In a cold water system, what happens to head loss as pipe length increases and fittings increase?

• A. Head loss decreases
• B. Head loss remains the same
• C. Head loss increases
• D. Head loss fluctuates randomly

Answer: (C)

Head loss comes from resistance to flow, and in a cold water system that resistance adds up from two sources: friction along the pipe and losses at fittings. When the pipe length increases, you’ve got more surface for the fluid to rub against, so the friction loss grows in direct proportion to the length (for a given diameter and flow). The friction portion is often described by h_f ~ f (L/D) (V^2/(2g)), which shows that longer length means more head loss.

Each fitting adds its own small drop, described as a minor loss h_f,minor = K (V^2/(2g)). More fittings mean more of these drops, increasing the total head loss.

So the total head loss goes up as you add length or more fittings. It wouldn’t decrease, stay the same, or fluctuate randomly because resistance to flow only increases with more path or more obstacles in the way.