During a quarterly inspection, excessive sediment is found in the bottom of the foam tank. What is the proper corrective action per NFPA 25?

• A. Drain and flush the tank
• B. Replace the strainer
• C. Add clean water
• D. Increase foam concentration

Answer: (A)

Sediment in the foam tank signals contamination that can affect foam solution quality and the system’s ability to proportion concentrate properly. Draining the tank and flushing with clean water removes the sediment and any settled debris, restoring a clean reservoir for the concentrate and preventing it from entering the proportioning path. After draining, the tank should be refilled with the correct foam concentrate to the proper level and the system should be tested to confirm foam characteristics meet specifications. Adding clean water and increasing foam concentration won’t fix the issue—they either dilute the mix or introduce other performance problems, and replacing a downstream component like a strainer doesn’t remove the sediment from the tank itself. Regular cleaning per NFPA 25 helps maintain reliable foam performance.