Agent of Deterioration: Fire
Table of Contents
No institution is immune from the risk of fire. Unlike other agents of deterioration covered in this book, serious damage or total loss of the building, collections, operations, and services can occur. Personal injury — or even death — may also occur. As a result, it is important that fire prevention and fire control be given the highest priority possible. As well, every effort should be made to reduce the risk of a fire from occurring and to minimize its effects. While the cost of doing so may seem prohibitive, the cost of doing nothing may be even greater.
Because life safety issues are under the jurisdiction of government authorities, they will not be covered in this chapter. Instead, this chapter will look at fire safety and protection from the perspective of preserving and protecting cultural property, and collections in particular. While many museums may meet basic requirements for life safety, too often these requirements are inadequate to protect cultural property.
Brief Fire Theory: Principles of Combustion
Fire is the state of combustion resulting from a chemical reaction that requires the presence of three elements in proper combination — a fuel source (anything that burns), oxygen (a component of air), and an ignition source such as heat or a spark — in order to begin and develop. This is often referred to as a "Fire Triangle," as shown in Figure 1.
Extinguishing a fire usually involves removing at least one of these elements.
The following briefly describes the various stages of fire.
Main Stages of Fire Development
Fire remains limited in size initially, and can be easily extinguished using a portable fire extinguisher at first. Detection may not occur until flames become visible or when heat is produced. Sprinklers will activate when sufficient heat is produced at the ceiling. Sprinklers will control and possibly extinguish the fire. Fire will become uncontrolled if an automatic suppression system is not provided. This may lead to the next stage.
Heat becomes intense and high enough to ignite common combustible materials within the room, leading to a fully developed fire. This can happen within minutes of the pre-flashover stage when the proper conditions are in place.
Fully developed phase of a fire, whereby all exposed combustibles in the room are involved. This may result in total loss of collections within the room; the entire building is threatened. Flames may spread to other rooms through hallways and ceiling voids. Fire will eventually burn out when all combustibles are consumed.
Because fire can grow and spread rapidly, it is important to detect and extinguish it at the earliest stage possible in order to reduce the risk of serious damage, injury. or loss.
Sources of Fire Ignition
While museums and related institutions are vulnerable to fire from a number of different sources both inside and outside the building, most museum fires begin as a result of human neglect and carelessness, or are intentionally set.
Some typical sources of ignition include:
- exterior and natural sources such as lightning, proximity to forest, bush or grass fires, exposure to adjacent burning buildings or exterior trash containers, etc.;
- electrical sources such as faulty or overloaded wiring, electrical panels, electrical equipment and appliances, and HVAC system (heating/ventilation/air conditioning) systems;
- proximity of combustible materials to a heat source such as portable heaters;
- open flames such as candles and food warmers used during catered events;
- "interpretive fires" such as fireplaces, cook stoves, candles, blacksmith shops, etc.;
- construction and renovation activities such as hot work (i.e. welding, paint removal, cutting, etc.), the use of casting materials that produce heat, etc.;
- improper use, storage, and/or disposal of flammable liquids such as paint thinners;
- smoking materials;
- gas leaks (Figure 2); and
While collections such as cellulose nitrate film, ammunition, munitions, blasting equipment, flammable liquid ("wet" collections), etc. are usually not the cause of fire, they contribute to the building's fire load, and greatly increase the threat to fire fighters.
Places of worship are particularly vulnerable to arson because they tend to be relatively isolated, kept unlocked for the public's use, and consist of large open spaces and hidden voids that allow fire to spread rapidly. Historic structures sitting vacant or unattended are also highly vulnerable.
Seasonal museums can also be at risk. Because many of these small community museums do not have HVAC system systems, space heaters, portable heaters, and even wood-burning stoves are sometimes used during the spring and fall to help control dampness and to provide heat for staff who may be working in the building. In addition, many small community museums are located in remote locations where acts of vandalism and arson may go undetected for some time, particularly during the "off" season. These museums are often constructed of highly combustible materials, lack monitored fire detection and automatic fire suppression systems, and may not have a reliable water source at hand. Some museums rely on battery-operated smoke alarms; however, it is important that these devices are regularly tested, cleaned, and the batteries changed. While these alarms may suffice in terms of life safety when the building is occupied, during non-working hours, response by the local fire service could be substantially delayed.
Historic house museums are particularly vulnerable to rapid fire growth and can be more problematic to retrofit. Their vulnerability may be due to a number of causes:
- They may be constructed of highly combustible and non-fire resistive materials, which have dried out over time.
- They may still have older heating systems and electrical wiring that is both hazardous and inadequate.
- Many are designed with large open staircases that allow fire and smoke to rapidly spread between floors.
- There may be concealed voids above ceilings, below floors, and behind walls.
- Many have basements and attics that are not compartmentalized.
- Openings around installed or removed ductwork, electrical conduits, plumbing pipes, etc. may not have been stopped with fire-resistive materials where the penetrations pass through floors, ceilings, and walls.
