reduced.
The purposes of a factor of safety are numerous, including allowance for wear, impact, dynamic loading and accidental overloading. For example, chain slings are more robust and defects can be more apparent than textile slings and therefore tend to have a lower factor of safety. However, it cannot be too highly stressed that such allowances are a contingency only and must never be purposely eroded. Care should always be taken to avoid circumstances which can overload (e.g. impact, shock) and care should also be taken in circumstances where inadvertent overload can occur (e.g. multi point lifts. ). In extreme cases, where several adverse circumstances occur at the same time, the result may be failure even though the nominal load lifted does not exceed the SWL of the equipment. If such circumstances are likely to occur, reference should be made to a Competent Person who will advise whether it is necessary to use higher rated equipment to achieve
a higher factor of safety.
How often should lifting equipments be subject to thorough examantions?
What is a Safe Working Load ( SWL ) ?
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