Which option represents a Defensive Strategy component for Lightweight framing?

• A. Defensive Strip (Conventional)
• B. Defensive Strip (LWP, done off Beam or Purlin)
• C. Heat Hole
• D. Offensive Hole

Answer: (B)

Defensive ventilation in lightweight framing focuses on removing fuel and reducing heat without compromising the structural members that carry the roof. Lightweight roof assemblies—like those with trusses and minimal redundancy—can fail quickly if you cut into the load paths or create openings that destabilize the structure. The Defensive Strip method for lightweight framing is done off the beam or purlin, meaning you strip roofing and combustible materials from the exterior side without cutting through or stressing the main load-bearing members. This approach lowers the fire load above the area of involvement while keeping the roof’s structural members intact, reducing the risk of a sudden collapse and helping to control the fire environment for crews inside.

The other options don’t fit this defensive approach for lightweight framing: a defensive strip for conventional construction targets different structural realities, while heat holes or offensive holes are venting strategies typically associated with offensive or different tactical aims and can be riskier with lightweight roofs.