Advantage Engineering – share the experience Fire protection in historical buildings and museums Detection, alarming, evacuation, extinguishing www.siemens.
Contents 1. Introduction ...................................................................................................................................................... 4 1.1. Executive summary ...................................................................................................................................... 5 1.2. Buildings in focus ......................................................................................................................................... 7 1.2.
.2.5. Kitchens.................................................................................................................................................. 26 3.2.6. Electrical plant rooms ............................................................................................................................ 26 4. Alarming, smoke control and evacuation ...................................................................................................... 27 4.1. Introduction .................
Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Historical building......................................................................................................................................... 7 Museum ........................................................................................................................................................
1. Introduction Historical buildings represent a significant part of our cultural heritage as they shed light on the building techniques, artistry and even the way of life in a particular period during the history of a region or country. In many cases, however, the contents of the buildings may be of considerably more significance than the fabric of the buildings themselves; these include museums, art galleries, libraries and archives.
1.1. Executive summary This document provides an overview on the necessity and difficulties of providing adequate fire protection in historical buildings and museums. A comprehensive fire protection system is essential to ensure personal safety and damage mitigation in case of fire. New museums and libraries will automatically be built to comply with the local standards, codes of practice and insurance guidelines.
Extinguishing As these buildings are open to the public they must be equipped with the standard firefighting equipment designed to suppress incipient fires at the earliest possible stage. An adequate number of hand-held fire extinguishers must be provided and situated in easily visible locations throughout the building.
1.2. Buildings in focus Within the scope of this document, we are concerned with the protection of a wide range of buildings. In some cases the buildings themselves are the focus of our attentions, while in other cases it is the contents of the buildings that demand our full attention. 1.2.1.
Modern buildings are designed to provide maximum protection and enable all occupants to exit the building quickly and safely. However adapting a historical building is a much more difficult undertaking and a great many museums are still housed in historical buildings. It is estimated that less than 20% of museums are modern, purpose-built structures, where the appropriate fire-protection building codes have been observed.
1.3. Fire damage costs Damage caused by fire is not a new phenomenon. Over the centuries considerable losses have been suffered and this has been continuing until the present day.
Date Building Country Estimated damage (€) 09.2009 Schloss Ebelsbach Germany 3.5 m Arson 08.2009 South Dakota Library USA 11 m Sparks from concrete saw 04.2008 Castello di Moncalieri Italy 10 m Renovation work 04.2008 Québec Armory Canada 02.2008 Namdaemun Gate South Korea 10.2007 Armando Museum, Amersfoort NL 04.2007 Georgetown Library, Washington DC USA 08.2006 St.Petersburg Cathedral Dome Russia 10.2005 Nuremberg Transport Museum Germany 30 m Unknown 09.
1.4. Causes and challenges The COST Action C17 report: “Built Heritage: Fire Loss to Historic Buildings – The Challenge before Us” by Ingval Maxwell [1] identifies the main causes of fire in historical buildings and the associated challenges that need to be addressed. 1.4.1.
Deciding what improvements should be made requires a structured approach to achieve the above mentioned “balance” and to provide an optimal solution for the particular building in question. To act as a guideline for this decision-making process, the following (generally accepted) criteria have been proposed in the ”Guide for Practitioners 7 – Fire Safety Management in Traditional Buildings” by Stewart Kidd [2].
1.5. Fire safety management The risks to human life and property in historical buildings and museums are relatively high, due to the concentration of people and to the combustible nature of the interior furnishings and fittings frequently present in such buildings. These risks, however, can be drastically reduced by taking appropriate fire protection measures.
A pragmatic approach to this process is detailed in the article “Fire safety and heritage buildings” by Peter Barker [4] and published on the website of the NBS (National Building Specification) - an organization owned by the Royal Institute of British Architects (RIBA).
1.6. Regulations Building owners are often caught between the demands of the fire authorities and those of the conservationists. The primary concern of the fire authorities is the safe evacuation of the building occupants and the provision of adequate fire-fighting equipment.
2. Fire protection in historical buildings 2.1. Fire basics Awareness of how fires start and how they spread can help to reduce the risk of fire quite significantly. It is common knowledge that it takes an ignition source, fuel and oxygen for a fire to occur. The basic fire protection objectives are to try to control all three of these factors: · · · Reduce the likelihood of fire by controlling potential ignition sources Minimize the potential effect by reducing the fire load (i.e.
2.1.2. Managing the fire load Fire risks are largely determined by the fire load of a room or area. The term describes the latent energy which can be released by the combustion of the flammable material within that area during the outbreak of fire: this includes not only the furniture and furnishings, but also the wooden construction of the building itself.
