Protecting our history from fire, by learning from the past

Put simply, fire is probably the single most obvious common threat to the fabric and contents of sites that represent our cultural heritage. We all hope to learn from the historical buildings and museums that are all around us and much effort goes into conserving them. However, one thing that life has taught us is that while a fire in an ordinary building might sometimes cost a great deal of money to rectify, the loss of irreplaceable works of art or the damage to historically significant sites are things that often cannot be put right.

As the current custodians of these historic buildings, artifacts and all the works of art contained within our galleries, museums, stately homes, churches, castles and palaces, it is our duty to take care of them so that they can be enjoyed by generations to come. Of course, there are many aspects to providing adequate protection but we must surely give a particularly high priority to safeguarding them from fire.

Often it is the building or site itself that is of notable, historical significance. Perhaps an important event took place there that changed the course of history and the lives of local people forever. Or perhaps the building shows the way of life of times gone by – the architecture, the building methods, the quality of the craftsmanship. In instances such as these, it is the protection of the building itself that is of prime concern. In other cases, such as our municipal galleries and museums, it is the many paintings, sculptures, artifacts and objets d’art that must be defended against the ravages of smoke and flame. Often it is both. However, one factor which is more important than all of these considerations when it comes to installing the most suitable fire protection systems possible – the protection of human life.

Human life is always the first priority

With so many visitors and staff regularly upon the premises of historical buildings, museums and galleries, it is naturally the duty of the buildings’ owners and management to provide the best possible around-the-clock fire protection for the site and the people using it. It is vital to minimize the likelihood of fire by the elimination of major risks and careful management of those risks that cannot be eliminated. This usually involves the implementation of not only the appropriate infrastructure of fire detection, alarming, evacuation and extinguishing systems, but also the requisite management of staff training, fire drills, as well as the strict adherence to maintenance schedules and the observing of all fire-safety regulations.

Recently designed and constructed museums and galleries – like all modern buildings – should be designed to comply with all current national legislation in order to provide the maximum protection of all their occupants against fire at all times of night and day. In the event of a fire, all the people within the building should be alerted to the danger and able to quickly and calmly exit the premises through a clear, well planned and safe exit route. These modern galleries and museums will be designed with compartmentalization to contain any spreading of fire. They will also probably feature: state-of-the-art fire detection and alarming equipment: smoke control ventilation; multiple, well signposted emergency exit routes; and extinguishing systems appropriate to the objects thatare being protected.

However, it is generally estimated that less than 20% of galleries and museums around the world are this kind of modern building. Many works of art and items of historical, artistic or natural significance are usually housed in older civic buildings or institutions and these older buildings are naturally made with the traditional, easily combustible materials in common use at the time of their construction. Adapting existing older buildings to provide such comprehensive cover is often a difficult undertaking.

The challenges

The potential impact of fire on items and sites of historic importance is, ironically, not a new thing. Loss of historically significant documents and artifacts has happened throughout recorded time – ever since the fire which reputedly destroyed the Library of Alexandria, one of the largest and most significant libraries of the ancient world. More recently many fires such as those at the Quebec Armory in Canada and Windsor Castle in England – the largest inhabited castle in the world and one of the official residences of the British monarch – have caused major damage to the buildings and the artifacts they housed.

Often, the electrical systems within historical buildings do not comply with today’s safety standards and consequently are an inherent danger themselves, but sometimes it is simply the negligent and careless use of electrical equipment and appliances that can be shown to be the cause of many outbreaks. This includes heating equipment, spotlights, hot-plates, toasters and coffee-makers left switched on, or welding, soldering or brazing work taking place during renovation projects. The spread of any resulting fire and the extent of the damage caused are often exacerbated by the traditional construction methods and standards relevant to the period in which the building was constructed. Adverse factors facilitating the spread of smoke and flames might include: open and ill-fitting doors; thin walls; structural discontinuities; unknown wall and floor voids; unstopped ventilation and service routes; undivided roof voids and the general lack of compartmentalization.

Providing protection of people and cultural assets

Providing optimal fire protection for both the people and the property itself is often at odds with the conservationist ideals of minimal intervention regarding the structure and aesthetics of any building of historic importance. The challenge for providers of fire protection is to find the balance between safeguarding life and maintaining the historical authenticity of the site. The need to preserve the aesthetic look and feel of the site is a challenge in itself. Retaining the integrity of irreplaceable interior architectural details such as wall decorations, stucco ceilings and frescoes, is vital. Finding the optimum solution is the key to providing an effective fire safety concept for each building.

