Fire Safety in Cultural Heritage Buildings: Beyond Compliance, Toward Protection

Fire is arguably the greatest single threat facing cultural heritage. From the catastrophic 2018 fire at the National Museum of Brazil — which destroyed an estimated 20 million artefacts — to the Notre-Dame blaze of 2019, the record speaks for itself. Yet despite the scale of the risk, fire safety in historic and museum buildings remains one of the most technically complex and often misunderstood disciplines in the built environment sector.

The challenge is not simply one of compliance: it is one of reconciling the imperatives of life safety, structural preservation, and — critically — the protection of irreplaceable collections.

The Regulatory Paradox: Where Norms Meet History

Current fire safety regulations in most European jurisdictions — including the Italian Codice di Prevenzione Incendi – Fire Prevention Code (D.M. 3 maggio 2004 and its successors) — are built around a set of prescriptive requirements developed largely for new construction.

Compartmentation, escape route widths, structural fire resistance ratings, sprinkler installation: these measures are well-tested and effective in buildings designed to accommodate them. Historic structures, however, were not.

When applied to a 16th-century palazzo, an 18th-century villa converted into a civic museum, or a medieval monastery repurposed as an archive, prescriptive compliance can quickly become structurally destructive, aesthetically ruinous, or simply physically impossible. The constraints are numerous and often compounding:

• Structural fabric. Load-bearing masonry walls, timber roof structures, vaulted ceilings, and historic floor systems cannot be modified without potentially compromising the architectural integrity that the Soprintendenza is mandated to protect. Installing conventional fire doors in original doorways, cutting service shafts for sprinkler pipework, or applying fire-resistant cladding to exposed timber beams may be flatly prohibited by the heritage authority.
• Escape route geometry. Medieval staircases are narrow, steep, and often irregular. Corridors may not meet minimum widths. In many cases, the only means of egress passes through rooms containing collections — a configuration entirely at odds with standard evacuation logic.
• Compartmentation. The open, interconnected spatial sequences that define the aesthetic and experiential quality of historic interiors — enfilades of rooms, grand salons, open galleries — are fundamentally hostile to the compartmentation strategies that prescriptive codes rely upon.
• Suppression systems. The installation of automatic sprinkler, water mist or other systems — effective as they are — raises serious concerns in environments housing works on canvas, paper, parchment, or polychrome surfaces. Water itself is a damaging agent, and the visual intrusion of distribution pipework and heads may be unacceptable in decorated interiors.

The result is a structural tension: the prescriptive route to compliance is often blocked by the very constraints that define the building’s heritage value. This is not a marginal problem affecting a handful of exceptional monuments — it is the daily reality for the overwhelming majority of Italy’s (and Europe’s) museum and heritage estate.

The Case for Performance-Based Fire Safety Engineering (FSE)

The solution, increasingly recognised in both regulatory frameworks and professional practice, is the performance-based or Fire Safety Engineering (FSE) approach. Rather than asking “does the building comply with rule X?”, FSE asks “what level of safety does the building actually achieve, and how can that level be demonstrated and, where necessary, improved?”

The Italian Codice di Prevenzione Incendi explicitly supports this approach via its Metodo Ingegneristico (Engineering Method) – Chapter G.2 and the associated M section.  This allows designers to replace prescriptive measures with engineered equivalents provided they can demonstrate defined performance levels in terms of life safety structural resistance and fire spread limitation through quantitative analysis.

In practical terms, FSE for a heritage building typically involves:

1. Fire scenario definition — identifying credible ignition sources, fuel loads, occupancy patterns, and spatial configurations that bound the range of plausible fire events. 
2. Computational fire modelling — using validated CFD tools (most commonly FDS — Fire Dynamics Simulator) to simulate fire growth, smoke movement, temperature fields, and toxic gas concentrations under each scenario. 
3. Evacuation modelling — assessing the Available Safe Egress Time (ASET) against the Required Safe Egress Time (RSET) for all occupant groups, including visitors unfamiliar with the building and staff with defined roles. 
4. Compensatory measure design — identifying alternative or enhanced measures (advanced detection, smoke control, trained staff protocols, operational restrictions) that, in combination, achieve the required performance level without the physical interventions that heritage constraints preclude. 

The FSE process is resource-intensive and demands multi-disciplinary collaboration — fire engineers, architects, heritage specialists, and the fire authority must engage iteratively. But it is, in many cases, the only viable pathway to a technically sound and heritage-compatible outcome.

The Third Dimension: Protecting Collections from Fire — Not Just from Flames

Here lies the issue that prescriptive frameworks address poorly, and that FSE teams must consciously and explicitly build into their analyses: the protection of moveable collections, frescoes, and decorative surfaces is not the same problem as the protection of human life or structural fabric.

