Fumes may also contain organics, volatile metals, flourides and sulphur oxides, which should be removed. Virtually eliminates odors from lusters, metallics and sulphur. Kiln stays under negative pressure to provide complete fume removal. Hoods can't do this. Air brought into the kiln replaces carbon monoxide and adds oxygen needed for reds, greens, golds and yellows.
Colors are brighter and more vibrant and different colors can be fired together.
Hot gases are circulated, providing more uniform temperatures, important for glazes and porcelains with narrow firing ranges. Hot gas from the kiln mixes with room air to provide cool exhaust. Oxygen brought into kilns burns carbon and organics in bodies and glazes. This helps reduce crazing, pinholing and porcelain mildew. Oxygen in the kiln reduces corrosion of metal heating elements and Kiln-Sitter parts.