- Cleaning supplies, solvents, paints, waxes, etc. are often inappropriately stored in the basement or in a non-fire-rated closet.
Fire loading from house contents and finishes may be high; and the facility may be used in ways that present additional fire hazards; for example, using fireplaces or wood-burning stoves to heat the museum or for interpretive purposes such as cooking and baking. In addition, the museum may be rented out for film projects or used for special dinners and meetings where open flames such as candles are permitted. In spite of these hazards, many museums do not have a monitored fire detection system or automatic fire suppression system. However, before making changes to the structure to make it safer, or installing or upgrading fire protection systems, it may be necessary to consult a preservation architect who is experienced in undertaking these kinds of projects while respecting and honouring the historical fabric and design of the structure.
Regardless of whether a museum facility is historic, or modern and purpose-built, it is important to know the building and its systems thoroughly and to keep them well maintained. Unfortunately, all too often fire prevention and protection and building maintenance are put aside, as money and staff time are diverted towards other programs and activities. However, by making fire safety a priority, measures can be taken to protect staff, visitors, collections, building(s), and services from loss and harm. Depending on the extent of damage, recovery and re-opening after a fire may take many years, or may even require erecting a new building. Some museums never recover.
Impact of Fire on Collections
Depending upon the type, extent, and severity of a fire, and the vulnerability of items to heat and smoke, damage to collections can range from minor discolouration to total loss.Items located in the seat of a hot flaming fire may ignite and burn completely or partially. Even items located elsewhere, for example in another room, may become distorted, discolored or brittle, or covered with a layer of powdery soot as in Figure 4.
While damage from heated gases and soot may not result in complete loss, extensive and irreversible damage can still occur (Figure 5).
Organic materials from plant and animal products such as paper, textiles, and wood are highly susceptible to combustion, particularly if very dry. In general, the thinner the item, the more likely and quickly it will ignite and burn completely. For example, a single sheet of paper will ignite and burn rapidly, while books packed tightly together on a shelf may remain relatively undamaged except for damage to their spines (Figures 6 and 7), and perhaps soot deposits or discolouration on the head of the books.
While items made from inorganic materials such as stone, glass, metal, and ceramic are not likely to ignite, they can still suffer extensive damage such as melting, warping, discolouration, embrittlement, cracking, and even shattering.
In addition to damage from heat, objects can also be seriously damaged by smoke and soot. Smoke is the product of combustion, and generally consists of fine particulates and hot gases, while soot refers to the finely divided carbon deposited by flames during the incomplete combustion of organic substances. Both are damaging to cultural property.
Soot deposits, such as on the cabinet in Figure 8, typically result in a powdery, ash-like deposit that can dull, or even obliterate, surface images and details. When soot-covered materials are handled, the soot may be further pressed into the surface. Organic materials with porous or highly textured surfaces are especially vulnerable and may be extremely difficult to clean. As a result, soot-damaged items should be handled as little as possible.
Based on the observations of conservators experienced in salvaging and cleaning soot-damaged objects, soot tends to become more difficult to remove with the passage of time. It should be removed as soon as possible following the directions of an experienced conservator. Soot resulting from a fire involving synthetic materials tends to be oilier and more difficult to remove than powdery soot.
Controlling Fire Risk
Most museums provide an abundance of fuel to feed a fire. This is particularly true of many historic house museums of wood frame construction, with period rooms full of combustible objects and interior finishes. Archival storage vaults and facilities equipped with movable (compact) storage systems also typically contain high fuel loads.
Some collections may themselves pose a further risk. In the event of a fire, cellulose nitrate film, natural history collections stored in alcohol, and explosives such as munitions and some mining equipment can be particularly dangerous for fire fighters. Where possible, these objects should be rendered safe, modifications to them documented, and practices established and implemented for their safe handling, storage, and display. For hazardous areas such as chemical supply rooms or areas containing hazardous collections, mount warning signs to alert staff - and the fire service – of any dangers.
Some situations that potentially increase a museum's risk of serious damage cannot be avoided; for example, the combustible construction of a wood-frame historic house museum, or the location of a museum in a remote area where the water supply may not be dependable or where the response time of the local fire service may be much longer than in a larger centre. However, measures can still be taken to reduce the risk and severity of fire by developing and implementing fire prevention and response policies, plans and procedures, by enforcing fire safe practices, and by upgrading the facility.
Table 1 identifies some ways to reduce the risk of fire, or to minimize its impact. Measures will vary from one institution to another due to differing needs, resources, and expertise available. Not all measures may apply to your situation, nor is this list exhaustive.
Some strategies for reducing fire risk and damage.
General (all hazards)
Develop and implement a fire protection program that addresses fire prevention, building upgrades, fire response procedures, fire protection systems and devices, and staff training.
Establish a fire prevention committee consisting of both management and staff. Meet regularly to discuss fire safety issues.
