🏗️ 8B — Modern/Legacy Construction & Fire Behavior

How can combustible exterior wall coverings affect fire spread?

They can add wood or petroleum-based fuels to the building and spread fire to other areas or adjacent exposures.

Why are combustible roofs a community fire hazard?

Flaming embers can ignite combustible roof coverings and spread fire from building to building.

Why are wood shakes dangerous during wildland/urban interface fires?

They can significantly contribute to fire spread even when treated with fire retardant.

What can happen when combustible materials are installed over a metal roof deck?

Fire below the deck can melt or ignite combustible insulation or roofing layers and cause fire above the roof.

How does building compartmentation affect fire behavior?

It affects fire development, severity, duration, and intensity.

What building layout features affect fire development?

Number of stories, floor plan, openings between floors, continuous voids/concealed spaces, and barriers to fire spread.

How can compartmentation help firefighters?

Fire-rated walls, ceilings, and doors can separate fuel sources and limit fire development to individual compartments.

When are two rooms considered separate compartments?

When the doorway between them is closed.

How can firefighters use doors during interior operations?

Doors can be closed when appropriate to control oxygen sources and flow paths.

What is a major difference between modern and older residential construction?

Older structures generally had smaller, more numerous compartments, while modern homes often have open floor plans and lightweight construction.

What features may be found in modern single-family homes?

Open floor plans, high ceilings, atriums, lightweight manufactured structural components, sealed windows, wall cavities, and synthetic insulation.

How have synthetic construction materials affected fire behavior?

They increase fuel loads and can produce large quantities of toxic and combustible gases.

Why can energy-efficient buildings create difficult fire conditions?

They can contain fires longer and create fuel-rich, ventilation-limited environments.

Why are open-plan commercial buildings challenging?

They can have high fuel loads and few physical barriers to prevent fire and smoke spread.

Why are plastics and synthetic materials important in fire behavior?

They can cause fires to escalate rapidly, reach high temperatures, and consume available oxygen quickly.