Caring for Cultural Material 1

Caring for Cultural Material 2

Damage and Decay

Managing Collections

Managing People

Handling, Transportation, Storage and Display

Glossary

Index

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Damage and Decay
In this volume:
– Light and Ultraviolet Radiation
arrow Humidity and Temperature
– Biological Pests
– Dust and Pollutants
– Common Deterioration Processes
– Acknowledgments
Humidity and Temperature
In this chapter:
– Objectives
– Introduction
– What is relative humidity?
– How does relative humidity change?
– Why worry about relative humidity and temperature?
– Can the damage be prevented?
arrow Identifying the source of the problem
– What can be done to minimise damage?
– Modifying the conditions in buildings
– A word of caution about travelling exhibitions and loans
– In an ideal world …
– Australia’s climatic zones
  MORE ABOUT RELATIVE HUMIDITY AND TEMPERATURE
– Measuring relative humidity
– Dehumidifiers
– Humidifiers and steam generators
– The use of silica gel
– For further reading
– Self-evaluation quiz
– Answers to self-evaluation quiz

 

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Humidity and Temperature

Identifying the source of the problem

Extremes and fluctuations in relative humidity and temperature which damage collections are experienced in many museums, galleries and libraries. These changes can be caused by:

  • the regional climate;

  • the climate within buildings;

  • localised climates with buildings;

  • microclimates; and

  • visitors.

Australia is a large country with three very different climates—tropical, arid and temperate. Regional climates are particularly significant for objects which are displayed outside.

Because buildings are not fully sealed, outside conditions have a significant influence on the climate inside the building. The building's style, the materials used, the state of repair of the building and whether the building is insulated, air-conditioned or without either, all influence the impact outside conditions have on the climate inside the building.

Although buildings are not fully sealed from the outside weather, they act as barriers to the free flow of heat and moisture. This is why air-conditioning and heating are effective in providing a comfortable climate.

Within buildings there are localised climates and microclimates where conditions vary greatly from conditions in other parts of the building. For example, there would be greater variations in temperature and humidity in a small tea room with a toaster and a kettle than there would be in a closed-off storage area.

Cupboards, display cases, boxes and frames act as barriers to air and moisture circulation and can develop their own microclimate. The materials used to make the display cases, boxes and frames, combined with what's stored in them, also influence the microclimate.

People are important to the museums, galleries and libraries. The effect they have on the local climate depends on:

  • how many visitors there are and whether they arrive individually or in groups;

  • whether they have wet or damp umbrellas and coats;

  • how long they stay; and

  • their ages—school groups are potentially more disruptive to a controlled environment than adult tour groups or individuals.

All of these factors can contribute to fluctuations in, and problems with, relative humidity. Careful manipulation of these factors helps create a stable environment where the risk of damage is minimised.

 

 

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