Monday, March 05, 2007

Fire Protection and Resistance in Historic Buildings

CD PROCEEDINGS: INAUGURAL INTERNATIONAL CONFERENCE SOUTHEAST ASIA SINCE 1945 REFLECTIONS & VISIONS, 20-23 JULY 2004, HOTEL EQUATORIAL PENANG, MALAYSIA


Kamarul Syahril Bin Kamal1 and Lilawati Bte Ab Wahab2
12University Technology MARA, Malaysia

ABSTRACT

Over the centuries, fire has continually caused injury, loss of life and destruction of property. Fire can also destroy the national priceless heritage, which is historic buildings. It has been accepted as a fact, that as buildings become older, less fire protection is required. Hence, more people are placed at risk from fire than before. An outbreak of fire in an historic building often has more serious consequences rather than on a modern building. This is caused by the large amount of timber used in the construction and the weakness in fire resistance of the buildings structure and fabric. Many historic buildings in Malaysia are considerable of architectural and historical importance and their destruction by fire is an irreplaceable loss. They should be well kept and protected from the danger of fire at all time. Lessons of major fire in historic building such as Sultan Abdul Samad building in Kuala Lumpur, is that every building should have good fire protection and resistance to prevent from fire outbreak. The protection of historic buildings from fire damage is important. Many of these buildings were built without much thought given to fire protection and resistance. Such things as fire walls and fire stops may not have been incorporated into the structure and many of these buildings utilize timber for much of their framing. When fire occur in these buildings, it can quickly spread and cause major damage in a very short time. Most historic buildings were also built with less or no regard for automatic fire detection or extinguishing systems. Fire resistance for example, is one of the ways to minimize the outbreak of fire from destroying historic buildings. Even though most historic buildings were built with fire resistant materials, by today’s standards, they all fall far below the required performance with regard to Uniform Building By-Laws 1984. Efforts should be made to upgrade fire protection and resistance at historic buildings to make sure that it is safe from the danger of fire with concerned of preserving the building fabric without destroying or changing the features of existing building. This paper will focus on several techniques and methods of fire protection and resistance to prevent fire from threatening and destroying the structure and fabrics of historic buildings, which are rich in architectural and artistic values. It is hoped that this paper could contribute to some changes, as perspective approach leads to suitable techniques and methods of designing and upgrading fire protection and resistance by architects, conservators, planners, builders, contractors and fire authorities to deal with features of construction, internal decoration and furnishing that will not affect the special architectural or historical character of the buildings.

1. INTRODUCTION

Over the centuries, fire has continually caused injury, loss of life and destruction of property. Fire can also destroy the national priceless heritage, which is the historic buildings. Many historic buildings in Malaysia are considerable of architectural and historical importance and their destruction by fire is an irreplaceable loss. They should be well kept and protected from the danger of fire at all time. Lessons of major fires in historic building such as the Sultan Abdul Samad building in Kuala Lumpur, is that every building should have good fire protection and resistance to prevent from fire outbreak. As we all know, most historic buildings are made of various building materials and they are definitely different from today’s construction. At the beginning, the concept of built the buildings is as a shelter from weather. The builders only concern was to build a safe and comfortable building without thinking about fire protection to the buildings. Nowadays, the concept has changed. Fire protection and resistance become one of the priorities and was part of the Building Regulation. Fire protection and resistance has been one of the aspects of a building’s design. But old buildings, which are not, comply with the Building Regulations must therefore upgrade the fire protection and resistance to their buildings to get an approval of Certificate of Fitness from the authority. The protection of historic buildings from fire damage is important. Many of these buildings were built without much thought given to fire protection. Things such as fire walls and fire stops may not have been incorporated into the structure and many of these buildings utilize timber for much of their framing. Thus when a fire occur in a building, it can quickly spread and cause major damage in a very short time. Most historic buildings were also built with less or no regard for automatic fire detection or extinguishing systems. It should be noted, that fire protection and resistance is important in order to minimize the outbreak of fire from destroying historic buildings. Most historic buildings were built with fire resistant materials, which is by today’s standard, fall far below the required performance with regard to Uniform Building By-Laws 1984. Efforts should be made to upgrade the fire protection and resistance at historic buildings to ensure that they are safe from the danger of fire, as to preserve the buildings fabric without destroying or changing the features of the existing building, which is rich in architectural and artistic values.