Develop and implement fire safety policies, practices, and procedures to create a safe environment for both people and objects. For example: implement a "no smoking" policy; remove clutter and rubbish; prohibit the use of open flames and temporary wiring; prohibit using heat-generating equipment near combustible material; etc.
Train staff in fire prevention, fire evacuation procedures, and the use of portable fire extinguishers.
Undertake a risk assessment to identify and prioritize fire threats, plus measures to reduce them.
Undertake regular inspections and eliminate any hazards found. Use an inspection checklist to make sure that nothing is overlooked.
Develop a good rapport with your local fire service. Invite all shifts to the museum to familiarize them with its construction, layout, contents, and any hazardous areas such as chemical storage areas, spray paint booths, or areas containing hazardous collections.
Discuss your concerns about water damage and let the fire service know which is more important — the building or its contents. Ask for ways to make your museum safer, and for information on fire prevention. Hold annual fire evacuation drills.
Invite a Crime Prevention Officer — or other law enforcement representative — to visit your museum to advise on ways of making it more secure.
If planning a new facility or renovating an existing one, use non-combustible and fire-resistive materials, divide the building into fire-rated compartments, and install fire protection systems to detect and control fire and smoke. Install or improve fire and smoke barriers where necessary, as well as fire blocks in concealed spaces and vertical and/or horizontal voids to limit the spread of smoke and fire; ensure that any ceiling, wall, and floor penetration are properly stopped; install approved door-holding devices on fire doors normally kept open; and install the automatic shut-down of the ventilation system in the event of a fire. Have the building's electrical service inspected by an electrician every 10 years or after any changes to ensure that it is safe.
Inspect and maintain all heating and protection systems to keep them in good working order.
Install the most effective and suitable fire protection equipment and systems possible based on your needs and budget, and maintain them in good working order.
Undertake measures to protect collections in storage and on display from fire and water damage.
Develop procedures and plans for dealing with emergency events, handling and salvaging damaged collections, and for protecting over-sized or at-risk items in situ.
|Lightning||Install and maintain lightning protection|
|Proximity to exposure fires, i.e.
||Listen to the news. Keep trees, long grass, and brush cleared back if in a high-risk area. Cover collections to protect them from smoke. Shut down ventilation system. Seal around openings. Wet down site and building(s).|
||Have electrical system and work inspected by an electrician.
Ensure all equipment and appliances are listed or approved, in good working order, and are turned off and unplugged when not in use. Dispose of items with frayed cords, or where their safe use is suspect. Do not overload circuits. Ensure that fuses and circuit breakers are used appropriately. Avoid using extension cords and multiple plug adaptors. Add more outlets if necessary. Use only CSA (Canadian Standards Association) or ULC (Underwriters' Laboratories of Canada) rated electrical equipment.
Use of open flames and heat sources (i.e. interpretive fires, portable heaters, etc.)
Hot work (i.e. welding, cutting, burning)
|Keep heat and flames away from combustible materials. Use a fire screen on fireplaces. Keep a fire extinguisher at hand. Maintain a "fire watch" with people who are trained to use extinguishers.
Establish a hot work permit system where relevant. Supervise work and maintain a fire watch during work (and for at least one hour afterwards). Remove combustible material from hot work area. Keep an appropriate portable extinguisher at hand and ensure fire protection systems are operational at the end of the day.
|Flammable liquids in the building||Keep only small quantities inside the building. Implement correct handling, storage, and disposal procedures. Maintain up-to-date Material Safety Data Sheets (MSDSs) and label containers appropriately. Prohibit the storage of these liquids in mechanical or electrical rooms or near electrical boxes.|
|Hazardous collections such as cellulose nitrate film, ammunition, explosives, flammable liquid collections, etc.||Examine collections to identify hazardous items. Deactivate items where possible to make them safe to handle and store or exhibit,; label items accordingly, and keep a record of what was done. Store nitrate film using cold storage, or have it copied by an experienced firm and dispose of originals (i.e. consult the fire department regarding safe disposal), or give originals to an archive experienced in storing them safely.|
|Arson (sometimes used to direct attention away from another crime such as a theft)||Ask a Crime Prevention Officer for advice on ways to make your institution more secure. Keep the building exterior well lit at night; remove any unnecessary materials/items near the building that could be used to fuel a fire; cut back shrubs that could conceal an intruder or arsonist, especially around doors and windows. Ask police to patrol at night. Do security checks on all prospective employees. Hire extra security during controversial exhibits. Develop and maintain good public and community relations.|
The spread of fire and smoke to adjoining areas or throughout the building can be partially controlled by incorporating certain architectural elements and design features. Some examples include the use of non-combustible and fire-resistive construction and finishes; automatic ventilation shut-down in the event of a fire; compartmentalizing or separating spaces such as collections reserves and high-hazard areas into fire-rated areas; installing fire blocks and barriers in attics and in concealed spaces and voids under floor boards, above ceilings, behind walls, etc.; stopping open spaces around current or removed plumbing, duct work, electrical conduits, etc. in walls, floors, and ceilings; fully enclosing stairwells; and installing fire doors. If fire doors are normally kept open, they should be equipped with automatic door-closing devices that close the doors automatically when the fire alarm system activates.
