Ignitable Liquid
Definition
In fire debris analysis, any flammable liquid that could serve as an accelerant. E1618 classifies ignitable liquids into eight categories based on GC-MS pattern rather than common commercial names.
- Standard classification system
- ASTM E1618, which divides ignitable liquids into eight classes
- Key forensic technique
- Gas chromatography-mass spectrometry (GC-MS) for pattern analysis
- Definition basis
- Intent: intentionally introduced to start or accelerate a fire
Common questions
What exactly is an ignitable liquid in forensics?+
An ignitable liquid is a flammable or combustible liquid that someone deliberately used to start or speed up a fire. In fire investigations, these are any flammable liquids that could have served as accelerants. They're classified using laboratory analysis rather than brand names.
How are ignitable liquids classified?+
Ignitable liquids are sorted into eight classes using ASTM E1618, which groups them by their boiling-range fraction and chemical family. Fire debris analysts use GC-MS (gas chromatography-mass spectrometry) pattern matching to identify which class a sample belongs to, rather than relying on what product it might be from.
Why does the forensic classification system matter?+
Using ASTM E1618 standardizes how fire accelerants are identified across investigations. The pattern-based approach is more reliable for linking residues in fire debris to the original liquid, since the same chemical family can come from many different commercial products.
Related terms
- Extracted Ion Profile (EIP)
- A GC-MS chromatographic display plotting only ions of a specified m/z value against retention time, effectively filtering out all compounds that do...
- ASTM E1387 / E1618
- ASTM standards for ignitable-liquid residue analysis. E1387 was the older colour-coded scheme; E1618 (current) defines the modern eight-class system based on GC-MS...
- ASTM E1618
- Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry. The active analytical standard defining...
- DB-5 Column
- A gas chromatography capillary column with a 5% phenyl-95% dimethylpolysiloxane stationary phase, the standard column for fire debris GC-MS analysis. Provides adequate...
- Isoparaffinic Products
- An E1618 category of ignitable liquid dominated by branched-chain (isoparaffinic) alkanes with minimal aromatic or n-alkane content. Examples include Isopar solvents and...
- OSAC (Fire and Explosion)
- Organisation of Scientific Area Committees, Fire and Explosion Investigation Subcommittee, under NIST. Develops and publishes standards and needs statements for fire investigation...
- Passive Headspace Charcoal-Strip Extraction
- ASTM E1412 method. Fire debris is sealed in an unlined metal can with a suspended activated-charcoal strip, heated to 60 to 80...
- Passive Headspace Concentration (PHC)
- ASTM E1412 extraction method. The sealed evidence container is heated at 60-80°C; volatilised hydrocarbons adsorb onto an activated charcoal strip suspended in...
- Petroleum Fractions
- Crude-oil distillation cuts ordered by boiling range: light (C4 to C9, pentane, hexane, naphtha), medium (C8 to C12, mineral spirits, kerosene), heavy...
- Pyrolysis Products
- Hydrocarbons released when synthetic substrates (polyurethane foam, carpet, vinyl flooring) burn or smoulder. They overlap the petroleum range and are the main...
- SPME
- Solid-phase microextraction. A polymer-coated fused-silica fibre (typically PDMS or PDMS-DVB) is exposed to vial headspace, then thermally desorbed in the GC injector....
- SWGFEX
- Scientific Working Group for Fire and Explosion Investigation. A US-based multidisciplinary body that developed best practice guides for fire debris collection, canine...
Explained in these topics
- Analysis of Petroleum Products and Fire AccelerantsAny flammable or combustible liquid intentionally introduced to start or accelerate a fire. ASTM E1618 places ignitable liquids into eight classes by boiling-r...
- Fire Debris Analysis: GC-MS and ASTM E1618 Pattern RecognitionIn fire debris analysis, any flammable liquid that could serve as an accelerant. E1618 classifies ignitable liquids into eight categories based on GC-MS patter...