Museums are vital repositories of culture, history, and art, preserving artifacts that tell humanity's story. However, the preservation of these items faces challenges, particularly from environmental factors like humidity, temperature fluctuations, and pollutants. One effective solution to mitigate these issues is the use of museum desiccant control packs.
Conservation research has shown that RH levels above 65% will promote microbial growth (primarily fungi), while
RH levels below 25% can lead to brittleness and cracking. In addition, large fluctuations in RH can lead to
dimensional changes, deformation, and mechanical stress in organic materials. Though there is still debate about the
appropriate RH requirements for museum environments, a set point of 50% (or the historic building average) with
allowable fluctuations of ±5-10% is a generally accepted guideline.
Though mechanical humidification systems for RH control are common, many museums do not use them due to
factors such as cost and the difficulty integrating them with the existing building structure and aesthetics. An
alternate method of RH control that is employed in many museums is the use of an adsorbent material in
combination with a well-sealed display case to create a micro-environment that serves to mitigate the large RH
fluctuations that the general building environment may experience.
Understanding Humidity and Its Effects
Humidity refers to the amount of moisture in the air, and it plays a crucial role in the preservation of artifacts. High humidity levels can lead to mold growth, corrosion, and degradation of materials such as paper, textiles, and wood. Conversely, low humidity can cause drying, cracking, and brittleness, particularly in organic materials. Therefore, maintaining a stable and controlled environment is essential for the longevity of museum collections.
Benefits of Using Desiccant Control Packs
1. Moisture Regulation
The primary function of desiccant control packs is to regulate moisture levels. By absorbing excess humidity, these packs help prevent conditions conducive to mold growth and other forms of deterioration. Maintaining relative humidity between 30% and 50% is often ideal for most collections, and desiccants can help achieve this balance.
2. Protection Against Temperature Fluctuations
Temperature changes can also affect humidity levels. Desiccant packs can buffer these changes by absorbing moisture during warmer, humid conditions and releasing it during cooler, drier periods. This stabilization is crucial in environments where temperature control may be inconsistent.
3. Cost-Effective Solution
Compared to sophisticated climate control systems, desiccant control packs offer a cost-effective solution for humidity management. They require minimal maintenance and can be replaced easily, making them an accessible option for smaller museums or collectors who may not have extensive resources.
4. Versatility and Accessibility
Desiccant control packs come in various sizes and forms, making them versatile for different applications. Whether for large display cases or individual artifacts, they can be tailored to meet specific needs. Additionally, they are widely available, making it easy for museums to procure and implement them.
Best Practices for Use
To maximize the effectiveness of desiccant control packs, museums should follow best practices:
Monitor Humidity Levels: Use hygrometers to regularly check humidity levels and ensure that desiccant packs are effectively maintaining the desired range.
Replace Regularly: Desiccants have a limited capacity for moisture absorption. Regularly replacing or recharging them is crucial for ongoing effectiveness.
Combine with Other Methods: While desiccant packs are effective, they should be part of a broader preservation strategy that includes temperature control, air filtration, and proper storage techniques.