What is the purpose of a cut-off valve in a piping system?

• A. To regulate flow rate
• B. To completely stop the flow
• C. To enhance pressure
• D. To promote drainage

Answer: (B)

A cut-off valve is specifically designed to completely stop the flow of fluid within a piping system. This is particularly important for maintenance or repair work, allowing for specific sections of the system to be isolated without affecting the entire network of pipes. By using a cut-off valve, operators can ensure that fluid does not escape while they work on piping or equipment downstream of the valve.

In context, while other valves can regulate flow or facilitate drainage, they do not serve the primary function of stopping flow entirely. The capability to stop flow completely is essential in a variety of applications, such as when needing to ensure safety during maintenance or when a section of the system needs to be decommissioned for any reason. Thus, the function of a cut-off valve plays a crucial role in maintaining the integrity and safety of a piping system.