What is the friction loss in 500 feet of 5-inch hose flowing 1250 gpm?

• A. 45 PSI
• B. 50 PSI
• C. 72 PSI
• D. 62.5 PSI

Answer: (D)

Friction loss in hose is the pressure drop caused by moving water through the hose, and in fire practice you use friction loss per 100 feet for the given hose size and flow, then scale by the actual length. For a 5-inch hose carrying 1250 gpm, the standard friction loss chart gives about 12.5 psi per 100 feet. Since the hose run is 500 feet, that’s five sections of 100 feet, so the total friction loss is 12.5 psi × 5 = 62.5 psi. That’s why the correct answer is 62.5 psi. The other options would require different per-100-foot values or a different total length, which don’t match the table for these conditions.