A reverse flow check may be needed with a PRV because which of the following?

A reverse flow check may be needed with a PRV because which of the following?

• A. A pressure spike could close the PRV
• B. An extra valve can't hurt anything
• C. It is needed for safety
• D. All of the above

Answer: (A)

The main idea is how a pressure reducing valve behaves during transient events. A PRV is designed to hold downstream pressure by throttling flow, but a sudden pressure spike can force the valve to shut quickly to protect the downstream side. When that happens, energy in the downstream line can push fluid back toward the upstream side if there’s any path for reverse flow. A reverse flow check valve provides a one-way path, stopping that backflow whenever the PRV closes or flow reverses due to a transient. That’s why it’s useful to have a reverse flow check with a PRV. The other options aren’t the primary engineering reason. While safety is always important, the specific need here is to prevent reverse flow during PRV closure caused by pressure spikes.

The main idea is how a pressure reducing valve behaves during transient events. A PRV is designed to hold downstream pressure by throttling flow, but a sudden pressure spike can force the valve to shut quickly to protect the downstream side. When that happens, energy in the downstream line can push fluid back toward the upstream side if there’s any path for reverse flow. A reverse flow check valve provides a one-way path, stopping that backflow whenever the PRV closes or flow reverses due to a transient. That’s why it’s useful to have a reverse flow check with a PRV.

The other options aren’t the primary engineering reason. While safety is always important, the specific need here is to prevent reverse flow during PRV closure caused by pressure spikes.