Appendix: Factors of Deterioration

The following factors can affect the deterioration of objects in collections. They are often used as a basis for assessing the risks to a collection:

Contaminants and Pollutants

• accelerate metal corrosion
• contaminants may be from:
  – sulphur-containing gases (e.g. food, polluted air)
  – cleaning chemicals (especially aerosols)
  – soot, dust, and dirt
  – degrading plastics
  

Fire

• loss of collection

Handling (and other physical forces)

• corrodes metals (from salts and acids on bare hands)
• damages objects (e.g. scratching, dents, breakage)

Incorrect relative humidity

• corrodes metals above about 65% relative humidity

Incorrect temperature

• damages sensitive material (e.g. wood) associated with metals

Light

• fades light-sensitive material (e.g. ribbons) associated with metals

Pests

• attack organic material associated with metals

Security

• loss of portable, valuable, or rare objects

Water

• corrodes metals
• water may come from:
  – burst pipes
  – melting ice
  – leaks because of heavy rain and wind
  – floods
  – condensation