Fundamentals of preservation with climate control

Whether it is fine art, an historical document, electronic equipment or engineering material, the exact control of humidity, temperature and air purity is required to ensure that preservation is effective. Heat and humidity, as in Durban (South Africa), or winter fog in low-lying areas, are two extremes of temperature, both with relative humidity levels higher than 85%. Both conditions have the high corrosive potential to destroy valuable assets as well as create serious maintenance challenges.

Different materials require different conditions in order to maintain operational readiness or to protect them against moisture damage and decay. Reducing the moisture content in the air and keeping the relative humidity low reduces the oxidization (rust) potential in metals; prevents the absorption of moisture by hygroscopic materials; ensures consistent resistance values and reliability in electronics; and reduces the risk of mold or organic growth, all of which have an impact on maintenance costs and can in fact extend replacement cycles, if moisture content is correctly controlled.

Typically, if moisture is controlled to within a range of 50% to 55%, most materials will be protected against decay, ensuring effective preservation. In metals, once humidity levels pass 60%, corrosive attack occurs exponentially. Even with catalysts to corrosion in the air, such as salts, corrosion can be kept to a minimum if relative humidity is kept below that 60% level. The same can be said for moisture-related faults in electronics due to resistance values changing in hygroscopic components.

Maintaining the correct levels of humidity requires a high level of technical expertise. The balance is delicate: a low level of humidity removes ozone from the air, preventing organic and some synthetic materials such as leathers and rubbers becoming dry and brittle as a result of ozone-attack. The leather seats, rubber seals, tires and belts in precious vintage vehicles are a good example of this. However, too little humidity can cause expensive damage in organic materials, such as leather, fabrics, and canvas paintings – which should be kept above 50%, as a very dry environment will render them brittle and susceptible to cracking.

There are also significant health implications to the effective control of humidity. Mold in our homes, offices and public spaces such as conference centers and auditoriums as a result of cold temperatures without moisture control can result in bad odor and air-borne spores. This can pose a serious health hazard. Thus the effective prevention of the growth of mold assists us in averting high maintenance costs as well as personnel health issues.

Whatever your climate control need – whether it is precious artwork, archival maintenance or the protection of electronic or mechanical equipment, we can assist you with achieving the exact control of humidity, temperature and air purity for effective preservation. For more information and expert assistance please contact us.

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