When making a lift, one of the first things we should consider is the angle of our rigging, whether it be cable, nylon slings, chains, or anything else. The angle of the rigging can reduce the capacity of the rigging being used due to tension. If we are using a two-leg bridle while lifting a manhole for instance, the wider the rigging is attached, the the less the rigging can lift and could cause damage to either the rigging or the manhole in this particular case.
A 30-degree angle will lift less than a 60-degree angle, and it also depends on the length of the rigging that is being used. Calculating rigging angles is important, and at Western Precast, we practice rigging angle calculations daily, and its always good to update ourselves and riggers, knowing what angles are safe to use when making a lift.