Many museums have worked closely and successfully with their local fire service to improve fire safety at their institutions, and to develop measures for protecting their irreplaceable collections in the event of a fire. In many cases, and providing that the fire is controlled and life safety is not an issue, steps can be taken to protect objects from heat, smoke, soot, and water. Valuable items have been spared from certain loss and damage by evacuating them to a safe area, by covering items with waterproof tarps, by diverting the water resulting from fire fighting, and by using water mist instead of water streams when combating a fire. Take the time to develop a good relationship with your fire service, give them copies of your building plans, and conduct tours of the museum for all members of the service to familiarize them with the building's layout and systems (i.e. the location of stand pipes and sprinkler zone valves), as well as any areas that might be potential fire sources or that could present potential or unexpected hazards during fire fighting. Ensure that they have the access they require to go throughout the building in the event of a fire, have them review your fire response procedures, and involve them in fire prevention and fire response training for staff.
Fire Protection Equipment and Systems
Active fire protection refers to installing equipment, systems, and devices that require power to function such as fire detection, fire alarm, and fire suppression systems. Whether installing a brand new system, or replacing an existing one, use a fire protection specialist who is experienced in designing systems for heritage or clean room facilities and who will work with you to ensure that your fire protection objectives are met. While the cost of professionally designed, installed, maintained, and monitored fire protection may seem large, the cost of not installing them could be even greater.
The fire protection specialist will assess what system to use (to protect life safety only, building and contents, collections, all, etc.); what hazards they are protecting against; the construction, size, and configuration of the structure and the spaces within it; the actual or intended use of the spaces being protected; available water supply and pressure; and much more. For small to mid-size institutions, conventional systems that are simple, reliable, and economical to install and maintain, will suffice. Larger institutions with more complex requirements will require more complex systems. As an example, medium-size institutions may only require a basic control panel that will indicate that a device has activated somewhere, while larger institutions will require highly sophisticated control panels that precisely identify which device has activated, as well as performing other functions.
All systems should be designed and installed according to applicable codes and standards. Use the best quality components you can afford; often the difference in cost between quality is marginal, and the savings not worth the difference in value. Depending on the size and resources of an institution, systems will be monitored by an external monitoring firm, or directly by the local fire department if the service is available in your community. Larger institutions may have in-house staff who monitor their systems, and may also have a backup power supply in the event of power loss. Once installed, systems need to be inspected, tested, and maintained by a competent person and in accordance with applicable codes.
Automatic Fire Detection
While smoke alarm devices may alert people in the area to danger and to prompt the immediate evacuation of the building, they are inadequate for protecting cultural property. That is because most museum buildings are unoccupied for much of the time. Unless someone is present to hear the alarm and call the fire department, a fire may grow and spread rapidly and undetected before someone notices the fire and contacts the fire service.
Fire detection and fire alarm systems can range from basic to complex systems that identify which detection device has been activated, and which perform a number of secondary functions such as shutting down air circulation systems, closing smoke dampers in duct work, releasing door-holding devices on fire doors, notifying a 24–7 monitoring service, and initiating the activation of some type of automatic fire suppression system (consult Vignette 2).
There are two main types of fire detection — smoke detection and heat detection. Because smoke detectors are designed to detect fire in its earliest stages, they are recommended throughout, except in dusty or smoky areas where smoke detectors would be prone to false alarms.
As mentioned above, be sure to consult with a fire protection professional to ensure that each area of the building is protected with the most effective type of detection for that space and to reduce the chance of false alarms. When placing detectors, it is also crucial to take into account air currents created by ventilation systems or open windows, any obstruction, or other factors that may affect the effectiveness of the units.
Smoke detectors are devices that detect visible or invisible particles of combustion.
There are mainly two types: photoelectric and ionization. Photoelectric detectors are most effective for smoldering fires, which produce large smoke particles, while ionization systems provide a quicker response to high-energy flaming fires, which produce large quantities of small smoke particles. Combination ionization–photoelectric detectors, known as "photo–ion smoke detectors," can be installed where protection from both types of fire is desired. Photoelectric detectors have become more popular in recent years not only because they offer substantial faster response in detecting low-energy (smoldering) fires, but also because they may equal or surpass ionization detector response to flaming fires when a fire is not close.
Air-aspirating smoke detectors are available that provide very early detection by means of drawing air into a detection chamber through a small tube, and analyzing the air for smoke. Because of its high sensitivity, air-aspirating detectors are advantageous for protecting items of very high value. And because only the tube opening is visible, they are also suitable where conventional detectors may be visually intrusive, for example among decorative moldings and other building features. However this type of detection is more expensive.
