🏗️ 8D — Construction, Renovation & Special Hazards

What is a bowstring truss?

A truss roof system commonly recognized by its arched or curved outline and historically used for large commercial or industrial structures.

Where were bowstring trusses commonly used?

Automobile dealerships and repair facilities, bowling alleys, grocery stores, and industrial complexes.

Why are older bowstring trusses especially concerning?

Trusses built before the late 1960s may have code deficiencies, including inadequate tensile strength in bottom chord members.

Why are preincident surveys useful for bowstring truss buildings?

They can reveal hidden construction features that may not be obvious during an emergency.

What happens to fire risk when a building is under construction, renovation, or awaiting demolition?

The risk of fire rises sharply.

What factors increase fire risk during construction or renovation?

Additional fuel loads and ignition sources such as cutting torches, grinding, and welding.

Why do partially completed buildings spread fire rapidly?

Protective features such as gypsum wallboard and automatic suppression systems may not yet be installed.

Why are exposed wooden frames in unfinished buildings dangerous?

They can behave like a vertical lumberyard and provide large amounts of combustible fuel.

What conditions can make abandoned or renovated buildings especially dangerous?

Breached walls, open stairwells, missing doors, deactivated suppression systems, altered components, deterioration, and increased collapse potential.

Why can renovation work make firefighter entry more difficult?

Debris and construction materials can block exits and impede both occupants and firefighters.