2. FIRE PROBLEMS TO HISTORIC BUILDINGS

Fire is no respecter of historic buildings, nor does regulations and codes for fire protection respect the cultural and artistic values in a historic building. Normally the fire authorities and conservationists’ aim are to:
1. Protect life from the danger of fire.
2. Prevent from fire outbreak.
3. Minimise the damage caused by fire.

Morally the destruction of any historic building by fire is worse than total loss, for the loss could have been prevented in most cases. It is therefore desirably important to examine first, the cause of fire and then the means of lessening its extent and effect through fire resistance. Basically, the main problems in historic buildings can be summarised as follows:
1. Failure to consult fire brigade officers, failure to appoint local fire prevention officers and failure to organise regular fire drills.
2. Poor standards of management, housekeeping and supervision.
3. The danger from smoking and cooking operations.
4. Faulty electrical installations.
5. Flammable decorative materials and furnishings.
6. Lack of compartmentation, no internal subdivisions, stairways not enclosed, wall linings not fire stopped and etc.
7. Deficient fire resistance; inadequate walls and floors, doors not fire resisting and etc.
8. Inadequate means of escape; doors, passages, staircases have excessive travel distance; no alternative escape routes and etc.
9. The danger of arson.
10. Lack of master keys and mastered locks.
11. The danger from workmen, especially when using flame for repair work.
12. Possible danger from lightning.

One of the most important lessons of major fires, such as Sultan Abdul Samad Building is that every historic building should have a good fire protection and resistance where the condition of the structure which include the characteristics of flammability, disposition of furnishings and electric wiring should be considered. Prevention of fire to historic buildings depend on the awareness of the owners, professionals, the public and workmen. (Fielden, 1996:233). Actions should include:
1. Appointing a fire prevention officer, organising fire drills and rescue practice.
2. Ensuring adequate water for fire fighting and good access for fire engines.
3. Identifying important risk and danger of spreading fire, and eliminating unnecessary hazards.
4. Consulting a competent fire engineer/maintenance officer.
5. Ensuring what can be achieved by compartmentation.
6. Upgrading fire resistance on walls, floors, roofs and doors.
7. Considering the early detection system and the merit of sprinkler system.
8. Making checklists for monthly, weekly and daily routine inspections.

3. RISKS AND EFFECTS OF FIRE IN HISTORIC BUILDINGS

It has been accepted as a fact, that as buildings become older, the less fire protection is required. Hence, more people are placed at risk from fire than before. Fire can also destroy the priceless heritage of historic buildings. There are two primary factors that must be considered as follows:
1. The protection of the persons living, working or visiting the premises.
2. The protection of the building fabrics and its valuable contents.

Conserving or adapting historic buildings to new uses is more difficult than building a new one. In adapting historic buildings to meet new uses and modern standards, there need to be some physical changes to the existing one. It may involve major or minor upgrading to produce better quality building. One of the aspects that should be considered as significant in ensuring that the building complies with current regulation where applicable, and this invariably requires the physical upgrading of certain elements particularly with regard to fire protection. The outbreak of fire in historic buildings often has more serious consequences than on modern buildings. This is caused by the large amount of timber and brick used in the construction and the building structure that results on the weakness of fabric in fire resistance. The relative priorities for life safety and historic building protection will be viewed differently by those involved in the specification and definition of requirements. The fire authorities or the local fire brigade will be primarily concerned with ensuring the optimum standards are achieved for the provision of means of escape and for the inclusion of means of fire fighting. Meanwhile conservationist, is primarily concerned with preserving the buildings fabric without the intrusive effects and loss of fabric which are inevitable consequences of most standard fire resistant measures. The owner of historic buildings is therefore left in somewhat of a dilemma like:
1. What are the legal requirements?
2. What life safety standards should be considered for the current and future usage and occupancy?
3. What provisions should be made to protect the building and its contents against the ravage of fire?
4. What are the fire protection equipment that need to be installed in the building?
5. What are the buildings elements that need to be upgraded in terms of fire resistance?
6. What is the risk of taking all of these actions?

These questions cannot be easily answered. The upgrading of fire safety design standards advocated by the current Uniform Building By-Laws 1984, primarily apply to building work only. However, they can affect existing historic buildings where materials alterations proposed will effectively upgrade the existing provisions concerned by the regulations. They also apply where there is a material change of use including conversions to form museums, a public building or a dwelling.

