Fire Department Incident Safety Officer Practice Test

Which type of building construction typically includes the use of heavy timber?

1. Type I

2. Type II

3. Type III

4. Type IV

The correct answer is: Type IV

Type IV construction, commonly referred to as "heavy timber" construction, is characterized by the use of large wooden structural members that are designed to limit fire spread and provide enhanced structural integrity. This type of construction features heavy wood columns, beams, and decking, which are typically unprotected and can resist fire for a significant period due to their mass. The design of heavy timber construction takes advantage of the fact that large mass timber can char on the outside while maintaining structural integrity on the inside, a phenomenon known as "charring." This results in a slower rate of heat transfer, allowing heavy timber structures to perform better during fire conditions compared to lighter, more combustible materials. It's also noteworthy that Type IV buildings often combine these heavy timber elements with masonry or other non-combustible materials, contributing to their overall resilience. Understanding the characteristics of Type IV construction is crucial for incident safety officers, as it informs strategies for fire attack and structural assessment during emergencies.