Engineering Design Project for Building Regulations in the United Kingdom - Term Paper Example

Engineering Design Project Introduction B1 is the functional requirement of building regulations in the United Kingdom which aims at ensuring that buildings are well designed and constructed so as to adequate provision for an early warning of a fire outbreak. To do this, a reasonable standard means of escape for the occupants of a building in the event of a fire outbreak should be considered. B1 can be met where there are adequate means of giving early warning of a fire disaster for residents of a certain building; there are routes of a reasonable number as well as capacity, which are easily accessible to make it possible for residents of a building on fire to escape, and the routes are protected sufficiently from fire effects. This report is subdivided into 3 sections in which the B1 functional requirement is critically analyzed and discussed. Section 1: Fire Alarms and Detection Systems In this section, provisions are made for planning to be made in every building so as to give untimely warnings in case of a fire outbreak. These provisions are concerned with actions required to guarantee rational facilities for means of get away in the event of a fire outbreak. They are prepared based on the basis that, the inhabitants of a building should in a position to escape safely, in the case of an emergency, exclusive of any form of external help. Fire detection systems refer to whichever type of automatic sensor set-up, as well as, allied control and indicating tools. The sensors may well be sensitive to high temperatures, smoke, radiation or burning products. Control and indicating equipment are responsible for operating a fire alarm system as well as performing other signaling or control functions. Any fire alarm system that is electrically operated should conform to BS 5839-1:2002 policy which explains the fire detection and alarm systems of buildings requirements, the policy of practice for system design mechanism and maintenance’ (Approved Document B - Fire Safety, 2004). Installation of Fire alarm and detection systems in flats Installation of the automatic detectors along with smoke alarm systems increases safety levels as they automatically give an early warning of a fire outbreak. All flats ought to be equipped with fire detection as well as alarm system so as to comply with the relevant BS 5839-6:2004 recommendations (Approved Document B - Fire Safety, 2004). Smoke and heat alarms should be operated from the mains so as to comply with BS 5446-1:2000 and BS 5446-2:2003 respectively. They must also have a stand by source of power such as a capacitor or battery. The type of detector ought to be chosen while considering the type of fire that is expected to start as different types of detectors respond differently to the different types of fires. Smoke alarms are supposed to be installed in dwelling places with circulation spaces in order to ensure that are warned about any fire (Geoff, 2009). In flats with sheltered housing schemes, the detection equipments should be connected to a central monitoring point to ensure that the personnel in charge can identify flat concerned in the event of a fire outbreak. Positioning of smoke detectors and fire alarms BS 5839-6 gives detailed guidance on how fire detection plus alarm systems should be installed. Smoke alarms must be positioned in circulation spaces as well as places where fires are most likely to break out such as kitchens. At least one smoke alarm and detector should be installed on each floor of a flat. In a situation where more than one alarm system is set up; they must all be linked together so that all alarm signals are operated by the detection of smoke in one detector. The smoke detectors should be installed in such a way that they can be reached with ease when carrying out routine maintenance practices such as cleaning and testing. Smoke detectors should not be fitted in areas with high temperatures such as boilers, bathroom showers or areas that get very cold as this will result in false alarms. According to BS 5839-1 and BS 5839-6, occupiers are recommended to receive instructions from manufacturers regarding the maintenance and operation of the fire alarm systems (Approved Document B - Fire Safety, 2004). Smoke alarm systems power supply Smoke alarm systems should have their power supply tapped from the major supply. The major power supply to the smoke alarm system should be made up of a single and self-sufficient circuit on the major distribution board. This ensures that the circuit will be rarely disconnected for a prolonged period. Power to the smoke detectors should be isolated without isolating the power to the lighting system. Any cable that is appropriate for domestic wiring can be used in the power supply and inter-connection of smoke alarm systems. However, the conductors used for connecting the alarm systems should be easily distinguishable from the conductors supplying the main power. This can be done by use of color coding (BSI, 1998). BS 5839 describes alternative options that exist in smoke alarm systems power supply in part 1 and part 6.For example, the mains’ supply may be decreased to low voltages in a control unit with a stand-by battery prior to being distributed to the alarms at that voltage. Fire alarm systems are categorized into different categories depending on their application and the type of building. Those categorized to protect life are categorized as L, P for those designed to protect buildings and M for manual systems (Fire Alarm System Categories, 2009). Designing and installing a fire alarm and detector systems. Fire detector and alarm systems should be should be designed, installed, and maintained properly. After installing the fire alarm system, it is essential for the setting up and commissioning certificate to be issued. The certification provides the highest possible assurances and offers a high level of quality, safety and reliability. SECTION 2: Building occupancy and purpose groups Fire alarm and detector systems in buildings that are not flats In order to decide on the most appropriate kind of fire alarm and detection system to be set up in a building, the kind of residence as well as escape strategy must be first determined. For example, residents who sleep in a building are more prone to a fire threat unlike in premise where the residents are usually alert. Operating