Many pipe bursts in water distribution systems are caused by entrapped air. Air valves are the devices responsible for releasing and admitting air into the pipe. However, the dynamic behaviour of these elements is not very well known and the number of references on this topic is limited and scarce. Comprehensive air admission and release tests for determining the dynamic behaviour of air valves were carried out at WL| Delft hydraulics laboratory for DN50 and DN100 air valves, mounted on a 200mm and 500mm pipe respectively. In this paper, a brief description of the experimental set up and test procedures is provided. Some conclusions about the importance of different parameters on the peak pressure magnitude, such as terminal water velocity, residual air volume, moving water column inertia, are also presented.