Cultural heritage fire safety

Due to the speed and totality of its destructive forces, fire is one of the main factors of vulnerability for historic and cultural buildings. Museums, libraries, archives and other places housing works of art are vulnerable to fire due to a combination of several factors: large building size, interconnected spaces, flammable materials of inestimable value and existing structures with low fire resistance. In addition to this, risk prevention actions must not conflict with the protection of the property and the aesthetic value of both the heritage and the context in which it is located, making this mission complicated.

The ‘Cultural Heritage Fire Safety’ event, held on 5 October and organized by the ISA – Istituto Superiore Antincendi – with the Order of Engineers of Rome, focused on the fire safety of cultural heritage with a comparison between European technical regulations and NFPA standards. In addition to the NFPA representatives, the event was attended by the Italian Ministry of Culture (MIC) through the General Directorate for Cultural Heritage Security, National Fire Brigade, CEI and the SAFEng PC – Firtech representatives.

American and Italian regulations

The NFPA is the main organization which studies and regulates all fire-related hazards in the United States, with the mission to eliminate death, injury, property and economic loss from fire, electrical and other hazards, and to develop easy-to-use educational programmes, tools and resources for all ages and audiences. Through the NFPA website, more than 300 ‘rules’ are available in free read-only mode and every person can see what has been done by the technical committee, as the documents are made available online (Fig. 2).

Figure 2: NFPA ecosystem and code development process.

Regarding cultural heritage, the NFPA proposes the following codes:

NFPA 909, Code for the Protection of Cultural Resource Properties – Museums, Libraries and Places of Worship. This code describes principles and practices for protecting cultural properties (such as museums, libraries and places of worship), their contents and collections against conditions or physical situations with the potential to cause damage or loss.
NFPA 914, Code for the Protection of Historic Structures, which describes principles and practices of fire safety for historic structures and for those who operate, use or visit them.

Among the various codes for fire prevention and management, there are some specific codes for cultural buildings also in Italy. In recent years, Italy has adopted a mixed approach based on performance and prescriptions, which allows many problems to be solved. The Fire Prevention Code represents a revolution in the Italian regulatory landscape, as it represents a unified text that can be uniformly applied. In relation to cultural heritage, the Code contains the Vertical Technical Rules RTV V.10 – Museums, Galleries, Exhibitions, Libraries and Archives and RTV V.12 – Other Activities in Protected Buildings¹ (Fig. 3). In addition, the previous planning of maintenance and control operations of the structures, such as the evacuation plan of the building, is fundamental for the safeguarding of the sites.

Figure 3: The Fire Prevention Code, Activity 722: Vertical Technical Rule (RTV V.10 - V.12). — Figure 3: The Fire Prevention Code, Activity 722: Vertical Technical Rule (RTV V.10 – V.12).

The General Directorate for the Safety of Cultural Heritage also contributed to the discussion. A key aspect on which the Directorate works is the development of research projects, including the SAFEng project, that can create new solutions for the protection of cultural sites. Technological innovation supports the implementation of security systems that can help overcome discrepancies between security requirements and protection restrictions.

The SAFEng PC project

SAFEng PC is a scientific and industrial research project applied to the protection of cultural heritage from the dangers of fire. The project stems from the desire of Tema Sistemi S.p.A. to use its know-how to create a specific firefighting system for protecting museums and buildings of historical interest. For this project the company, specialized in the design, production and maintenance of certified firefighting systems and products in the industrial, civil and naval sectors, together with the innovative start-up Firtech, created ad hoc to follow experimental projects on cultural sites, is collaborating with the University of Ferrara, the National Fire Brigade and Ferrara Fiere Congressi. Some sites for experimentation and fragments of artistic materials were made available by the MIC: during 2021, inspections were carried out at the Ducal Palace in Mantua, the Royal Palace of Caserta, and the Marucelliana Library in Florence to assess and select representative spaces for experimentation.

Although the project is based on prevention and protection from a specific hazard, its results are multilateral involving various aspects which consider the general protection of assets starting with the study of materials, interaction with the surrounding environment, reaction to fire, smoke and extinguishing agents.

To achieve the objectives, preliminary research was necessary, starting with the study of existing guidelines for the conservation and protection of art works, as well as the experimentation of protocols to evaluate suitable systems for the protection of cultural heritage. These tests are part of a further project involving Galleria Borghese in Rome, the Department of Chemical Engineering Materials Environment of the University ‘La Sapienza’, Tema Sistemi and Firtech for the study and evaluation of a watermist system suitable for the museum storerooms conceived as a real picture gallery. The first step in the development of these two projects involves guidelines evaluation on the parameters for the conservation of cultural materials and the use of extinguishing systems and agents. Therefore, bibliographic research was conducted for a reflection on the state of the art of the regulations and methodological tools developed for the protection of cultural heritage, regarding physical parameters such as humidity, temperature and wettability of surfaces, related to natural and/or man-made disasters. The research highlighted limited guidelines useful for safeguarding tangible cultural heritage following accidental and/or emergency events, which require the use of products that can drastically change the environmental conditions of the property and its ‘historical climate’: in fact, cultural heritage is made up of different materials with certain physical and chemical characteristics; however, the regulatory framework does not contain analytical studies on cultural heritage materials following the use of extinguishing systems and no low-impact strategies are proposed. On this basis, the next phases of the project involved the study of the interaction between the proposed system and certain historical materials.

Two test protocols were studied and developed: the first one to evaluate the humidity following the watermist system’s application on the works of art, the second one to verify the fire control and the contextual protection from fire and smoke damages.

