The heat source for the fire test should be provided by
a Butane or Propane fuelled Bunsen or Tirril burner with a nominal
9.525mm (3/8inch) inside diameter tube adjusted to give a pre-mixed
air/gas flame of 38.1mm (1½ inch) length. The minimum temperature
measured in the centre of the flame with a calibrated thermocouple
pyrometer must be 843.33°C (1550°F).