The oxygen cylinder valve should be ______ open when in use?

The oxygen cylinder valve should be fully open when in use to ensure an adequate and consistent flow of oxygen to the equipment or system being operated. A fully open valve allows maximum pressure and volume of oxygen to be delivered, which is critical for maintaining the proper functioning of devices that rely on this gas, such as welding torches or medical equipment.

Opening the valve partially or only quarter open could restrict the flow of oxygen, leading to inefficient operation or potential hazards. A completely closed valve would stop the flow entirely, rendering the equipment inoperable. Therefore, setting the valve to a fully open position is essential for safety and efficiency.