Because both heat detectors and automatic sprinkler systems respond to heat and not to smoke, smoke detection is important in order to minimize smoke and soot damage resulting from slow-growing, smoldering fires (consult Vignette 3).
There are generally two types of heat detectors: fixed-temperature and rate-of-rise. Fixed-temperature heat detectors activate when a room's temperature reaches a predetermine level — usually between 57–75°C, while rate-of-rise detectors activate when the rate of temperature increase exceeds a predetermined value, typically around 7–8°C.
Because heat detectors do not detect fire in its earliest stages, they do not provide the same level of protection as smoke detectors do and should, therefore, only be used in those few areas where smoke detectors would likely cause a false alarm regularly — such as in dusty environments — or in areas where fast flaming fires would be more likely to occur. Heat detectors are best suited to protect dusty or confined spaces such as garages, attics, crawlspaces, and unheated areas where the temperature may drop below smoke detector ratings.
Fire Suppression: General
In the event of a fire, early detection and suppression is essential if damage and loss are to be minimized. In most situations, water is still the most widely used fire extinguishing agent: used in fire hoses, sprinklers, water mist systems, and some portable extinguishers. It is abundant, effective, and inexpensive. Water has the ability to cool and to displace the oxygen supply. Where large quantities of water are required, a dependable water supply and water pressure are needed to support the use of fire hoses and, to a lesser degree, sprinkler systems.
Gaseous fire suppression systems are available for more specialized applications.
Following is a brief description of the more common types of fire-suppression equipment and systems for use in heritage institutions.
Portable Fire Extinguishers
Portable fire extinguishers are generally required by code. In the hands of trained individuals, they can be an effective tool in extinguishing small, contained fires.
It is important to select the correct type of extinguisher for the type of fire. If the wrong type of extinguisher is used, it could be ineffective, or even dangerous, in combating a fire. As an example, a water-based extinguisher used on a live electrical fire could result in a serious electrical shock to the person attempting to extinguish the fire. If used on a flammable liquid or grease fire, the water could cause the fire to spread. The type of extinguisher chosen for a certain area should be based on the expected type of fire for that area.
The four main classes of fires and extinguishers used in museums are:
Class A – common combustibles
Class B – flammable liquids
Class C – energized electrical
Class D – combustible metals such as magnesium and sodium
Many institutions have standardized their extinguishers to facilitate use and training. Class-ABC, multi-purpose extinguishers are now often used throughout a building on the advice of the fire department, thereby eliminating the risk of someone using an inappropriate agent.
Consult your local fire authority or advisor to determine which type of extinguisher is most appropriate for each area of your institution. Portable extinguishers are generally installed near exits. They should be mounted on approved brackets, inspected visually monthly, and maintained annually.
Some institutions prefer not to train their staff in how to use their portable extinguishers in order to discourage their use in the event of a fire. The main argument is that staff should sound the alarm, call the fire department (or equivalent fire service), and evacuate the building, allowing the fire department to extinguish the fire. While life safety always comes first, and no one should ever endanger their own life or the lives of others by extinguishing a potentially hazardous fire themselves, there may be situations where they need to use an extinguisher; for example, if the fire is blocking their exit. In addition, there may be situations where using an extinguisher on a small, contained fire can quickly and safely extinguish the fire before it has a chance to spread.
To operate a portable extinguisher, remember the word PASS. Holding the extinguisher with the nozzle facing away from you:
- P – Pull the pin.
- A – Aim at the base of the fire.
- S – Squeeze the lever slowly and evenly.
- S – Sweep the nozzle from side to side.
Unless staff is trained in the proper and safe use of portable extinguishers, there is the possibility that the units will become little more than expensive doorstops (consult Figure 9), or objects on which to hang coats.
Proper training of staff in emergency response can make a difference, especially in a life-threatening situation.
Automatic Fire Suppression
Automatic sprinkler systems consist of a network of fixed pipes connected to a water source, with sprinklers installed at intervals along the pipes designed to discharge water at a pre-set temperature. According to the Fire Sprinkler Network, automatic fire sprinklers have been in use in the United States since , and even today are widely recognized as the single most effective method for fighting the spread of fires in their early stages — before they can cause severe injury to people and damage to property.
Sprinklers (Figure 10) are ready to respond rapidly anytime of the day or night, and are unaffected by adverse traffic or weather conditions, or by dense smoke and toxic fumes. According to some experts, an automatic sprinkler system is the single most important fire-safety system a cultural property can have. A properly designed, installed, and maintained system can overcome deficiencies in risk management, building construction, and emergency response, and provide enhanced flexibility of building design.
