How to understand ball valve markings


You may have noticed markings on brass and stainless st […]

You may have noticed markings on brass and stainless steel ball valves. These markings are not random, they help show the standards to which the ball valve has been tested and for which applications they can be used.

WOG stands for Water, Oil and Gas and is the non-shock pressure rating of the valve at ambient temperature. Water is simple, but the oil and gas part is a bit more complicated. Oil refers to a free-flowing liquid that is thicker than water and has lubricating properties. Gas is a vaporized liquid, but this does not include flammable gases. These applications require more specific approvals.

CWP stands for Cold Working Pressure and indicates the pressure rating of the valve at temperatures up to 100°F. This is becoming a more common rating as WOG ratings have more complex descriptions.

Both WOG and CWP refer to the pressure rating of the valve. They appear numerically on the valve body with WOG or CWP underneath. Numbers represent pressure ratings, i.e. 600 with CWP means the valve is rated at 600 PSI CWP.

WSP stands for Check Valve Working Steam Pressure, which defines the steam pressure in a system where a ball valve can be used. The industry uses WSP for bronze ball valves because the strength of the material decreases with increasing temperature.