Which defensive strip variant is used to avoid purlin-based construction?

• A. A hose line
• B. Defensive Strip With Construction (Off Beam)
• C. Defensive Strip Against Construction (Off Purlin)
• D. Defensive Strip (LWP Roof Diagram)

Answer: (C)

Defensive strips are placed on a roof to control fire spread and create a safe venting path, and the way you set up the strip depends on the roof’s framing. When you want to avoid relying on purlin-supported construction, you choose the variant that is described as defensive strip against construction off purlin. This approach is specifically designed so the strip is formed in a way that does not depend on purlins for its support or alignment, reducing the risk if purlins are damaged or compromised. It typically means positioning and building the strip using areas and methods that bypass the purlin line, often using deck and other structural elements that aren’t purlins.

The other options don’t target avoiding purlin-based construction. A defensive strip built off beams still centers on beam-supported construction, not avoiding purlins. A variant labeled for an LWP roof diagram relates to lightweight roof configurations, not specifically to purlin avoidance. And a hose line is a firefighting tool rather than a defensive strip variant.