Cultural heritage, due to the variety of supports and materials from which it is made, is subject to a series of varied agents of degradation with very different consequences. Furthermore, it is rare for a collection to be subjected to only one category of degradation agents. In fact, cases in which these agents act in a combined manner are much more common, exponentially increasing the level of risk to which the collection is subjected.

For this reason, it is extremely complicated to be able to define in detail the different degradation agents that can act on a specific series of assets.

ICCROM, the International Center for Studies on the Conservation and Restoration of Cultural Heritage, has identified, in the 2016 manual A Guide to Risk Management of Cultural Heritage, the ten agents of degradation that most commonly affect cultural heritage.

We have listed them below.

Physical forces

This agent can be caused by natural events, such as erosion, winds, or earthquakes, or by human activities, such as improper handling, incorrect storage, construction work, traffic, incorrect transportation, and more.

The consequences of this type of degradation agent can also be very serious, causing tears, breakages, cracks, and abrasions, up to total destruction.

Criminals (thieves and vandals)

This agent of degradation is caused by criminal activity directly oriented towards damaging an asset, or a series of assets. These actions may have political, economic, or ideological motivations.

The consequences can be various; from defacement, sometimes minimal, to complete destruction, up to the total disappearance of an asset in the event of theft.

Fire

Fire can have many causes, especially if we think about historic buildings which are often not efficient from the point of view of fire prevention systems. Fire can arise from external causes or internal causes. Among the external causes, we find forest fires, construction or restoration works on buildings, or even armed conflicts. Among the internal causes, however, are lighting, malfunctioning electrical systems, smoking, the existence of kitchens or heat sources, and much more.

The consequences of fire on cultural heritage are disastrous. On a technical level, we talk about total or partial destruction, deformation caused by heat, soot deposits, and more.

Water

Water is perhaps the agent that most commonly affects cultural heritage. Here too, the causes can be multiple: they can derive from natural disasters, such as tsunamis, floods, river overflows, and heavy rains, or from internal malfunctions, such as leaks from plumbing systems or cleaning procedures. An extremely common cause, however, is that which derives from fire extinguishing procedures by the Fire Brigade.

Even for this agent, the consequences can be multiple. The most common are discolouration, corrosion, dissolution, deformation, and biological growth.

Pests (insects, rodents, etc.)

Assets preserved in museums, archives and libraries are often made up of organic materials, which represent an inviting food source for many species of pests, such as insects, rodents and birds. The cause of these infestations is often a lack of cleaning and maintenance of assets and the structures that store them.

If they act undisturbed, these agents can even lead to the complete destruction of cultural heritage. Less disastrous consequences, however, include stains, perforations, weakening of supports, loss of parts, and so on.

Pollutants

For institutions located in large cities or close to large industries, it is now increasingly common for collections to be seriously damaged by pollutants that can enter the conservation environments. The most common sources of these agents are industries, traffic, construction works, the storage of dangerous materials, and often also visitors, who introduce different types of polluting particles.

The consequences of these agents are discolouration, weakening, erosion and corrosion of the materials.

Lighting and UV rays

Incorrect management of lighting sources in conservation environments can be detrimental to cultural heritage. The main causes of this damage derive from the lack of shielding from UV rays and the use of artificial lighting sources that are not suitable for conservation.

The consequences of lighting on cultural heritage are colour fading, yellowing, weakening and disintegration.

Incorrect temperature

The causes of this agent can be environmental and therefore derive from the climate of the area in which the institution is located, or they can be caused by incorrect use of air conditioning systems or by the use of unsuitable lighting sources for conservation.

The most common consequences are an acceleration of degradation and ageing processes, deformation, dehydration and embrittlement of the materials that make up the assets.

Incorrect relative humidity

This agent can also derive from the climate of the area in which the museum is located, or from malfunctions or lack of maintenance of the air conditioning systems.

The most common consequences of moisture are warping, cracking, weakening, corrosion and discolouration. High humidity levels also favour the growth of mould and fungi, which can irreversibly damage assets made of organic materials.

Dissociation

The loss of part of an asset’s information and message is a very complex risk that is often forgotten. This is caused by a lack of or incorrect documentation and cataloguing of assets, the obsolescence of electronic or digital devices and, very often, the retirement of the institution’s staff.

The consequences can be the loss of objects or information linked to an object. This last consequence can determine the inability to recognize an asset or its symbolic value.

All the agents described are extremely dangerous for cultural heritage and can cause its total destruction. For this reason, the best prevention activity is always to constantly monitor the heritage and the structures in which it is preserved, to be able to identify the agents before they cause irreversible consequences on the objects. Furthermore, every cultural heritage conservation institution should be prepared to manage an emergency by planning and drafting a Security and Emergency Plan.