Towards Comprehensive Fire Risk Indexes for Cultural Heritage

Fire remains one of the most devastating threats to cultural heritage worldwide, with the potential to destroy not only historic buildings but also the invaluable and irreplaceable objects, decorations, and materials they contain. The unique and irreplaceable nature of many artefacts and artworks means that their loss or damage can represent a far greater cultural and historical loss than structural damage alone. Therefore, fire risk assessments must adopt a holistic approach that addresses all these aspects

In recent years, the use of Fire Risk Index (FRI) methodologies has gained significant traction as a tool for evaluating the vulnerability of heritage structures to fire events. While these indices represent an important step forward in risk analysis and prevention strategies, they are currently characterized by a significant limitation: they focus almost exclusively on the structural integrity of buildings, neglecting the protection of the movable heritage, interior decorations, and surface finishes that define the true identity and value of cultural assets.

In this regard, in the fire risk assessment professionals should always consider that:

• Non-structural artefacts and artworks: These are often irreplaceable and central to the cultural value of the site.
• Damage from fire byproducts: Smoke, heat, and corrosive gases can cause significant harm to artefacts, even if the fire is contained.
• Impact of extinguishing agents: Water, foam, powders, and chemicals used in suppression can themselves damage sensitive materials and artworks

The Incomplete Picture of Current Fire Risk Indices

Traditional Fire Risk Indices are primarily designed to assess the likelihood of fire ignition, the potential speed of fire spread, the structural resilience of the building, and the effectiveness of emergency response. These models, often adapted from standards used in industrial or commercial contexts, emphasize parameters such as:

• The presence and functionality of detection and suppression systems,
• Structural compartmentalization and material combustibility,
• Emergency access and egress routes.

While such considerations are undoubtedly critical, they paint an incomplete picture when applied to heritage contexts. The historical, artistic, and cultural value of a site is not limited to its architectural framework; it lies equally, if not more so, in the contents, finishes, and artistic expressions housed within.

A historic palace, church, library, or museum may survive structurally after a fire, but the loss of wall paintings, frescoes, wooden paneling, tapestries, books, or decorative surfaces can represent an irreparable cultural catastrophe.

What Current Models Overlook

1. Movable Heritage and Non-Structural Features
   Most Fire Risk Indices do not adequately account for the presence and vulnerability of movable collections (paintings, sculptures, manuscripts, furniture) or integral interior decorations (coffered ceilings, ornamental plaster, historic wallpapers). These elements are often made of highly combustible or fragile materials that can suffer irreversible damage from even minor fire events or smoke exposure.
2. Sensitivity to Fire Effluents and Extinguishing Agents
   Fire is not the only hazard: smoke, soot, heat, and suppression efforts (especially water or chemical extinguishants) can cause extensive and lasting harm to delicate surfaces, textiles, and pigments. Even without structural collapse or extensive combustion, cultural assets can be permanently damaged by the by-products of firefighting.
3. Lack of Material-Specific Vulnerability Data
   Most models use broad categories of materials without considering the differential thermal sensitivity, porosity, chemical stability, and surface fragility of heritage materials. For instance, the vulnerability of medieval parchment differs profoundly from that of Renaissance oil paintings or Baroque wooden sculptures, yet these distinctions are rarely reflected in risk assessments.

The Need for a Holistic, Heritage-Centered Fire Risk Approach

To advance the field of cultural heritage fire safety, there is an urgent need to develop more comprehensive Fire Risk Indices that:

• Integrate content vulnerability assessments, taking into account the specific materials, construction techniques, and artistic values of the objects and decorations present within heritage sites.
• Include the effects of combustion by-products and suppression techniques in their damage modeling.
• Allow for multi-criteria prioritization that balances structural preservation with the protection of the unique historical character and artistic integrity of each site.

Such models would require the collaboration of fire engineers, heritage conservators, materials scientists, and risk analysts to build interdisciplinary tools capable of reflecting the complex reality of cultural heritage assets.

Moving Towards International Standards

The development of international guidelines that embed these considerations is essential. While some progress has been made through organizations such as ICOMOS, ICCROM, and CEN, there is currently no widely adopted standard that fully addresses the holistic fire risk faced by cultural heritage.

Establishing such guidelines would not only improve the resilience of historic sites but also ensure that firefighting strategies and post-fire interventions are sensitive to the conservation needs of the collections and interiors.

Practical Steps

Although studies that take into account the vulnerability of objects of historical and artistic interest to combustion products and extinguishing agents are limited, some simple steps within the reach of the most experienced professionals in the field of cultural heritage safety can be suggested:

• Inventory and prioritize artefacts based on their vulnerability and value.
• Assess the impact of different fire suppression methods on various materials present in the building.
• Develop tailored emergency response plans that minimize collateral damage to collections during fire events

Key Takeaways for Cultural Heritage Professionals

In fire risk analysis for heritage and historic buildings, it is essential to consider not only the safety of human life and the structural integrity of the building, but also the potential damage to non-structural artefacts, artworks, and collections. This includes assessing risks from fire byproducts (such as smoke and corrosive gases) and the possible adverse effects of fire suppression agents on sensitive materials.

• Current Fire Risk Indices provide essential but incomplete assessments for heritage sites.
• There is a pressing need to develop risk models that consider not only structures but also contents, finishes, and decorative features.
• Effective protection demands an interdisciplinary approach, combining conservation science, fire engineering, and emergency planning.
• The international heritage community must strive to create shared frameworks and standards that reflect the unique challenges of fire safety in cultural heritage environments.