Low Burn Pattern (LBP)
Definition
Fire damage at or near floor level in a compartment. Historically misattributed solely to poured accelerants; now recognised as producible by post-flashover burning of ordinary furnishings without any introduced flammable liquid.
- Location
- Floor level of a compartment
- Old assumption
- Attributed solely to poured accelerant
- Current view
- Post-flashover burning alone can produce it
- Relevant to
- Fire cause and origin determination
Common questions
Why was this pattern once mistaken for proof of accelerant use?+
Investigators assumed that irregular, low burn damage near the floor could only occur where a poured liquid accelerant pooled and burned. Full-scale fire tests since the 1990s showed that flashover conditions alone, burning ordinary furnishings, reproduce the same patterns.
How did this change fire investigation practice?+
Investigators now require independent confirmation, such as canine alert plus laboratory analysis of debris, before attributing a low burn pattern to an ignitable liquid rather than concluding accelerant use from the visual pattern alone.
Related terms
- Backdraft
- A deflagration event triggered when air is suddenly admitted to a compartment where a fire has been oxygen-depleted but has continued to...
- Deflagration
- A subsonic combustion front propagating through an explosive by thermal conduction. Characteristic of low explosives such as black powder and smokeless powder;...
- Equivalence Ratio (Phi)
- The ratio of actual fuel supply rate to the stoichiometric fuel supply rate for the available air. Values below 1 indicate fuel-controlled...
- Flashover
- The near-simultaneous ignition of all exposed combustible surfaces in a compartment, occurring when the upper gas layer reaches approximately 600°C and radiative...
- Fuel-Controlled Fire
- A compartment fire in which the rate of energy release is limited by the fuel supply (surface area, arrangement, reactivity) rather than...
- Hot Gas Layer
- The stratified layer of buoyant combustion gases that accumulates at ceiling level in a compartment fire. Its temperature rise drives flashover when...
- Neutral Plane
- The interface between the hot gas layer above and the cooler ambient air layer below in a compartment fire. Above the neutral...
- Ventilation-Controlled Fire
- A compartment fire in which the rate of energy release is limited by air inflow through ventilation openings. Fuel-rich conditions produce high...
- Ventilation Factor
- A parameter used in fully developed fire characterisation, calculated as Av × Hv^0.5, where Av is the area of ventilation openings (m²)...