Museums and galleries often have large exhibition rooms with high ceilings. In these instances, the deceptive phenomena that sometimes occur in other locations – such as steam, dust or smoke from sources other than a fire – are generally unlikely to be present. But the large volumes of air in these rooms will cause the concentration of any genuine fire-related aerosol to be greatly diluted and more difficult to detect as a result. Such a situation calls for a proactive detection system with high sensitivity – a term which perfectly sums up ASD (Aspirating Smoke Detection) technology. ASD systems ensure reliable fire detection in demanding application areas and, combined with innovative extinguishing systems that cause no damage to the priceless, irreplaceable, sensitive items being protected, are often the ideal solution.

Being very sensitive to the lowest concentrations of smoke, ASD provides the earliest possible detection of the outbreak of fire. It works by drawing air to be sampled in a detection chamber through a large number of small holes in a network of concealed pipework that can be made practically invisible to the naked eye. In highly ornate locations, such as the artistically decorated ceilings and walls of churches, cathedrals, theatres and libraries, ASD can provide what is effectively invisible fire detection with the pipework hidden in roof voids to detect smoke early and reliably, well before active flaming breaks out. In this type of application, characterized by high ceilings and large open areas, smoke stratification will occur, mainly because smoke from a small fire lacks the heat and subsequently the thermal buoyancy to reach mounted beam type or conventional detectors located high on the ceiling. ASD uses innovative optical dual wavelength technology to detect the earliest signs of combustion, whilst ensuring good immunity to those deceptive phenomena. Doing so enables detection of smaller airborne particles as produced in the earliest stages of overheating or as found in open fires. By determining the size and concentration of the airborne particles, aspirating smoke detectors are able to differentiate between smoke and dust and steam particles. As a result, they offer the highest detection reliability, preventing the downtime and loss of income caused by false alarms. To meet the requirements of challenging environments, the detectors have a programmable sensitivity range so that not even the most demanding conditions will provoke a false alarm.

The main priority in some historical buildings however, is often the need to minimize the impact of the detection system on the decor, aesthetics and the structure of the building, both during the initial installation work and during any subsequent maintenance. Where ASD would therefore prove unsuitable, other intelligent solutions need to be considered – such as a combination of wireless and linear smoke detectors – which is specifically suited to the needs of protecting buildings and items of historical or cultural value.

Maximum protection with wireless technology

Needing no cable, radio fire detection is the ideal solution for rooms or buildings with aesthetic or architectural restrictions as well as temporary installations. As the technology is wireless, devices can be quickly positioned and repositioned. This facilitates planning, reduces the costs of installation and offers a high level of freedom and flexibility should room or building usage change at any time. Solutions are available which use mesh technology, along with detectors to eliminate false alarms and still provide early detection. Mesh technology is especially helpful in overcoming obstacles like the very thick walls which are typical of historical buildings or when setting up large wireless networks

Detectors with two optical and two heat sensors are more reliable than conventional wireless smoke detectors. The capacity to adapt to the appropriate environmental conditions is also important – from ‘Clean’ to ‘Harsh’, for example – by choosing an application-specific parameter set. Technology can interpret and evaluate signals in real time, dynamically adapting the selected parameters. This means the detector is immune to those deceptive phenomena such as steam, dust or even the special effects sometimes used in theaters.

Such a wireless fire alarm system has recently been installed to protect and preserve the historically valuable interior of Tettnang Castle, the stately residence of the Counts of Montfort-Tettnang in Germany’s Upper Swabia region, filled with impressive art and stuccowork from the 18th century. The Castle features spectacular Baroque interiors which are still among the finest in the region. Thanks to the intelligent and safe wireless technology, the original building structure remained untouched and the solution was installed quickly without interfering with the museum’s opening hours.

Alarming and evacuation measures

If a fire should break out, it is essential that all staff and visitors are promptly and efficiently made aware of the fact. Visitors to historical sites, galleries, museums and other buildings of historical or cultural interest, will often include families and older, less mobile people who must all be evacuated safely and effectively in order to protect lives. These types of attraction will often have many hundreds of visitors and must usually fulfill special requirements with regard to alarming and evacuation in the event of a fire. Those places with such large numbers of visitors will need bells and alarms with a higher noise level but should also be equipped with optical alarms or beacons and sounders for the hard of hearing and partially sighted. The obvious purpose of the acoustic and visual alarms is to warn both visitors and staff of the hazardous situation that is potentially developing. It also signals the need for trained staff to take their place in order to coordinate the evacuation and help all visitors who are probably unaware of the planned escape routes and emergency exits, to exit the building safely. In some cases, the alarm will also call some specially trained staff to investigate the cause of the alarm and possibly tackle the fire with the appropriate hand-held extinguishers if they can do so without endangering themselves and others. Alarms intended for in-house staff should always be generated without delay in order to allow the cause of the alarm to be investigated as quickly as possible. Members of staff may be alerted without activating the main alarm to investigate whether the fire is small enough to be tackled without disruption to visitors and normal business activities unless absolutely necessary. Staff may be contacted by pager, mobile phone, the app on a smart phone, a local, discreet audible alarm or even a silent or coded alarm.

