For a shell-and-tube heat exchanger, which tube pitch pattern would feature "see- through" lanes and would most easily allow external mechanical cleaning of the tubes?

Correct Answer: Option B — Square tube pitch

Square pitch arranges tubes in a grid pattern, creating clear, straight lanes between rows. These lanes allow for external mechanical cleaning using brushes or rods, which is critical for shell-side maintenance in systems prone to fouling, such as heavy fuel oil heaters or coolers handling viscous fluids.