Which way do you turn a valve?

A valve is a control component in a fluid conveying system, with functions such as cut off, regulation, diversion,prevention of back flow, voltage stabilization, diversion or overflow pressure relief. 

Generally, the valve is basically closed clockwise and opened counterclockwise; or in short“ Left-On,Right-Off”. 

Because most people are accustomed to using the right hand, it is easier to turn clockwise than counterclockwise when operating with the right hand. So it is relatively more reasonable to turn the switch counterclockwise to open and clockwise to close from the perspective of energy saving and safety. 

For valves with a hand-wheel, there will be a direction arrow or O→S logo on it( o is ON,S is OFF).