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Method Comparisons


Formaldehyde is a true gas and has many properties which make it a highly effective sterilizing agent. Being a true gas, formaldehyde has excellent distribution properties and will completely fill any area it is injected into. However, to be effective, formaldehyde requires long contact times (on the order of 6-12 hours) and the gas requires a post-exposure neutralization step after the contact time is completed. This neutralization step leaves residuals which must be cleaned after the decontamination. Formaldehyde is also a known carcinogen.

Principles of Effective Decontamination

The Principles of Effective Decontamination are the underlying fundamentals which must be achieved in order to ensure a successful decontamination cycle and apply to all decontaminating agents. Each agent's chemical and physical properties will affect the extent to which these principles are met and will influence the overall effectiveness of the decontamination cycle. Environmental factors will influence these properties and will play an important role in the effectiveness of your agent.

Complete Distribution

In order for any sterilant to be successful, it must reach all surfaces. True gases such as chlorine dioxide gas, formaldehyde, and ethylene oxide offer the best distribution properties. Liquids and vapors, such as hydrogen peroxide, are limited by temperature and environmental factors which negatively affect their distribution properties and effectiveness.

Total Penetration

In addition to complete distribution, the sterilant must be able to penetrate into all areas. As explained above, gases have superior penetration abilities as compared to liquid and vapor agents.

Concentration and Contact Time

Once your sterilizing agent has distributed to and thoroughly penetrated into all areas, it must remain there long enough to provide the desired level of kill. If it is difficult to get distribution and penetration throughout your target areas as it is for liquids and vapors, then it will also be a challenge to achieve the appropriate concentration and contact time required.

Factors Affecting Decontamination

Hard to Reach Areas
Cycle Development and Validation