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Learn more about the anoxia method

The essence of the "anoxia atmosphere" method

The anoxic atmosphere method (oxygen-free medium) is a technique for eradicating and controlling pests. It is an oxygen removal process in a closed space in which materials or objects are isolated for treatment or preventive measures.

The results are dehydration and suffocation of microorganisms and insects (egg, cacoon, larva, adults), regardless of the evolutionary stage of development. Inert nitrogen gas is often used. It does not kill directly but prevents the unwanted influence by the lack of oxygen needed to continue the life of the pests.

The anoxia method is applicable to all types of organic (paper, leather, fabric, wood) and inorganic materials. Since anoxia is a non-toxic method for both humans and the environment, it is widely distributed as a suitable alternative within the concept of protecting collections and cultural heritage.

Creating an oxygen-deficient micro-environment is a real prospect of long-term storage (not just documents on a different medium), not only because it is safe, non-toxic and totally inert with regard to the treated material, but also because it slows down the process of degradation and destruction of sensitive and vulnerable documents mainly caused by oxygen, pollutants and inadequate humidity and temperature levels.

Anoxia could be applied on-site and organized in the form and size required for treatment or prevention the so-called baloon. The balloon is made of special nylon with a high degree of oxygen impermeability. Air in the bubble is replaced by inert gas (nitrogen, argon or CO2).

An automatic, Anoxia hk 3M system for curing and prevention, for long and systematic treatment of documents and archival materials as well as other cultural heritage sites.

This system allows to define the operating conditions and to control the environment parameters in the chamber, causing an adequate environment with a low oxygen level. The work, control and register mechanisms are automated and determined.

Anoxia disinfection and disinsection with oxygen absorbers   

This method of treatment is applicable to smaller objects that can be treated in small or medium bags made of high-bay polyamide (nylon), the so-called Anoxia capsule.

The anoxia capsule allows the long-term storage of valuable documents under an anixia conditions, eliminating the major factors and degradation processes, the oxidation, biological and microbiological degradation of the documents placed in the capsule.

 The system uses oxygen absorbers in an amount sufficient to provide a level below 0.3% of oxygen during treatment. a simple visual oxygen indicator is placed or this concentration is monitored with an electronic monitor.

  1. Selwitz, C., S. Maekawa. Inert Gases in the Control of Museum Insect Pests. Los Angeles : The Getty Conservation Institute, 1998.

  2. Schäfer, S. Desinfestação com métodos alternativos, atóxicos e Manejo Integrado de Pragas (MIP) em museus, arquivos e acervos & Armazenamento de objetos em atmosfera modifica. Associação Brasileira de Encadernação e Restauro, São Paulo, 2002. <>

  3. Schäfer conservação-restauro. Cápsula do tempo: Proteção total para sua obra de arte. 2010. <>

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