What type of steel beams are attached to the furnace wall with clips to contain a boiler's horizontal expansion?

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

Answer: (C)

When a boiler heats up, the furnace wall tends to expand horizontally. To keep the walls from buckling or deforming under that expansion, engineers install buckstays. These are horizontal steel beams that run across the furnace and are clipped to the furnace wall, creating a stiff frame that resists outward movement and maintains the shell’s shape and alignment as it grows with heat. Lintels are architectural elements above openings, hangers are for supporting components, and tie rods connect parts but don’t serve the specific role of constraining horizontal expansion across the furnace, so buckstays are the appropriate choice here.