4. REGULATIONS RELATING TO FIRE SAFETY

Damage or loss caused by fire is a constant threat to historic buildings. Fire safety laws have a history almost as long as the building; indeed, some traditional design features and materials are less inflammable than those being used today. It is generally considered by fire safety engineers that well maintained buildings present lower fire risks and that good housekeeping is an important part of fire safety management. (Edward, 1994:202). Basically there are two main approaches to be achieved by fire safety:
1. Fire prevention designed to reduce the chance of a fire starting.
2. Fire protection designed to mitigate the effects of a fire should it nevertheless occur.

By law, the owner of a building open to the public is responsible for providing adequate fire protection for the occupants. The Uniform Building By-Laws 1984 only deal with fire protection of the structure in all new buildings and, where alterations are being made in existing buildings. Meanwhile the Fire Services Act 1988 (Act 341) sets standards for fire protection, which apply to certain categories of existing buildings. The legislation is not retrospective and can only be enforced when the use of the building is to be changed or when the structure is to be modified. Basically, there is no application of the act for historic building and if there is one, it should strike a balance between the two ideas of protection and preservation. The measures should represent the minimum necessary to ensure protection of the building’s occupants while avoiding, where possible, alterations to the architectural character of the building. This may include some compromising between active and passive fire protection measures. (Davey, Heath, Hodges, Ketchin & Milne, 1988:17). Fire regulations are framed chiefly with the design of new buildings in mind, rather than the improvement of existing buildings, and their primary concern is, quite rightly, the safeguarding of life rather than the safeguarding the contents of the building. Historic buildings require wider priorities; it is suggested that the objective should be broken down into three parts:
1. To prevent the outbreak of fire.
2. To minimise the effects of fire by preventing it from spreading.
3. To fight fire efficiently with minimum damage done to the contents of the building.

To meet the regulations, the most typical actions that can be done are:
1. Planning alternative protected escape routes, uses of paint or fire retardant to combustible materials and provision of hatches, crawl ways and internal ladders.
2. Forming enclosed staircases, glazed screens and fire doors on magnetic latches and hardwood treads on stairs.
3. Upgrading fire resistance of walls, floors, roofs and doors.
4. Provision of alarms, detectors, emergency lightning and fire fighting equipment such as extinguishers, hose reel, hydrants and sprinklers.
5. Compartmentation with thickening of floor boards or other treatment above the floor joists, fire stopping of cavities and ceiling voids and sealing off ventilation grilles. (Fielden, 1996:238).

5. DESIGNING FIRE PROTECTION FOR HISTORIC BUILDINGS

There is no doubt that fire protection is important to all buildings especially to historic buildings. When designing and installing any fire protection system, careful planning and equipment placement must be utilised to minimise the visual and structural impact of the system to the building. The fire protection specialist is facing with the difficult task of balancing the need for proper fire protection and restoration of the historic fabric of the building. It is not hard to imagine a system where the desire to hide the fire protection systems components results in a system which is minimally effective due to poor placement of these devices. In 1997, the National Fire Protection Association (NFPA) has issued a ‘Standard for the Protection of Cultural Resources’ including museums, libraries, places of worship and historic properties. The document’s concern is about the historic structures of the buildings and it also provides some guidance regarding fixed fire protection systems at these buildings. Basically, there is two type of fire protection that can be used in historic buildings known as active and passive fire protection. Both types have their advantages and disadvantages and both are of value in the overall fire safety design.

5.1. ACTIVE FIRE PROTECTION

The strategy for protection of a historic building and its contents depends on preventing the outbreaks of fires, particularly fire caused by human negligence. From large historic buildings such as high court, museum, railway station, government office and administration building to a small historic buildings such as villa, terrace, flats and etc., (Fielden, 1996:240). There are various types of active fire protection that can be installed such as explained below:

5.1.1. FIREFIGHTING

The oldest, and in many historic buildings, the only, active measure employed is fire fighting. This includes action by the occupants, using first aid appliances such as buckets of sand and hand extinguishers, and action by the fire brigade. Regular maintenance of first aid appliances need to make sure that they are always accessible and in the right place. An extinguisher should always be at the strategic fire point. Meanwhile, facilities provided for the fire brigade’s use include water supplies, wet and dry risers, fire fighting staircase and lift, and controls to override the building system controls. All need to be maintained to the standard required by the fire brigade. In normal condition the fire fighting lifts can be used for passengers but must be kept clear of goods at all time.