2.2. Fire protection measures Fire protection measures can be divided into passive measures and active measures. Generally speaking, passive (structural) measures define a building's resistance and endurance after a fire has developed, while active measures are aimed at preventing the outbreak and spread of fire and smoke. 2.2.1.
2.2.2. Active measures The limited possibilities of improving passive protection means that even more emphasis must be put on active measures. Active protection can be divided into organizational, detection, alarm and evacuation, and extinguishing measures: Organizational measures During public opening hours the majority of museums and historical buildings will be able to summon professional help relatively quickly in emergency situations.
In addition to the type of alarm and evacuation system provided, evacuation plans, escape route identification, emergency lighting systems and smoke venting systems (where feasible) are essential to ensure a fast and safe evacuation of all persons. All buildings which are open to the public must have a detailed evacuation plan with detailed procedures for the systematic, safe and orderly evacuation of the building in case of fire or other emergencies.
3. Fire detection 3.1. Basic considerations The earlier a fire is detected, the more time there is for evacuation and firefighting, and the less damage can occur. Earliest possible detection is thus the key to minimizing damage and gaining precious intervention time. This is particularly true for historical buildings where fires can spread very rapidly, making fire suppression considerably more difficult.
3.1.3. Deceptive phenomena A fire detector has the task of detecting fire from fire aerosols, heat and radiation at an early stage and triggering an alarm. Aerosols, heat and radiation, however, are also generated by production processes, by electrical equipment such as motors, or by environmental factors such as sunlight. If these deceptive phenomena are sufficiently intense and exist over a certain period of time, they may influence fire detectors enough to trigger an unwanted alarm.
3.2. Fire detection in historical buildings We are often confronted with a historical building that does not yet have an automatic fire detection system installed. However, bearing in mind the life safety aspect and the underlying need to protect cultural heritage against fire damage, installation of such an automatic fire detection system must be considered a high priority. However, to allay the fears of the conservationist we need to adhere to the principles of minimal invasive detection. 3.2.1.
Linear smoke detector In historical buildings and museums there are many rooms with high ceilings. Any room where the ceiling height is 6 m or more is the perfect application for linear smoke detectors. Such devices can cover distances of up to 100 m. They generally contain an infrared transmitter and detector in the same housing, with only a reflector required on the opposite wall, which greatly simplifies the installation process.
3.2.3. Archives and storage vaults Archives and storage vaults may house various different types of object; depending on the building itself (e.g. documents, manuscripts, works of art, archaeological finds, etc.). These are risk areas that need to be especially well protected, particularly from the danger of fire.
3.2.5. Kitchens Large cooking vessels, frying pans and deep fryers, present a very serious fire hazard in commercial kitchens. This is mainly due to the strong possibility of fire breaking out due to overheating and to the local high fire load. Multi-sensor fire detector with a smoke/heat combination and sophisticated signal processing are recommended for monitoring these areas.
4. Alarming, smoke control and evacuation 4.1. Introduction Once a fire has been detected by an automatic detector, by sprinkler flow monitoring or by a person activating a manual call point, the fire detection system will generate the preprogrammed control and alarm signals. A major factor that can affect the success of building evacuation is that many people do not take the sounding of a fire alarm sufficiently seriously or do not understand the meaning of the acoustic signal.
4.2.3. Alerting visitors Visitors can be warned of the impending danger in several ways. Acoustic alarms Electronic sounders are regarded as the normal means of raising an alarm and are suitable for most applications. The recommended sound level of such devices (according to EN54-3) should be not less than 65 dB(A) or 5 dB(A) above the ambient noise level.
4.2.5. Alarm strategies General alarm A general alarm is a defined audible signal which is sounded throughout the building. The alarm is automatically activated by the fire detection system, or manually from the admission desk (or security manager’s office). In the majority of historical buildings this should trigger the immediate and total evacuation of the building. Staff alarm When the first signs of an incipient fire are detected, only members of staff are initially informed.
4.2.6. Alarm Verification Concept AVC Figure 15 Alarm Verification Concept The Alarm Verification Concept (AVC) allows in-house personnel to carry out a local investigation before the municipal fire service is alerted or the building is evacuated. This reduces the number of unnecessary calls and is based on a dual timing principle. It is only applicable to the “day/manned” mode of the fire detection system.
4.3. Smoke control 4.3.1. Objectives Smoke presents the greatest danger to life in the case of a fire. This is not only due to smoke inhalation injuries and asphyxiation, but also due to smoke-filled corridors and staircases, which make evacuation considerably more difficult and raise panic levels. Smoke may also cause considerable damage to room furnishings, paintings or other artifacts on exhibition.