Because most museums contain large quantities of irreplaceable and highly combustible materials and fires can grow and spread rapidly, automatic fire suppression such as sprinkler systems throughout is highly recommended in order to control — and even extinguish — fire in the time that it takes for the fire department to arrive and to set up to extinguishing capacity. Many institutions feel that they are well protected by their proximity to the local fire service and, therefore feel that they do not need automatic fire suppression. However, in addition to the potential delays and problems noted above, there is also the possibility that the fire service may be out on another call. With a sprinkler system, fire protection is in place at all times. Not surprisingly, institutions that have suffered the greatest fire losses were not equipped with sprinklers. Museums protected with sprinklers typically had comparatively minor damage and loss.
Many collection-holding institutions are reluctant to install sprinklers due to the fear of exposing their collections to the potential risk of inadvertent water damage. In fact, accidental discharges and leaks due to manufacturing defects are relatively rare. In addition, damage from sprinklers is generally far less than from high-powered fire hoses used for fire fighting. Water discharge from sprinklers is approximately 100 litres per sprinkler per minute dispersed as a gentle "rain," versus the discharge rate of approximately 500–1,000 litres per hose per minute, discharged under high pressure.
Other institutions argue that installing sprinklers is too expensive. Unfortunately, many museums unprotected by sprinklers have ended up paying twice: once for the costs of recovery and rebuilding following a fire and again for installing a sprinkler after the fact! In most cases, the cost of the sprinkler system was the lesser of the two costs.
Where aesthetics is important, for example in historic house museums, less visually intrusive sidewall or recessed sprinklers can be installed, with covers made to match the surrounding wall or ceiling. However, bear in mind that matching the colour must be done by the manufacturer. It is against code to paint over or otherwise tamper with sprinklers as this could effect their operation.
While total flooding sprinkler systems are available for industrial spaces, they are not generally used in cultural facilities. Typically, only those sprinklers that are directly affected by the fire will activate. Most fires are brought under control using 1–4 sprinklers.
For institutions located in seismic areas, it is important that sprinkler systems be installed using seismic bracing and other features.
In general there are three main types of sprinkler systems: wet pipe; dry pipe; and pre-action systems. Following is a brief description of each of these systems, and some of their advantages and disadvantages.
Wet pipe system
In a wet pipe system, the piped water system is kept under pressure and uses heat-actuated sprinklers. The sprinklers affected by high heat activate individually to suppress the fire. In most situations, a standard wet pipe system is highly recommended because it is reliable, easy to maintain, relatively inexpensive, and is kept fully charged and ready to activate, responding quickly. The main disadvantage with a wet pipe system is that accidental water damage may occur; however, this is very rare and the risk may be reduced. For example, if there is the risk of sprinkler heads being knocked (i.e. by people, cabinets, forklifts, etc.), they can be installed in an upright, sidewall, or recessed position rather than in the standard pendant position, or pendant heads can be fitted with protective cages.
Dry pipe system
In a dry pipe system, the piped system is filled with pressurized air instead of water, which is held behind a valve. When a sprinkler activates, the air is released from the pipe, opening the valve and releasing water into the pipes and out of the sprinkler. Unfortunately, dry-pipe systems are prone to corrosion and scale build-up in the pipes due to condensation and from residual moisture after required testing, making them less reliable than wet pipe systems. As are pre-action systems, they are more complicated, more expensive, more difficult to maintain, and are slower to discharge. Dry pipe systems are mainly used in spaces such as loading bays that are subject to freezing.
In a pre-action system, water is held behind a valve as with a dry pipe system, but requires the activation of a fire detection system to open the valve and release water into the pipes. Once this happens, the system is now ready to function like a wet pipe system.
Many institutions have installed pre-action systems instead of wet pipe systems in order to reduce the risk of inadvertent water damage in collection areas due to accidental discharge, or to leaking pipes or sprinkler heads. However, while this feature is indeed a benefit in areas containing highly valuable water-sensitive collections, pre-action systems are not without their problems and disadvantages, for example:
- This type of system takes longer to reach discharge capacity, allowing the fire to spread during this time and requiring more heads to activate, resulting in more water damage.
- Pre-action systems are more complex than conventional wet pipe systems, with the increased risk of something going wrong. As an example, a problem with the fire detection system could affect the proper operation of the sprinkler system.
- As in the case of dry pipe sprinklers, because the pipes are filled with air, moisture in the pipes could result in corrosion and scale build-up and affect the proper operation of the system.
- Because of their complexity, pre-action systems are more expensive to install and maintain than their wet pipe counterparts.
On/off systems are available in which the activated sprinklers turn off automatically when the room temperature falls below a set point, and will re-activate should the fire re-ignite. However, these systems are complex and expensive. In most urban centres, the fire service will generally arrive before the affected area has even cooled down enough to shut off the system. Therefore, these systems offer few advantages to most heritage institutions.
Regardless of the type of sprinkler system, all systems should be: designed by experienced professionals;, manufactured by a reputable firm using high-quality materials;, installed in conformance with NFPA 13: Standard for the Installation of Sprinkler Systems; and tested and maintained annually by competent personnel to keep them in good working order.