5.1.2. DETECTION AND ALARM

A full system of detectors and fire warning alarms are used to raise alarm and alert the occupants. They can also locate the fire and linked directly to the fire brigade at the cost of an annual rental. The placing of detectors in historic buildings demand great care especially in large volumes where height reduces the sensitivity of the detectors. In historic buildings, these problems are frequently met, which limits the performance of detectors because it was designed for typical modern buildings which have small rooms and low ceilings. The number of false alarms can be reduced by having detectors close spaced arranged in an intelligent self monitoring system linked to a microprocessor to check and reset system able to identify cable damage or the failure of a detector. Arrangements should also be made for a responsible official to be available by day and night in case of fire. An internal telephone or radiotelephone system is invaluable for this. Closed circuit infrared television system, which can see in the dark, may become more common and be linked with special security system by direct line to the police station.

5.1.3. AUTOMATIC EXTINCTION

Automatic devices such as drenchers and sprinklers can be useful for historic buildings. The system in its simplest form uses a head incorporating a detector, which releases the water when heated by a plume of gases rising from a fire below. When an alarm is automatically sounded, the sprinkler system is designed to control or extinguish fires while they are small. Although it is the simplest form, but it is wise to remember that sprinklers may cause damage to the contents of the building. So, their use may be ruled out if the contents are historically valuable. In some cases, after the fire has been put out, it was found that the fireman’s hose caused more damage than the fire itself.

5.1.4. SMOKE CONTROL

The term smoke control is used to describe the control of the movement of both smoke and toxic gases. Basically, automatic smoke control system can only be used to historic buildings with close air conditioning systems where smoke dampers can keep escape routes clear of smoke and smoke extractor can vent smoke out from the historic buildings. This is so that the fire brigade can enter the building to tackle the fire and also in buildings where it may be necessary to travel a relatively long distance to reach exit, for example, in covered museums, it is a normal practice to provide smoke control for the exhibition walkways. Meanwhile pressurization system is also important to multi storey historic buildings where they are designed to stop smoke from entering protected routes, such as stairways, by promoting a favourable airflow across the entrance door. In order for pressurization to be effective in an emergency, only a limited number of doors should be open at any one time on each protected route.

5.1.5. DOOR CONTROL

Certain doors and shutters are designed as part of the fire protection system to restrict the passage of fire and smoke. When doors need to be kept open for a long period of time during the normal operation of the building, they can be fitted with automatic closing devices operated by fire detectors, but it is obvious that the area must be kept clear so that the door can close freely when necessary. Locks for the doors should also be standardised so that the fire brigade can open all relevant doors with one master key. At night, all internal doors should be left closed but unlocked, if security permits. As a conclusion, in choosing a system, one must consider capital costs, maintenance and running costs in comparison with the cost of equivalent protection from manpower. Generally, detection systems are the best solution because it is much cheaper and constantly alert.

5.2. PASSIVE FIRE PROTECTION

Current perspective fire safety standards rely very heavily on passive fire protection, usually involving the enclosure of staircase and corridors leading to final escape points and the provision of fire doors across passageways. In addition to the intrusion that the additional doors and partitions can cause in an historic interior, upgrading the original historic features such as walls, floors, roofs and doors to standards of fire resistance intended for more modern buildings is less than ideal. (Edward, 1994:206). There are various types of passive fire protection that can be designed such as follow:

5.2.1. MEANS OF ESCAPE

Escape routes are designed on the principle that a person confronted by a fire should be able to turn away and proceed by their efforts to an exit leading either directly or via a protected route to a place of safety, usually the open air at ground level. Escape routes should be protected by lobbies and free of obstructions and combustible material. Glazing in doors and screens must be fire resistant, but even so they present a hazard from radiation transmitting intolerable heat, and thus preventing escape on the other side of the fire barrier. Additional means of escape, such as external stairs, can disfigure historic buildings and may prevent its beneficial use. Means of escape cannot be dealt with a series of hard and fast rules, but guidance can be obtained from regulations relating to the number, position and width of exists according to the maximum number of people likely to be in the building at any one time. Sometimes, the number of person who may be present in historic buildings will be limited by the available means of escape. Signs indicating escape routes can also effect the architectural character of historic buildings, as such direction signs must be plainly visible. The construction of walls, floors and ceilings of escape routes must be incombustible. To prevent the spread of smoke and fire into corridors and stairwells, self-closing fire stop doors must be provided and if there are security problems, suitable locks can be installed.

