Buffer Zone [2]

A distance and area in between that is maintained between an operative and a feature, property, people, or animals, whilst carrying out grounds maintenance work, especially whilst using machinery.

This is to ensure the safety of the operator as well as surroundings, helping to reduce the likelihood of any flying debris hitting an object or injuring someone or an animal. It might be referred to as a safe working area, safe working zone or safe working distance, but in practice a buffer zone might just be a designated area between two other areas that must also then be made safe.

An extreme example could be a mine field which might act as a buffer zone, but clearly it would not be safe to enter it.