Certified Fire Protection Specialist (CFPS) — Question 14

When calculating friction loss in a sprinkler system, it is generally accepted that a 90° standard elbow of 2 in. (50 mm) in diameter is the equivalent of:

Answer options

• A. 2 feet of pipe (0.6 m)
• B. 3 feet of pipe (0.9 m)
• C. 5 feet of pipe (1.5m)
• D. 6 feet of pipe (1.8 m)

Correct answer: D

Explanation

The correct answer is D, as it is widely recognized that a 90° standard elbow of 2 in. diameter adds the equivalent friction loss of 6 feet of straight pipe. Options A, B, and C underestimate the friction loss introduced by the elbow, failing to account for the significant impact of bends in the piping system.