Ball and butterfly valves are quarter-turn type valves that are widely used in the oil and gas industry for stopping and starting (isolation and opening) of the flow of fluid. Ball valves have a very robust design and they are a very common choice for aggressive process services involving flammable and possibly toxic fluids such as hydrocarbons. On the other hand, butterfly valves are lighter, more compact, and cheaper than ball valves, so they are a good choice for non-aggressive services such as water, oxygen, etc. Butterfly valves are not as robust as ball valves in process services, and therefore require higher maintenance costs. This paper aims to focus on the characteristics that make butterfly valves more suitable than ball valves in utility services. The parameters discussed are face-to-face, weight, and torque. Torque is a measure of how much force can act on a valve operator to rotate the valve closure member to be opened or closed. A comparison of the face-to-face (length) of ball and butterfly valves in Class 150 (pressure nominal 20) and size ranges of 4” to 20” shows that butterfly valves are approximately 84% more compact than even short pattern ball valves. It should be noted that utility services are mainly found in low pressure classes such as Class 150. Also, butterfly valves are not recommended to be used in sizes less than 4” due to pressure drop. The weight comparison between ball and butterfly valves in the above-mentioned size and pressure class shows that butterfly valves are approximately 75% lighter than ball valves. The last part of this paper compares the torque values and actuator size of 10” Class 150 butterfly and ball valves. The torque values of the butterfly valve are lower than the torque values of the ball valve, which leads to a more compact actuator, a mechanical device installed on the top of the valve for automatic operation. In fact, there is much space limitation on offshore platforms compared to onshore units. Additionally, offshore platforms have limited weight capacity so it is an advantage to save space and weight on the platforms through selecting a lighter and more compact valve.

butterfly valves, ball valves, oil and gas industry, offshore