5.2.2. COMPARTMENTATION

Compartmentation in historic buildings is designed to restrict fire and smoke from spreading by containing the fire within a certain area bounded by fire resistant walls, floors and ceilings for a minimum period of thirty minutes. The major points of weakness in the compartment are service ducts, other voids and doors where original doors are rarely able to satisfy the half hour requirement. An important point to note is that while fire doors are effective barriers to flame, they are normally poorly insulated. Meanwhile if fire is able to enter service duct or other void, then the compartmentation may be breached. To guard against this, either the duct must be enclosed in fire resisting construction or there must be a fire resistant barrier wherever a compartment wall or floor is penetrated. In some cases, it may be possible to upgrade their resistance using lining and seals with limited effect on their character and interest, but this may not be acceptable where particularly fine work is concerned. In other cases, there may not be any alternative to completely replacing it, if a passive approach to fire protection is employed. (Forrest, 1996:2). For a compartmentation, to be effective, it must have a complete seal. It is preferable for each compartment to have at least two external doors for fire fighting. Roof compartments can be devised with smoke vents operating by fusible links. Passive measures of fire protection, which do not rely on mechanical devices or human intervention, should be given a high priority in historic buildings as they are always on duty.

5.2.3. STRUCTURAL FIRE PROTECTION

Structural fire protection is the term used to describe the detailing and cladding of elements of structure in historic buildings, which may be made of one or more materials like timber, bricks, masonry, steel and etc., so that they can perform satisfactorily during a fire. Depending on the materials, they may expand, shrink, spall, change their nature, or burn, and they all lose strength which may or may not be regained on cooling. The detailing of joints and fixings is an important feature in which, if neglected, can cause premature failure. The choice of structural material and the cladding, if any will depend on many things, including the environment like wet, dry, corrosive, etc. and also the like hood of mechanical damage and the ease or otherwise maintenance. Although timber burns, the charred layers on the exposed surfaces act as insulation to the unburnt portion beneath, and timber structural elements are designed with an extra layer which can be sacrificed if exposed to fire. Fire retardant treatments are designed to reduce the risk of ignition and flame spread on timber. Unprotected steel on the other hand can only be used successfully in doors, shutters and non load bearing partitions. There are many such materials like wet, dry, spray and board applications that can be used to protect steel elements and the most suitable for historic buildings is the use of intumescent paint where it can expand when heated to form an insulating crust. For brick and masonry, fire resistant can be achieved by increasing the thickness of the plaster to provide the expandable portion.

5.2.4. SURFACE FINISHES OF MATERIALS

In historic buildings, surface finishes should be selected to reduce the chance of ignition and spread of flame. They must be of a high standard, or non combustible, particularly in circulation areas. Many combustible finishes can produce improved performance if they have a fire retardant treatment, but these treatments may be affected adversely by conditions in use and the manufacturer’s instruction. Surfaces which are damaged or where layers are beginning to peel off, may ignite easily and burn rapidly. Fire retardant treatments are often used for curtains, carpets and other fabrics and there may be special laundering or dry cleaning requirements if the treatment is to be preserved. Unfortunately, fire retardant treatments tend to increase the production of smoke. If this is not acceptable, a non combustible material may be the only choice.

6. UPGRADING FIRE RESISTANCE IN HISTORIC BUILDINGS

Fire resistance according to The Aqua Group (1984:181), can be defined as “…the ability of an element of building construction to satisfy for a stated period of time some or all of the criteria specified in B.S. 476: Part 8: 1972 namely resistance to collapse, resistance to flame penetration and resistance to excessive temperature rise on the unexposed face”. The principles of fire resistance related to test methods and criteria for the fire resistance of elements of building construction lays down three specific criteria against which the fire resistance of any element can be measured. (Highfield, 1987:27). They are as follow:
1. Stability: resistance to collapse or excessive deflection.
2. Integrity: resistance to penetration of flames and hot gases.
3. Insulation: resistance to excessive temperature rise on unexposed face.

