Introduction to Smoke and Soot Damage Restoration

Understanding how a fire burns and moves through a structure determines where smoke and soot are deposited, and therefore where remediation effort must be focused.

Fire triangle: fuel, heat, and oxygen — all three must be present for combustion. Understanding what was burning (fuel type) tells you what chemical byproducts are present in the smoke residue.

Stages of fire: incipient (initial smouldering), growth (accelerating combustion), fully developed (peak heat and smoke production), and decay (oxygen depletion or fuel exhaustion)

Smoke movement: hot gases and smoke rise, then move laterally under ceilings and through penetrations. Cold smoke from smouldering fires moves differently — settling in lower areas and penetrating more deeply into porous materials.

Pyrolysis: the chemical decomposition of organic material by heat — produces toxic residues including polycyclic aromatic hydrocarbons (PAHs), formaldehyde, hydrogen cyanide, and acrolein. These compounds persist in soot residue on surfaces.

Protein fires (cooking, biological material): produce a nearly invisible, oily residue with extremely strong odour — one of the most difficult smoke damage types to remediate. Soot deposits are not obvious visually but contamination is widespread.

Synthetic material fires (plastics, foam, cables): produce dark, oily, sticky soot with high PAH content — chemically aggressive to many building materials and surfaces

Field Action: On arrival at a fire-damaged property, identify the primary fuel type from the fire report or site evidence before beginning any assessment. This determines the chemical nature of the residue, the cleaning approach required, and the PPE specification for the job.

Compliance: Fire-damaged structures may contain compromised asbestos-containing materials, live electrical services, structural instability, and toxic pyrolysis residues. A full site hazard assessment is mandatory before any worker enters the structure.