Standard fire safety objectives — life safety, property protection, continuity of operations — are insufficient when the “property” in question is a Caravaggio, a cycle of 15th-century frescoes, or an archive of original manuscripts. Two distinct damage mechanisms demand attention:

1. Thermal Damage

Elevated temperatures cause irreversible damage to artworks well below the thresholds at which structural failure occurs or human life is threatened. Key thresholds that FSE analysts and collection managers must be aware of include:

• Panel paintings and polychrome surfaces begin to suffer delamination and cracking at temperatures above 50–60°C, as differential thermal expansion between substrate and paint layers induces mechanical stress. 
• Textile and paper artefacts (tapestries, drawings, manuscripts) are highly vulnerable from approximately 70°C, with rapid degradation at higher temperatures. 
• Fresco and plaster surfaces are susceptible to thermal shock and moisture-driven spalling even at relatively moderate temperatures, particularly when exposed to the rapid thermal gradients associated with fire suppression (whether water-based or gaseous). 
• Bronze and metal artefacts are generally more thermally robust, but their surface patinas and any associated organic elements (lacquers, bindings, textile mounts) are not. 

The spatial distribution of these temperature thresholds — how quickly, and how far from the fire origin, temperatures exceeding these values propagate — must be a defined output parameter of the CFD fire model, not an afterthought.

2. Soot Deposition

This is the damage mechanism most frequently overlooked in standard FSE analyses, yet it may be the one with the most widespread consequences in a museum or decorated interior. Soot — the fine carbonaceous particulate produced by incomplete combustion — is chemically aggressive, visually disfiguring, and extraordinarily difficult to remove from porous, textured, or painted surfaces without causing further damage.

In a typical building fire, significant soot deposition can occur in spaces that experience no direct flame impingement and no structurally significant temperature rise. Smoke — and with it, particulates — travels through entire compartments, stairwells, and adjacent rooms driven by buoyancy, ventilation flows, and HVAC systems long before a fire is detected and suppressed. In an interconnected historic interior with limited compartmentation, this means that rooms containing irreplaceable works may be contaminated by a fire whose origin is elsewhere in the building.

The conservation implications are severe. Soot deposited on an oil painting, a polychrome altarpiece, or a fresco surface:

• Chemically bonds to varnish and paint media within hours of deposition 
• Penetrates micro-porous surfaces, making removal without abrasion extremely difficult 
• Causes photochemical darkening under UV exposure even at very low concentrations 
• May carry corrosive acids (particularly from the combustion of synthetic materials) that actively degrade adjacent surfaces 

For this reason, FSE analyses developed for heritage and museum contexts must explicitly model smoke and particulate transport across the full range of fire scenarios, with specific attention to:

• The spatial extent of the smoke layer at defined time intervals 
• The concentration of particulates in smoke reaching collection areas 
• The effectiveness of smoke containment or extraction measures in limiting contamination spread 
• The role of HVAC systems — which, if not equipped with automatic isolation, can actively distribute smoke and particulates into clean areas 

Defining the Right Brief for FSE in Heritage Contexts

The practical implication for facility managers and heritage operators is this: when commissioning an FSE study for a museum, historic building, or cultural heritage site, the brief must explicitly define the protection of collections — including soot and thermal damage to artefacts — as a primary performance objective, not a secondary consideration. This means specifying:

• Damage thresholds for each category of collection item present, in terms of both temperature and smoke/particulate exposure 
• Critical zones — rooms or areas containing the highest-value or most vulnerable artefacts — as priority protection targets in scenario definition 
• Acceptance criteria for smoke spread that go beyond simple tenability thresholds for human occupants 
• Suppression system selection criteria that account for the risk of water or agent damage to collections (in many contexts, clean agent or inert gas systems in critical areas, complemented by sprinklers in non-collection spaces, represent the appropriate balance) 

The dialogue between the FSE team and the collection conservators is not optional: it is the technical foundation on which the entire analysis must rest.

Conclusion

Fire safety in cultural heritage buildings is a discipline that demands humility about the limits of prescriptive regulation and rigour in the application of engineering analysis. The buildings are irreplaceable. The contents, in many cases, even more so. The challenge is to develop fire safety strategies that are simultaneously effective, heritage-compatible, and genuinely calibrated to the full spectrum of what is at risk — including the works of art that are, in the end, the reason these buildings matter.

For facility managers and technical directors operating in this environment, the key takeaways are clear: engage FSE specialists with specific heritage experience, define collection protection as an explicit objective from the outset, and ensure that the models being run are actually capturing the phenomena — heat and soot — that will determine whether your collection survives a fire event intact.

The prescriptive code sets a floor. In a museum, the floor is not enough.