Question

OS&Y (Outside Stem and Yoke) gate valves are installed at several places in the standpipe system. These valves can be used to shut down part of the system as needed. Sections may also be shut down for testing, repairs or maintenance. The stem of an OS&Y valve must be kept in what position under normal conditions?

Answer 1

The stem of an OS&Y gate valve should be in the open position under normal conditions to ensure that the fire protection system is active, allowing for water flow.

Step-by-step explanation:

The stem of an OS&Y (Outside Stem and Yoke) gate valve should be in the open position under normal conditions. This type of valve is commonly installed in fire protection systems like standpipes, and the position of the stem indicates whether the valve is open or closed. When the OS&Y valve is open, the stem extends out from the valve body and the yoke is visible, which allows for a quick visual confirmation that the system is active and water can pass through. In contrast, when an OS&Y valve is closed, the stem is not visible as it is threaded down into the valve, blocking the water flow.