Rentokil - C.A.T Fumigation

Controlled Atmosphere Technology (C.A.T) is a specialised form of fumigation, relying on the use of either Carbon Dioxide or Nitrogen. It is used when items to be fumigated might be damaged by a more conventional fumigant such as Phosphine. Such items will include precious metals, copper, brass and it's alloys and silks.

An extremely high concentration of around 60% of Carbon Dioxide needs to be maintained for up to several weeks for this technique to be effective. A purpose designed container (or bubble) made from Oxygen barrier film is used.

Carbon Dioxide kills through a toxic effect on the insect pests and so to allow insects to continue to respire and be affected by the CO2 approximately 8% of Oxygen must remain in the bubble. Any more Oxygen and the treatment may fail.

Nitrogen can be used to eliminate insect pests as well and is typically used to treat paintings and musical instruments. This is the treatment of choice, as it's usage avoids the possibility of pigments suffering colour change or delicate items being subjected to sudden changes in humidity. Nitrogen has no toxic affect and is simply used to remove all the Oxygen from the controlled atmosphere. So that the insects die of Anoxia (or lack of Oxygen).

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