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Description of key information

The flammability limits of pure TFE in air at 1atm pressure and 20°C have been established to be 13.0 to 43.4% (v/v).

Key value for chemical safety assessment

Flammability:
extremely flammable

Additional information

The flammability limits of TFE in air at 1atm pressure and 20°C have been established to be 13.0 to 43.4% (v/v). The flammability limits of TFE saturated with alpha-pinene (stabiliser) vapour at 15°C were found to be 10.9 to 42.4% (v/v).

Fuimara1989 states that at ambient room temperature and pressure, air and TFE will form a flammable mixture when the TFE molar percentage is between 6.5 and 46% or the volume percentage is between 14 and 43%, the latter being in agreement with the experimental values discussed above.

At 17.6 kg/cm2 gauge (250psig or 17atmg), the lower flammable limit for TFE was established to be 3.0 to 3.25% (v/v). This is much lower than the corresponding limit determined at 1atm. The upper limit is also affected by pressure, increasing markedly with relatively small increases in pressure.

Justification for classification or non-classification

The flammability limits of pure TFE in air at 1atm pressure and 20°C have been established to be 13.0 to 43.4% (v/v). Therefore as TFE is a gaseous substance that is flammable in contact with air at ambient temperatures and pressure it is classified as Extremely Flammable according to EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation EC No. 1272/2008. For transport, Tetrafluoroethylene (Stabilized) (UN 1081) is classified as a flammable gas belonging to division 2.1.