One particular example that needs attention is precast stair flights.

The lifting insert is often positioned on the tread surface as shown here.  In this case, the U bar has to extend down to the reinforcement in the bottom face of the waist.  If this is not done, then there is a risk of the top surface of the tread breaking out.  Better still is to reinforce the tread locally so as to prevent the nose of the tread failing if the lift creates inclined forces.   A straight bar, running horizontally along the tread, should not be used. 

If non-vertical loads are anticipated, particularly near the end of a unit, then additional, inclined, bars should be added to resist the loads as shown.   The open end of the bars should always point away from the direction of the force.

Plate anchor

These are frequently used in thin/flat slabs.  Again they are mainly used for vertical lifting, although, unlike most inserts, they also have full capacity for transverse lifts.

Reinforcement is placed on top of the plate, and for larger sizes is in both directions as shown. 

Most suppliers give recommendations for the shape of the bars along the lines of the sketch below. These are only guidelines however, and two main points need to be considered. 

For small size inserts, the bars are close to the top surface.  For example, for an Rd12 insert the top of the bar may be only 21mm from the top surface.  This may cause problems clashing with any reinforcement in the top 50mm or so of the unit.  Similarly, for a larger size of insert, the reinforcement shown may extend down some 185mm from the top surface, and this could clash with bottom reinforcement.  To avoid this, an accurate drawing should be created.