Thus, the criteria attempt to relate the ability of a structural component to:
1. Endure fire without collapse.
2. Prevent the penetration of flame due to loss of integrity.
3. Resist the spread of fire by conduction through the component or by radiation from the face of the component not exposed to the fire.

The factors that determine the level of fire resistance of structural components are:
1. Type of building.
2. Height of the building.
3. Floor area of the storey or compartment.
4. Cubic capacity of the building or compartment.
5. Location of the component.

Fire resistance is important to prevent fire from threatening or destroying the structure and the contents of historic buildings, which are rich in artistic values. The technique and method of upgrading fire resistance in historic buildings is different from new building because of its speciality. Most of them are listed buildings and are under control by the government. Basically, in upgrading fire resistance in historic buildings, the fire authority will state its requirements in the draft schedules and it is at this point that the owner, conservator, architect and fire consultant if appropriate must decide if such requirements are reasonable or unduly onerous without affecting the special architectural and historical character of the buildings. A large number of the steps to be taken will deal with features of construction, internal planning, and in some cases furnishings. The fire consultant can give helpful guidance and specifications for methods of upgrading fire resistance and supply a number of standard forms as according to the conservators need. (Taylor & Cooke, 1978:6). The following are only broad guidelines, indicating some of the requirements for upgrading some of the elements i.e. walls, floors, roofs and doors in historic buildings. In practice, it is suggested that an architect should always be involved, working closely with the conservators, surveyors, builders, engineers, and fire authorities in designing and upgrading fire resistance. There are four major building elements where fire resistance can be upgraded which are walls, floors, roofs and doors as follow:

6.1. WALLS

In majority of historic buildings, the existing walls are normally brickwork or masonry, both of which have excellent fire resistance, and are therefore, unlikely to be needing an upgrading. For example, an unplastered 100mm thick brick wall will give a fire resistance of two hours, which is more than adequate in virtually all circumstances. Masonry walls, whatever their thickness are, have an inherent fire resistance considerably in excess of half hour or one hour. Structural components within a wall, such as lintels, require an equal fire resistance. However, the possible effect of fire on the whole structure must always be considered. For example, structural components supporting a wall such as beams need to match the degree of fire resistance rating of the wall. (BRE, 1990:67). Unplastered block walls 100mm thick will give a fire resistance of one hour to two hours respectively and are therefore, like brickwork and masonry, unlike to need upgrading for fire protection purposes. Fire resistance of separating and compartment walls are critical to the safety of life in fire situation and limitation of damage in the event of fire to historic buildings. Soundly constructed masonry walls are usually able to provide fire resistance for periods longer than required by the building regulations. This inherent resistance to fire is however easily compromised if any unsealed holes or gaps are left through a wall. Walls generally rely for their stability upon other parts of the structure, such as timber floors or roofs, which are not so resistant to fire. Meanwhile, timber structure and load bearing partitions will need to have fire resistance for a period of half to one and half hours depending on the size of building and locations of partitions. Where partitions support a structural element with a designated fire resistance, then the partition is required to meet at least the same criterion. Adding plasterboard or additional thickness of wet plaster to existing construction most easily increases fire resistance. One of the simplest way of upgrading such partition is to nail an additional layer of 9.5mm plasterboard to each side, which will give a rating of one hour. If greater period of fire resistance is required, a wet plaster finish may be added, or thicker plasterboard be used. Basically, dry linings are suitable and popular alternative to wet plaster as means of upgrading wall surfaces in historic buildings. Providing a dry lining wall finish involves the fixing of gypsum plasterboard to the existing wall surface by one of a number of different techniques. (Highfield, 1987:42).

6.2. FLOORS

In the majority of historic buildings, the undersides of floors did not receive a ceiling finish and so they merely comprise floor boarding on timber joists left exposed on the underside. Such floors come with no regulations and therefore they require extensive upgrading. In addition, many such floors have plain edge boarding which is often found to have distorted over the years, leaving gaps, which, in the absence of a ceiling beneath, render the floor to almost totally ineffective as a fire barrier. In most cases, the fire resistance of the existing timber floors will need to be upgraded to half an hour or one hour, depending on the purpose group and size of the building. It is clear that the floors requiring upgrading will already have some form of ceiling finish like wood lath and plaster. (Highfield, 1987:27). Provided that such a floor has joists not less than 38mm wide and a ceiling of timber lath and plaster not less than 15mm thick. The existing ceiling will, therefore, already provide some degree of fire resistance and generally the upgrading treatment will not need to be as extensive as with floors comprising exposed joists. Normally, the fire authority will require floors to have, or be upgraded to achieve at least thirty minute fire resistance. (Taylor & Cooke, 1978:11).

