Buckstays are steel beams attached to the furnace wall with clips to contain a boiler's horizontal expansion.

• A. Buckstays
• B. Hangers
• C. Tie rods
• D. Lintels

Answer: (A)

This item tests understanding of structural restraints that limit how a boiler furnace moves when it heats up. Buckstays are steel beams fixed to the furnace wall with clips to restrain horizontal expansion, acting as bracing to keep the furnace and tube sheets from spreading apart under thermal load. This direct description matches their function, so they’re the best choice. Hangers are used to support components from above, tying rods provide tensile connections between frames, and lintels span openings in walls. None of these specifically restrain horizontal furnace expansion, so they don’t fit this purpose.