Which of the following is a key characteristic of non-combustible construction?

The key characteristic of non-combustible construction is that it does not contribute to fire load. This means that the materials used in non-combustible construction are designed to withstand fire without burning, thereby minimizing the amount of fuel that can be available for combustion.

In practical terms, non-combustible construction typically involves the use of materials such as concrete, steel, and masonry. These materials can withstand high temperatures and do not ignite, which makes them ideal for creating safe environments. By not contributing to fire load, non-combustible structures help to contain fires and prevent their spread, which is a central concern in fire safety and building codes.

The other options do not align with the definition of non-combustible construction. Extensive fireproofing is generally required for combustible materials to enhance their fire resistance; non-combustible materials are inherently resistant. Non-combustible construction is not made entirely of wood, as wood is considered a combustible material, which would contradict the concept of non-combustibility. Finally, while insulation is important for energy efficiency, heavy insulation is not a defining feature of non-combustible construction and can actually be made from both combustible and non-combustible materials.