Rank: Forum user 
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I am in some debate with an erection contractor on site as to the safety factor of load to be lifted.
The load is 30 ton; a load test was carried out, as well as the load having clear 30 ton markings.
My question is; what safety factor should be assigned to the lifting equipment?. I am of the opinion it should be + 25% of the load weight and lifting tackle.
Can someone on the forum provide information on this matter?
Thanking you in advance
Paul
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Rank: Forum user
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Hi, Not my area of expertise but I believe the factor of safety is calculated by dividing the breaking load by the safe working load and in factories it was 6 and docks it was 5 for wire rope. However I can recommend a really good pocket guide 'The International Rigging and Lifting Handbook' by North Sea Lifting at www.nsl-aberdeen.com, it contains a wealth of info fits in your pocket and isn't (or wasn't) expensive. Regards Steve
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Rank: Forum user
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Thank you Stephen.
Just having a look at the website.
Gathering all information on this matter.
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Rank: Super forum user
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If you know the Load is 30 ton then lifting equipment rated to 30 tons would be fine. All lifting equipment has it's own safety factors built in for strops it's something like 5 times the rated lift capacity.
can't see an issue if you having lifting equipment rated to the weight they are going to lift especially if you know the weight which in most cases you don't so you would then over rate the lifting equipment to allow for any error in you calculations of the weight of the object.
Phil
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Rank: Super forum user
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(Can't believe you can't edit on this forum)
How you sling the weight may have an effect on the rating of the slings if you use say 3 slings to lift the weight on sling will/may be carrying more weight than the other two. ideally you should have a lift plan especially given the weight of the item. If you are liftying with more than one sling then yes you might need to rate the slings higher
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Rank: Forum user 
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Totally agree with Phil. If the weight is calculated then the 20% FoS comes into play, however with a known and proved weight there is no requirement for an extra FoS above the one included within the accessories. Also in agreement with Phil that the sling/chain angles will require calculation to ensure that they still fall within the correct SWL as this is determined at a lift in a vertical plane.
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Rank: Forum user
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Thank you Phil + Walkera.
We do have a lift plan / plot plan for the lift scheduled to commence on Sunday.
We have riggers / slingers - signallers on site that look after the lifting equipment.
I understand the differences in lifting loads with 1 -2 -3 -4 point lifts.
This lift will be undertaken from rated lifting points on the load, riggers wll be using chains / shackles / lifting hooks.
Thank you once again for your advice on this matter.
Paul
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