Lifting using Accessories
Calculation of Load
- There are only two types of load to be lifted
- Known- there must be a Certificate of Weight or a Guaranteed Weight name plate attached.
- Estimated- Any other weight. When doing lift calculations 50% must be added to estimated weight
Safe Working Loads
For a straight vertical lift the maximum lift weight is the Safe Working Load (SWL) of the lifting accessoryFor a lift using an accessory with two legs or two matched pairs used at angles up to 45o from vertical ( i.e. non vertical to 90o included) then the maximum SWL is 1.4 (normally rounded up to 1.5) times the SWL in each leg e.g. the maximum lift for two matched 5 tonne strops is 7.4 tonnesThe maximum included angle is 90o, no lift should take place with angles greater than this.
The maximum included angle is 90o
Note
- For lifting accessories such as Multileg chain slings (�Brothers�), the SWL takes in to account that may be used at angles up to 45o and therefore the maximum lift weight would be the SWL of each leg times the number of legs ( or stated Total Lift) although this should be clear stated on Test Certificate.
- The reduction in capability also applies to Shackles used when used in non vertical Lifts ( Dee Shackles must only be used in vertical lifts)
- The reduction in capability also applies to Chain blocks, lever hoists which are in use.
- For non uniform shaped loads special consideration has to be given to the Centre of Gravity and possible localised overloading.