Which construction type may contain a high concentration of wood that can contribute to a fire's intensity once ignition occurs?

Which construction type may contain a high concentration of wood that can contribute to a fire's intensity once ignition occurs?

• A. Type I
• B. Type IV
• C. Type V
• D. Type X

Answer: (B)

The main idea is that fire behavior is strongly influenced by how much combustible material is built into the structure. Heavy timber construction uses large wooden members throughout the building, so there is a substantial amount of wood acting as fuel within the structure itself. If ignition occurs, that significant wood content can feed the fire, leading to rapid growth and higher heat release, which increases the fire’s intensity. Other construction types rely less on wood for their structural framework (noncombustible or fire‑resistive systems) or use wood in a less concentrated way, and a fire in those buildings typically has less internal wood fuel to drive intensity. Type X, being a fire‑resistance rated material like gypsum board, does not provide the same wood fuel source as heavy timber.