The TNT equivalency method also uses an overpressure curve that applies to point source
detonations of TNT. Vapor cloud explosions (VCEs) are explosions that occur because of the
release of flammable vapor over a large volume and are most commonly deflagrations. In addition,
the method is unable to consider the effects of flame speed acceleration resulting from
confinement. As a result, the overpressure curve for TNT tends to overpredict the overpressure
near the VCE and to underpredict at distances away from the VCE.