The latest CSA development is now available: the triple function anti water hammer air valve for buildings. Anti water hammer devices are crucial to prevent damage, vibration and problems caused by trapped air pockets. CSA combination air valves ensure air is vented for optimum working conditions, large volumes of air are admitted under vacuum conditions, and air is released in a controlled way to avoid sudden closing and the resulting water hammer with its devastating effects. A typical building installation of the FOX HR air valve would be at the change of gradient in a building, next to XLC 410 pressure reducing valves and downstream of a VSM sustaining valve for pressure control on each floor.