The Full Form of CWP is‍ Cold Working Pressure.

WOG stands for Water, Oil and Gas and is the non-shock pressure rating for valves at an ambient temperature. Water is straightforward but the oil and gas parts are a little more complicated. Oil refers to a free-flowing liquid that is thicker than water and has lubricating characteristics. Gas is a vaporized liquid, but this does not cover combustible gases. There are more specific approvals required for these applications.

CWP stands for Cold Working Pressure and is an indication of the pressure rating for valves at a temperature up to 100°F. This is becoming a more common rating, as the WOG rating has a more complicated description.

Both WOG and CWP refer to the pressure rating of the valve. They are found on the valve body as a number with either WOG or CWP under it. The number represents the pressure rating, ie a 600 with CWP under it would mean the valve is rated to 600 PSI CWP.