After operation with foam, foam water-deluge and spray systems shall be flushed with water to remove foam residue. Which option is correct?

• A. Flush with water
• B. Seal system
• C. Repeat foam operation
• D. Flush with alcohol

Answer: (A)

After foam operation on foam‑water deluge and spray systems, flushing with water is needed to remove any foam concentrate residue. Foam concentrates can leave sticky, residues inside piping, valves, nozzles, and strainers. If these residues are not washed out, they can clog components, alter flow, or interfere with future water service. Water flushing dilutes and carries the residue out through drains, returning the system to a clean, water‑only condition and reducing the risk of blockages or incompatibility with subsequent use. Sealing the system would trap residues and potential debris inside; repeating another foam operation would add more foam residue rather than clean it; flushing with alcohol isn’t appropriate for these systems because it can introduce incompatible chemicals and safety concerns.