Which feature describes a Class 3 standpipe?

Which feature describes a Class 3 standpipe?

• A. This has both 1 1/2 inch and 2 1/2 inch connections
• B. Is continuously pressurized with water from a public supply
• C. Filled with pressurized air and upon opening of a hose a valve drops the air pressure that permits the dry pipe to activate
• D. Fire Department Connection

Answer: (A)

Class III standpipes are designed to serve both occupants and firefighters by providing two different outlet sizes: a 2 1/2-inch hose connection for firefighters and a 1 1/2-inch connection for occupants. That dual-outlet arrangement is the defining feature, which is why describing a standpipe as having both 1/2 inch and 2 1/2 inch connections fits Class III. The other statements describe aspects like continuous pressurization (wet vs. dry status), a dry pipe mechanism, or a Fire Department Connection that aren’t unique defining features of Class III.

Class III standpipes are designed to serve both occupants and firefighters by providing two different outlet sizes: a 2 1/2-inch hose connection for firefighters and a 1 1/2-inch connection for occupants. That dual-outlet arrangement is the defining feature, which is why describing a standpipe as having both 1/2 inch and 2 1/2 inch connections fits Class III. The other statements describe aspects like continuous pressurization (wet vs. dry status), a dry pipe mechanism, or a Fire Department Connection that aren’t unique defining features of Class III.