At the very least, a basic system will activate the installed alarms and transmit a signal to the local fire department and emergency services. More sophisticated solutions may include a dedicated voice alarm system providing clear and concise information through calm, pre-recorded vocal messages to assist a speedy evacuation and to prevent panic.

Extinguishing

Whatever systems or solutions are put in place, with so much activity taking place on the premises of historical buildings, galleries and museums – involving not only visitors but also catering, electrical repair and maintenance staff – the possibility of a fire gaining hold will always be present. The high fire load of these buildings, along with the difficulties of ensuring effective compartmentalization, means that a fire can soon gain hold if it is not stopped in its early stages. The provision of an adequate number of hand-held extinguishers in the appropriate areas to be operated by staff or competent visitors in the earliest stages of an outbreak is essential. Intervention by municipal firefighting forces might prevent the total destruction of the building itself but the amount of water used from high-pressure hoses during the rescue process sometimes results in as much water damage to important artifacts and works of art as that caused by the fire and smoke. The installation of an automatic extinguishing system is the obvious answer to this problem but so many sites of historical and cultural interest simply have not taken this important step.

There are, of course, various different forms of automatic extinguishing solutions, the suitability of which largely depends on the application itself. In general exhibition areas, water sprinkler systems and water mist systems are mostly used for their effectiveness, high reliability, their simple and robust technology, low maintenance costs and the usual plentiful supply of water. The use of sprinkler systems is primarily intended to protect the fabric of the buildings and prevent their collapse. The sprinklers can effectively suppress and extinguish fires in the early stages of combustion, but their main purpose is to control the fire and cool the building structure in order to allow firefighters to tackle any real blaze by reducing smoke and dangerous gases and lowering the internal temperature. However, the installation of sprinkler systems, common in modern buildings and often required by local building regulations in many countries, can substantially reduce the insurance premiums for many premises. However, this is often frowned upon in historical buildings and museums by conservationists. The installation procedure can be quite invasive and should only be undertaken where architectural or interior decor sensitivity is not an issue.

In archive rooms and closed storage vaults where historic or artistic items are housed, gas systems or those using a combination of inert gas and water are widely employed. Inert gas systems are particularly suitable for rooms that contain sensitive objects or equipment where water cannot be used. However, an alarm must be sounded before the release of the extinguishing gases – which suffocate the fire by depriving it of the oxygen needed for combustion – to alert people of the imminent flooding of the area. Unique systems using a combination of gas and water admix release nitrogen gas to reduce the concentration of oxygen in a room and effectively extinguish detected fires, rapidly and reliably. The release of water admix cools the combustible materials to prevent re-ignition and also serves to provide a smoke scrubbing function, thus reducing the health hazard facing people as they re-enter the room.

An intelligent approach to fire safety in historical buildings and museums

The protection of historical buildings, galleries, museums, theatres, libraries and other buildings of cultural interest from fire is unlike that required by most other types of building. They generally comprise many different types of room: large display rooms with high ceilings; archive rooms and storage vaults housing different types of important objects and documents; electrical plant rooms in which power supply equipment, control systems, security systems and computer servers are accommodated; kitchens that cater for large numbers of visitors and staff daily represent a potential fire hazard; special function rooms used for receptions, parties, weddings and conferences. These areas can all be considered as relatively critical zones due to the difficulties in detecting the early stages of combustion or the variety of ignition sources. Simple compliance with the relevant minimum legislation does not always provide comprehensive protection from the damaging effects of fire, smoke – and the high-pressure water used by firefighters to suppress their spread – especially in terms of protecting the valuable assets and irreplaceable historic artifacts and works of art.

The Polish Maritime Museum in Gdansk, the largest museum of its kind in Poland, is a good example of how a fire protection system can be tailored to meet the specific needs of a given application. The main building, the Granaries on Ołowianka Island, was built in the late Middle Ages and now hosts extensive exhibitions of original historical objects, stored on both a permanent and temporary basis with thousands of visitors each year. Linear smoke detectors were installed in the two-level exhibition halls and the atria, along with loop-powered sounder beacons to ensure fast and safe evacuation. To avoid interruptions of normal museum operations, the work had to be completed in a very short period of time.

For more information, go to www.siemens.com/firesafety