Ventilation systems can be divided in many ways, by size, flow rate, velocity, material, placing, aim, etc. One common way is to divide between General Ventilation (GV) and Local Ventilation (LV). However, these terms do not have general accepted meanings. In the Design Guide Book for Industrial Ventilation (DGB), chapter 10 Local Ventilation, we (members of COST G3 Working Group 4) have tried to define and describe Local Ventilation systems. We have also made a division of L V into different specific systems.