6.3. ROOFS

Roofs perform a number of functions. In relation to their fire performance, they can perform two functions, to contain a fire or prevent its penetration from an external source and to ensure that the external coverings does not spread fire rapidly so that an adjoining roof might be in danger. (Longdon, 1972:96). In historic buildings, fire separation of the roof space between buildings is often incomplete, perforated or inadequately fire stopped at perimeters. If structural timbers run through firewall consider whether collapse through fire on one side would affect the integrity of the roof on the other side. Meanwhile, it is common to find flat roof joists resting on separating or compartment walls with spaces between each joist. Alternatively, if beam filling is present then in many cases smaller gaps around joists and the underside of the roof deck may be found. If joists bear on the full width of a separating walls or if joists from two dwellings coincide on a wall this can constitute an unacceptable perforation. Subdivision of the ceiling void with cavity barriers is not needed in roof areas between fire division walls. Building regulations normally require roofs to resist penetration of fire from the outside, prevent a fire spreading from one roof to another, and in the event of premature collapse, not to compromise the integrity of any compartment or separating wall, and during fire, not to destroy the integrity of any fire division wall with a prescribed fire resistance typically of one hour. (BRE, 1990:121). The fire resistance of roofs at historic buildings can be improved in several ways. All pitched roofs should have plasterboard or insulation board attached as a fire resistance. The board is fixed and made as airtight as possible by sealing all joints between it and the adjacent surfaces with good quality plaster. The sealing of these insulation boards lining, and the rendering at the edges of the roof, must be maintained in good conditions. Meanwhile to ensure that the roof supports will hold for the minimum amount of time in the event of fire, all timbers should be treated with fire resistance paint or solution in accordance with the manufacturer’s instructions. (Cunnington, 1984:240).

6.4. DOORS

Door assemblies at historic buildings are one of the most important elements of building construction affecting safety of life. Doors with their frames and furniture must have adequate fire resistance and smoke control properties, but this will be useless if they are left open and remain open in the event of fire. It is likely that when historic buildings has been improved or has undergone a change of use, some of the existing external and internal doors will need either to be replaced or upgraded to comply with the requirements of the building regulations. Typical locations where fire doors are required include:
1. Doors separating maisonettes from spaces in common use.
2. Doors penetrating protecting structures i.e. fire resisting enclosures to corridors and stairwell.
3. Doors penetrating compartment walls i.e. fire resisting walls used to subdivide a building into compartments in order to restrict fire spread.

Fire doors will usually need to have a fire resistance of thirty minutes or sixty minutes, and most types of existing doors construction at historic buildings are capable of being upgraded to half an hour with relative ease. Fire test on timber doors suggested that the minimum thickness of solid timber panelling needed to survive a thirty minute test was in the range 20mm to 25mm. Most panelling is thinner and therefore needs reinforcement. (Taylor & Cooke: 1978:7). However, upgrading an existing door to one hour standard is more difficult, and often produces a rather cumbersome result because of weight and thickness limitations. When one-hour fire doors are required, therefore, it is usually preferable to replace the existing doors rather than to attempt to upgrade them. But for doors that have an architectural or historical interest, this method is not appropriate because the door have to be retained at all cost. Therefore, the technique used to upgrade fire resistance of existing doors, wherever they are flush or panelled, are relatively simple and inexpensive. (Highfield, 1987:40). Some type’s of old panelled doors and linings can be made fire resistance without serious damage to their appearance.

