Lifting attachment design factors

[leon25034796]

I'm looking for some advice:
I am trying to determine the allowable stress in a lifting attachment we have had manufactured. The lifting attachment is a mild steel block that bolts to the component to be lifted with a lug to enable a shackle to be fitted; two of these blocks are then fitted to the component at either end and the component is then lifted by crane.
When calculating the stresses in the component I have multiplied the load by 1.3 for a dynamic load factor. What I am trying to determine is the allowable stress i.e. FOS required. I have had a scan through BS2573, BS5950, BS449.
BS2573 seems the simplest to follow and I believe BS5950 is a plastic code where I am interested in elastic. However is BS2573 applicable to lifting attachments as it seems predominantly concerned with cranes?

 

[nvn]

leon25034796: I am not familiar with those cited standards, but I seem to recall that, for lifting attachment hardware, you typically use a yield factor of safety of 3.0, and an ultimate factor of safety of 5.0.