Water mist system
A relatively new water-based fire suppression system has been developed whereby small quantities of water are released under high pressure as a fine mist. This effectively cools and controls a fire using approximately 10% the amount of water discharged by a conventional sprinkler system, resulting in less water damage.
Because water in a fine spray form does not conduct electricity the same way a stream of water does, it can be used on live electrical equipment. Where a clean water discharge is critical, stainless steel piping and distilled water can be employed.
While water mist systems were initially designed mainly for marine applications, they are being seen more and more in museum and archival facilities, and in heritage buildings. These systems are particularly practical for historic buildings undergoing retrofits because smaller diameter and flexible piping can be used in narrow and awkward spaces where the installation of traditional sprinkler systems may be difficult or impossible without disrupting original construction.
Water mist systems can be installed plumbed to a permanent water supply or connected to a series of water tanks stored nearby. This latter scenario might be appropriate in situations where the water supply is not dependable, or for seasonal institutions that are unheated during the winter. Because water is not kept in the pipes, areas of the building subject to freezing can still be protected providing the water tanks themselves are kept from freezing.
While this type of fire suppression system shows great promise for heritage institutions, it is still quite a new technology and, as such, there may be problems finding contractors who are familiar and experienced in installing it. However, this should become less of a problem as these systems become more common.
Automatic gaseous suppression systems
Since the demise of CFC-containing Halon gas for environmental reasons, several so-called "Halon alternatives" have been developed that some museums are installing in collection areas as an alternative to water-based systems. However, for those institutions that currently have Halon systems, there is no true replacement "drop in" system because new piping is generally required.
Unlike sprinkler heads that discharge individually, gaseous fire suppression systems are total flooding systems whereby the agent discharges from all the nozzles within the protected space simultaneously in order to reach the required concentration levels necessary for effective extinguishment.
Gaseous fire suppression systems offer the advantage of no water damage to collections. However, as with other types of suppression systems, there are disadvantages, restrictions, and issues associated with gaseous systems that should be considered when choosing an automatic suppression system. For example:
- These systems are primarily designed for well-sealed spaces such as storage vaults. Their effectiveness will be compromised if the door to the protected area is propped open, if there are any openings through which the gas can escape, or if the ventilation system and smoke dampers have not shut down.
- Some systems require venting to the outside to allow displacement of room air.
- Once the gas has discharged and dissipated, the area is no longer protected until the gas is replaced and the system is recharged. As a result, a sprinkler system backup is highly recommended.
- Gaseous systems are typically more expensive than sprinkler systems.
- Gaseous systems are quite complex, and require everything to function properly in order for the system to operate effectively.
- Design, installation, maintenance, and servicing by competent personnel of systems in institutions located in more remote areas or in smaller centres, may not be practical, economical, or even available.
Following is a brief description of several gaseous agents found in Canadian museums.
Inergen is an inert gas composed of nitrogen (52%), argon (40%), and carbon dioxide (8%). Although this system extinguishes fire by reducing the concentration of oxygen below that which will sustain combustion, the concentration of oxygen remains above the lower limit required for breathing, making it safe for people. Being completely inert and non-residual, it is also safe for collections. Discharge of the agent does not restrict visibility, nor does it result in a large temperature drop as with some other systems.
Inergen discharges under high pressure and requires heavy-duty hardware that will withstand the pressure. Inergen also requires a larger number of storage cylinders of agent than do some other systems to protect the same size area, which could result in space and weight implications.
While the cost of the hardware is generally higher than for some other systems, the agent is less expensive and is easier to replace.
FM 200 is a halocarbon gas that extinguishes fire by means of heat absorption. While there is no risk of oxygen reaching a dangerously low level, there are still some health implications because harmful chemicals are released during discharge.
FM 200 is stored as a liquid and is discharged as a gas. Because it requires a relatively limited volume of stored liquid, it is an option where only limited storage space is available.
Some disadvantages of FM 200 include some global warming potential and the formation of some decomposition products that could affect collections. While the system is typically less expensive to install, the cost of the agent is greater than for inert gas agents.
While NOVEC 1230 total-flooding, fluorinated ketone, clean agent fire suppression has been installed throughout Europe for a number of years, it is relatively new to North America, and especially to Canada. Shipped and stored as a liquid, it vapourizes upon discharge and extinguishes fires by absorbing heat. NOVEC 1230 fluid has the lowest atmospheric lifetime (i.e. 5 days versus 33 years) of current halocarbon fire suppression agents, the greatest margin of safety for use in occupied spaces, and has zero ozone depletion potential.
Fewer tanks of the agent are generally required to protect the same volume of space as some other gaseous systems. However, while less storage space is required, the tanks must be located within 20 to 30 m of the space to be protected. As with most gaseous systems, NOVEC 1230 discharges at a high pressure.
NOVEC 1230 eliminates water or chemical damage to computers, electronics, books, artwork, etc. In demonstrations, items immersed in the agent have been removed dry and undamaged.
The above three gaseous systems are briefly summarized in Table 2.