7. CONCLUSION

It is hoped that this paper could contribute to some changes as perspective approach leads to suitable techniques and methods of designing and upgrading fire protection and resistance by architects, conservators, surveyors, builders, engineers, locals and fire authorities to deal with features of construction, internal decoration and furnishing that will not affect the special architectural or historical character of the buildings. No building is free from the threat of fire whether it is old or new. A designer however, can ensure that only limited damage will result if fire breaks out by upgrading fire protection and resistance. If a fire grows to a sufficient size within a compartment in historic buildings, then it may breach the bounding walls, floor and roofs and spread to other parts of the building through doors. In order to prevent this from occurring, or to delay its occurrence sufficiently to allow occupants to escape from other parts of the building, bounding elements are designed to have a given level of fire resistance in building elements such as walls, floors, roofs and doors. Fire protection and resistance construction may be described as construction that continues to fulfil its function during the course of a fire, and where walls, floors, roofs and doors are involved in preventing the transmission of fire beyond the boundaries. It is however, frequently necessary to resort to largely non-combustible construction in order to achieve substantial fire endurance i.e. a long fire resistance time period. The fire resistance of building elements is universally defined in terms of the length of time it will meet certain requirements when exposed in a test furnace. For historic buildings, the fire resistance requirements are in turn related to the fire load within it and therefore a bit high. Fire resistance also relates to the ability of the elements to retain its integrity and load bearing capacity, and to provide sufficient insulation. Some of the existing building elements at historic buildings has already have the fire resistance ability such as brick walls that have half to one hour fire resistance and solid timber panel door that have at least half hour of fire resistance. But some of the element didn’t have the element of fire resistance as required by Uniform Building By-Laws 1984 and Fire Services Act 1988 (Act 341) and therefore need to be upgraded. In general, real fires do not follow the standard time/temperature requirement, and simple perspective requirements based upon a minimum time to failure in the furnace test. Nowadays, there are various techniques and methods of upgrading fire protection and resistance in historic buildings. We can conclude that fire protection and resistance is very important to historic buildings, but unfortunately most historic buildings has never been upgraded. Therefore, it is suggest that the buildings should have been upgraded with fire protection and resistance by using one of the following methods as described earlier. The selection of these techniques and methods is agreed to be the best method of upgrading the fire protection and resistance at historic buildings. Although some of it will affect the appearance of the building’s elements, but it can be ensured that less damage is done to the structure.

8. RECOMMENDATIONS

Owners of historic buildings are recommended to seek specialist’s advice before undertaking any work on upgrading the fire protection and resistance at their building. Furthermore, architects, conservators, surveyors, builders, engineers, local authorities, fire authority and other interested responsible bodies must be consulted before any work is carried out. Because of architectural and historical considerations, work to upgrade the fire protection and resistance at historic buildings needs to be carried out with sensitivity so as not to damage the building’s historic interest. There are often alternative ways of improving the fire protection and resistance where it is necessary to do so without making features and structural changes to the building or by keeping changes to an absolute minimum as described in previous chapter. In some small historic buildings for example, which contains a staircase within one single space, with all rooms opening directly off it, further compartmentalisations may be unnecessary. By upgrading the fire resistance at walls and doors to provide half hour fire protection can be avoided by introducing an air pressurisation system. In the event of fire occurring in one of the rooms, the system is activated, rapidly pressurising the escape route and forcing smoke to leave the building through vents introduced in the rooms. However the system has limited application as it can only be used where the staircase is self contained, and due to the problems associated with accommodating the large amount of plant required. It is recommended that historic buildings should install automatic fire detection in areas presenting a high fire risk where by doing so, it could reduce the need for fire resisting construction. Such an approach must be given with the most careful thought. It can only be valid where adequate warning can be expected from detection and alarm systems, and where it is known that the response to an alarm will be the complete evacuation of the building. Special provision may be necessary where there are infant, senile or restrained occupants in the historic buildings. It is also recommended that the owner of historic buildings to check the fire risk assessment that can help in deciding what might need to be done to the historic buildings. Basically, by upgrading the fire resistance at building elements such as walls, floors, roofs and doors, it can reduce the danger of fire spread through these elements. Meanwhile, in terms of fire resistance and life safety, the fire resistance requirements so far discussed have all been related to the duration of the fire. Evacuation of the building would then be the only feature to be considered. Suitable fire resistance recommendations might be that all building elements should comply with structural requirements for one hour and the temperature requirements for thirty minutes. It is hoped that the next decade will be a period of major changes as perspective approach lead to more performance or ‘engineered’ means of upgrading fire protection and resistance in historic buildings. Uniform Building By-Laws 1984 and Fire Services Act 1988 (Act 341) therefore need to be revised.

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