Single orifice air valve is one type of single ball air release valve with threaded ends for small sizes, and flanged ends for big sizes. Air valve is one important exhaust valve in the long big piping transport, which is normally mounted on the top of the pipe or pipe air holding place to release the air in the pipe, making sure the pipe work normally. Single orifice air valve can remove the air existed in the pipe more flexible, preventing of the pressure fluctuation or other damages in the piping system. Single orifice air valve is applicable especially to the main water pipes, sewage pipes and deep well pumps piping system.