Discharge nozzles shall be provided with an upstream device located immediately upstream of the nozzle. Which device is specified?

• A. External Strainer
• B. Internal Strainer
• C. Valve
• D. Filter

Answer: (B)

The need is to protect the discharge path from debris right at the point where the extinguishing agent leaves the nozzle. In cooking-fire suppression systems, solids and grease can be drawn into the discharge line, so having a screening device immediately upstream of the nozzle helps prevent clogging of the nozzle orifices and ensures reliable operation when the system is activated.

An internal strainer is built into the nozzle assembly and sits just before the discharge opening. This placement guards the nozzle while staying attached to the nozzle itself, which reduces the risk of missing or bypassed filtration and simplifies maintenance. External strainers or filters would add extra components and potential failure points, and a valve isn’t intended to serve as debris protection in the discharge path.