Hidden voids One of the greatest threats of smoke and fire spreading in an uncontrolled manner throughout historical buildings is the presence of unknown voids, ventilation shafts and unused service shafts. As a minimum any connected voids should be blocked off to ensure that defined fire compartments are maintained. In some cases it may actually be possible to utilize the unused flues and ventilation shafts for smoke extraction purposes, without detrimental impact on the aesthetics of the building.
Conducted evacuation (staff alarm) In buildings where a large number of visitors may be present, who are not familiar with the building layout, it is important to avoid any panic that might occur in a simultaneous evacuation. Conducted evacuation is a strategy that relies on well-trained staff and carefully planned evacuation procedures: · · · · Phased evacuation (staged alarm) Members of staff are warned as soon as an initial fire alarm has been triggered.
4.4.4. Evacuation instruction The single most important factor in a successful evacuation is providing people with clear instructions telling them what they have to do. In such environments it is generally considered inadequate to rely on the visitors being able to correctly interpret the meaning of the acoustic ‘alert’ and ’evacuate’ signals from simple sounders.
Figure 16 Exit route sign The problem with this type of sign is that they may not be easily visible in smoky conditions. For this reason the concept of way guidance is becoming more widespread in new buildings. Way guidance To complement emergency escape signage, way guidance equipment can be very useful in helping people to follow exit routes.
5. Extinguishing 5.1. Introduction Although preventing the outbreak of fire is the highest priority, the possibility of a fire occurring will always remain present. An automatic fire detection system, as discussed in Section 3 must also be supplemented by an effective fire extinguishing infrastructure.
5.3. Extinguishing systems The most appropriate automatic extinguishing systems for historical buildings and museums depend to a large extent on the application. · · In general exhibition areas o Sprinkler systems o Water mist systems In archives, closed storage vaults and electrical plant rooms o Gas extinguishing systems o Extinguishing systems using gas/water-combined technology 5.3.1.
this way an incipient stage fire can be suppressed at its source as only those sprinklers in the immediate vicinity of the fire will be activated, minimizing any unnecessary water damage. Currently several premiere cultural heritage institutions have installed, or are in the process of installing, complete automatic sprinkler protection. Examples include the Library of Congress, the Smithsonian Institution, the National Library and Archives of Canada and the National Library of Scotland.
5.3.3. Gas/water-combined systems An alternative to the pure gas systems can be provided by proprietary systems using a combination of gas and water mist. Releasing additional N2 gas into a closed room, where an embryonic fire has been detected, effectively reduces the oxygen concentration in the room and extinguishes the fire, while the water mist cools the combustible material and prevents re-ignition.
Class of Fire Extinguisher Type A B C D F Solids Liquids Gases Metal Cooking oils Water Yes No No No No Foam Yes Yes No No No ABC Powder Yes Yes Yes No No Dry powder (Metal Fires) No No No Yes No CO2 No Yes No No No Wet chemical No No No No Yes Figure 18 Fire extinguisher applications 5.4.2. Fire hose reels Fire hose reels are often overlooked or discarded as a possible option in favor of portable fire extinguishers.
5.5. General recommendations The research report “Manual Fire Extinguishing Equipment for Protection of Heritage” by Geir Jensen [5] (published in support of the COST Action C17 “Built Heritage: Fire Loss to Historic Buildings”) provides the basis for a number of the recommendations made in this section. It is reasonable to assume that exhibition objects themselves are not generally the source of an embryonic fire.
5.5.1. Areas requiring special attention When planning the extinguishing concept for a historical building or museum, the following areas should be given special attention: · · · Archives Electrical plant rooms Kitchens Archives A system employing a combination of gas and water mist can provide an effective solution for archives and storage vaults, in which documents, manuscripts, books or paintings are stored.
Technological investigations have shown that malfunctions can occur in hard disk drives when automated dry extinguishing systems are activated. These malfunctions range from automatic shutdowns to more severe disturbances, with a corresponding loss of data. Studies by independent organizations concluded that it was primarily the high noise level generated by conventional extinguishing systems during the discharge process, which caused the hard disk drive malfunctions.
6. Advantage Engineering – share the experience With our dedicated program for consulting engineers, you can benefit from our extensive application know-how and complete portfolio. With Siemens, you can offer your customers comprehensive fire safety for any application and environmental condition. Your customers will appreciate this as it enables them to reliably protect people, assets and business processes from fire.
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46 Siemens Switzerland Ltd Building Technologies Division
Siemens Switzerland Ltd Building Technologies Division International Headquarters Gubelstrasse 22 6301 Zug Switzerland Tel +41 41 724 24 24 The information in this document contains general descriptions of technical options available, which do not always have to be present in individual cases. The required features should therefore be specified in each individual case at the time of closing the contract. The document contains a general product overview. Availability can vary by country.
