Q. Why we use Air Valves?

Air Valves - Air valves of proper size and pressure rating at summits. Air valves ensure the safety of the pipe line against collapse when at points of low pressure. When it is placed below the gate valve, it protects the pipe against the negative which may develop because when the gate valve is suddenly closed, water continues to flow and vacuum gets created on the down stream side of gate valve. Air valve opens out automatically when the pressure falls below the limit.