The aim of the humidity test is to determine the humidity amount deposited on the surface of the sample following the application of a watermist system. Canvas samples, paintings, and frames (Fig. 5) were used to develop the test. The samples, provided by the Galleria Borghese Museum, were previously analysed to study their composition and state of conservation.

Figure 5: Samples used for the humidity test: canvas fragments, painting, and gilded frame.

The watermist system used consists of a high-pressure pumping unit and a nitrogen mixing unit, which enables the atomization of water droplets, emitted through open-type nozzles. During the test, the system was activated at an operating pressure of 65 bar for 15 minutes within an experimental scenario (Fig. 6) represented by a room in which a nozzle was placed in the centre of the ceiling and samples were placed on the walls at two different heights. For each sample, the moisture content was measured with results that met expectations and with moisture values that caused no damage to the materials.

Figure 6: experimental scenario during the humidity test.

The fire test protocol was formulated to evaluate the effectiveness of the watermist system during a fire simulation. The system used was the same as that described for the previous test, while the samples used are three paintings and a plywood support with two pieces of frame and four pieces of canvas, positioned on the wall at different heights. The representative volume of the scenario was constructed with 12mm-thick plasterboard walls and ceiling attached to support structures. Inside the room, a wooden table was placed against the wall on which the samples were affixed, with liquid and solid materials representing the source of the fire (Fig. 7).

Figure 7: Experimental scenario plan; liquid and solid materials representing the fire source.

These materials were characterized in terms of combustibility and flammability for the complete characterization and definition of the characteristic fire curve, which is the first objective of the test. Furthermore, to standardize the test and ensure the replicability of the results, the actual fire curve was derived ex post from a pre-test phase in which the selected materials were ignited in the same test room to map the values of the characteristic parameters that allow the actual fire curve to be estimated (Fig. 8).

Figure 8: Temperature and combustion gas trends during the pre-test phase.

During the test, in addition to data on the fire extinguishing system, temperature data were acquired by means of thermocouples, humidity before and after the test, and gas measurements for the evaluation of the system in relation to the conservation of the works of art.

Figure 9: Experimental scenario during fire test.

The test based on this protocol was held in the presence of a Certification Body: the results met expectations and the data will be processed by ‘La Sapienza’ University for the engineering part, while the samples were sent to the University of Ferrara to compare the data obtained before the tests to verify changes in the state of conservation of the materials.

The results obtained from humidity and fire tests, with the relative analysis of the samples before and after the tests, represent the basis for the experimentation on the three real sites mentioned above (Fig. 10), starting with the Ducal Palace in Mantua. The selected room, belonging to the ‘Apartments of the Tapestries’, was reproduced on a full scale to test the watermist system during the fire test, according to the parameters established in the previous protocols. The same procedure will be applied to two other selected sites, the Central reading Room of the Marucelliana Library in Florence and Gioacchino Murat’s bedroom in the Royal Palace of Caserta, for an evaluation of the system’s effectiveness in real contexts characterized by different types of assets and structures.

Figure 10: Representative sites selected: Marucelliana Library, Ducal Palace in Mantua, Royal Palace of Caserta.

To summarize, given the insufficient information on the appropriate parameters for selecting a fire protection system suitable for cultural sites, specific test protocols were formulated for a watermist system: the humidity test and the fire test aim to assess the impact that this system can produce on artistic materials, in order to be able to present a product that is not harmful to cultural heritage at the end of the experimentation. SAFEng therefore wants to show a paradigm shift by studying, analysing and proposing specific solutions for the simultaneous protection of people, works of art and the environment. Regarding this last aspect, the project, through the study of a new watermist system, allows a water saving equal to 90% compared to traditional systems, developing devices of reduced sizes that involve the use of completely recyclable fewer materials. The project contributes to achieving the objectives of the Horizon Europe programme and the ONU 2030 Agenda to reduce resource consumption and mitigate the impact of climate change.

Figure 11: Sustainable goals of the project.

Conclusion

The protection and management of cultural heritage remains a great challenge in the fire-safety field. Significant progress has been made in recent years from a regulatory point of view, also in relation to the divergence between the need to protect cultural buildings and the aesthetic respect of historic structures and materials. Among the significant issues to be addressed in safety management and planning are the architectural and construction characteristics of buildings, the damage that fire and heat can cause (rapid oxidation, soot deposits), as well as water damage (rot, weaken and warp wood and other organic materials, rust, mould, corrosion or general deterioration) and chemical damage (fire products such as smoke, vapours, etc., with the formation of chemicals that can corrode, dissolve, weaken or stain objects), structural failure and human impact, such as wrong handling due to the evacuation of works of arts.⁴

The SAFEng project fits into this context by creating new opportunities to safeguard invaluable heritage, offering new data and products to improve the field of fire protection of historical buildings, people and the environment. To overcome the challenges in this field, continuous progress in the direction of research projects, technological innovation and knowledge transfer to industry and specialised professionals is essential.

References

1. Decree July 10th, 2020 (GDL for RTV 10 Decree of the Head of the Corps 22/12/2017 No. 209) and Decree October 14th, 2021 (GDL for RTV 12 Decree of the Head of the Corps 16/4/2019 No. 140).

2. Annex I to D.P.R. No. 151, August 1st, 2011.

3. D.M. 467 25/10/2018 Decree of extraordinary program of the funds coming from the OPs/ ERDF 2017-2013 and subsequent remodulation.

4. Conti, M. F., ‘RTV 12. La prevenzione incendi negli edifici sottoposti a tutela contenenti una o più attività soggette’, Antincendio, October 2022,12-29.