As with any other fire protection systems, consult a fire protection engineer to determine if a gaseous fire suppression system is appropriate for your institution.
On the night of , the Miner's Museum of Cape Breton (Figure 7) in Glace Bay, Nova Scotia, suffered a catastrophic fire. While the cause of the fire is not known to museum staff, it may have originated from either smoking that took place during an evening concert in the adjoining auditorium, or from vandalism (remains of Molotov cocktails had been found on the premises in the weeks before the fire). The structure was a modern non-combustible and fire-resistive construction, and included an auditorium, and a National Exhibition Centre for displaying travelling exhibits. There was no monitored fire alarm system or automatic suppression system, nor was there a fire door leading to a coal mine shaft located underneath the museum. Former coal miners served as guides, and the mineshaft was popular with visitors.
On the night of the fire, a concert featuring the Men of the Deeps took place in the auditorium. As was the custom at the time, smoking was permitted. Approximately one hour after the end of the concert, a passerby noticed flames shooting from the clerestory windows of the museum's library and called the volunteer fire department. The fire service arrived quickly and additional support was brought in from nearby Sydney. The fire burned for three nights and two days, resulting in the loss of approximately 70–80% of the building and the collections (Figure 8). Because the main priority of the fire service was to prevent the fire spreading to the coal seams in the mineshaft, the remainder of the museum was sacrificed.
If the museum had had a monitored smoke detection system, the fire might have been detected before the onset of flames, while an automatic sprinkler system may have controlled — and possibly extinguished — the fire even before the fire service arrived on the scene, resulting in minor, not serious loss.
With the strong support of the community, the museum has since been rebuilt, and includes a monitored security system, video surveillance system inside and out, exterior security lighting, a monitored fire alarm system, both smoke and heat detection, an automatic wet pipe sprinkler system, and metal fire doors protecting the mine entrance.
One night in , a fire resulting from arson broke out in a main floor room of the Billings Estate National Historic Site — a historic house museum — in Ottawa, Ontario (Figure 13). Although the museum was located in a visually remote site set back from both pedestrian and drive-by traffic in a residential neighbourhood, the fire was quickly detected by the monitored smoke detection system, resulting in a rapid response by the fire department.
In the months preceding the fire, plans had begun to install an automatic sprinkler system. The director of the museum had also met with the fire department to discuss her concerns regarding potential water damage in the event of a fire. This discussion turned out to be fortuitous! Because the fire occurred during non-working hours, life safety was not an issue. As well, because the fire department arrived while the fire was still relatively contained and controllable, the fire fighters were able to enter the structure using carbon dioxide fire extinguishers while the hoses were connected to the standpipe. Once connected, the blaze was fought using water spray rather than streams of water.
Although there was fairly extensive soot damage throughout the museum, as well as some heat and flame damage in the room where the fire originated (Figure 14), there was virtually no water damage to the house or to the collections. The museum has since installed a sprinkler system.
During renovation and construction of new and existing permanent exhibit galleries at the then Saskatchewan Museum of Natural History (now the Royal Saskatchewan Museum), Regina, Saskatchewan, a smoldering fire began when the heat released by the curing of a two-part foam insulation compound became trapped while in contact with modern fire-resistive construction materials, resulting in the development and the spread of heavy smoke. Because the smoke detectors in the project area had been covered to prevent dust contamination during renovations, detection of the fire was delayed until a smoke detector elsewhere in the museum activated. In addition, the fan of the museum's air handling system failed to shut down, allowing smoke to spread rapidly throughout the facility.
Although response time by the fire department was rapid, the accumulation of thick smoke and the lack of a zoned fire alarm system, prevented the fire fighters from locating the source of the fire quickly, resulting in a thick layer of soot deposited throughout the museum, including the permanent galleries and dioramas. Fortunately, most of the museum's collections had been removed and relocated to an off-site storage facility before the renovation work.
Statistics indicate that construction and renovations are extremely high-risk activities for museums. In this case, had the smoke detectors been rendered operational at the end of each working day, and had a fire watch been implemented during the construction work period and for several hours afterwards, the fire may have been detected sooner and extinguished before much damage occurred.
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Canadian Conservation Institute. Fire Protection Issues for Historic Buildings. CCI Notes 2/6. Ottawa: Canadian Conservation Insitute, .
Canadian Conservation Institute. Museum Fires and Losses. CCI Notes 2/7. Ottawa: Canadian Conservation Institute,.
Canadian Conservation Institute. Automatic Sprinkler Systems for Museums. CCI Notes 2/8. Ottawa: Canadian Conservation Institute, .
National Fire Protection Association (NFPA). NFPA 909: Code for the Protection of Cultural Resource Properties - Museums, Libraries, and Places of Worship. Quincy, MA: National Fire Protection Association, Edition.
NFPA 914: Code for the Protection of Historic Structures. Quincy, MA: National Fire Protection Association, Edition.
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