a manual fire detector gives an immediate alert from all the alarm sounders. It should be used in a building where the mode of escape takes place on the basis of synchronized evacuation. Likewise, a staged alarm system is suitable where the mode of escape happens on the basis of phased evacuation. A voice alarm system may be installed in buildings where people are not familiar with the building’s fire warning arrangements. They could be part of a public address system and should be capable of giving a clear signal as well as verbal instructions in case of a fire outbreak. The voice alarm signal should be different from other signals. In a building with large numbers of members of the public present, for example places of assembly and large shops, fully trained individuals should be used to carry out pre-planned procedures of evacuation as alarms would be undesirable. An appropriate method of warning must be installed in buildings where people with impaired hearing are expected to be found. This may be done by making use of vibrating pagers. Purpose groups Provisions in this section are linked to the use of the building. The purpose groups present diverse levels of exposure. They are divided into various categories according to the use of the building. Ancillary and main uses In a number of situations, a building may be used for more than one use. In such situations, it is suitable to classify the different uses as though belonging to its purpose group. When considering other situations, especially in big structures, there can be a multiple blend of uses. In these situations, it is essential to consider the potential danger which one part of a building may expose on the other. Particular actions to lessen the hazard may therefore be essential. The following table shows the classification of purpose groups. (Approved Document B - Fire Safety, 2004). Categorization of purpose groups TITLE GROUP INTENDED PURPOSE OF THE BUILDING Residential ( Dwelling places) 1(a) 1(b) 1(c) Flat Dwelling houses containing a storey that is habitable and a floor level that lies over 4.5 meters above the ground level Dwelling houses that do not have a storey that is habitable which has a floor level lying over 4.5 meters above the ground level. Residential (institution) (others) 2(a) 2(b) Home, school, hospital or any other enterprise used for treatment, as living place or for care or maintenance of people under the age of 5 years. They may be with disabilities or suffering from illnesses, old age or mental and physical incapacity. The building may also include places of legal detention where such people sleep in the building. Boarding houses, residential colleges,hotels,hostels and any other residential purpose that is not described in group 2(a) office 3 Offices and premises utilized for administration purposes, clerical work, handling money and communications or television, radio, film, audio and video recording and their control. Shops and commercial 4 Shops and areas utilized for retail trade, businesses and areas where the members of the public collect or deliver goods. This may be concerning repair, hire or other treatment of the goods, or where individuals may carry out the repairs and treatments themselves. Assembly and recreation 5 Places of recreation, assembly, or entertainment. These include bingo halls, film studios that are open to the public, amusement arcades, dance halls, casinos, museums, art galleries, concert halls, swimming pool buildings, sports stadiums, law courts, places of worship, libraries, health centers, passenger stations, menageries and zoos. Industrial 6 Factories and other areas utilized for repairing, manufacturing, washing, cleaning, breaking-up, altering or processing of any object (Jain 2007). Areas used for generating power or for slaughtering livestock. Title Group Intended purpose of the building Storage plus other non-residential 7(a) 7(b) Places for the deposit or storage of goods and materials as well as any construction not lying within purpose group 1 to 6 Car parks that are intended to only accommodate motorcycles, passenger and light good vehicles that weigh less 2500kg gross SECTION 3: Escape Route Design Large quantities of hot gases and toxic smoke are produced when a fire occurs in a building which travel extensive distances within a building and present a direct threat to life. Visibility of the escape route is also greatly affected by the smoke which affects the ease of escaping within and from the building. Therefore, escape routes should be well designed to ensure easy visibility and should not be affected by the smoke (Nolan, 2010). This can be attained by fitting emergency lighting to ensure that there is enough light in the event of fire. The escape routes should ensure that the occupants of a building on fire do not necessarily need help from out side, but they can find their way out of the building. Where possible, a number of escape routes should be available which allow for ease of escape to safety. In case of a building with several floors, each floor should be provided with alternative escape routes which will help reduce congestion and one escape route may become unavailable for use. The escape routes should be scattered and remote from each other to provide alternative routs. The number of escape routes to be put in place in a storey building is influenced by the capacity of those routes to evacuate each area while still considering the possibility of an escape route not being available for use as a result of the fire. The floor layout with respect to the distance to be traveled also influences the number of escape routes required. The amount of occupants used will usually be specified based on the design of the escape route. When the exact number of individuals expected to use a building or floor is unknown, the number of escape routes should be designed on the basis of suitable floor space factors (Bett, Hoehnke and Robinson, 2003). The table below gives the least amount number of escape paths from a building or storey depending on the number of occupants. (This figure should be enlarged by the need to observe trek distance and other realistic considerations.) Maximum number of occupants Minimum number of escape routes 60 1 600 2 More than 600 3 All doors on the escape path should be opened in the direction of escape. The doors should not open on the direction from which people are escaping from. Doors also ought not to be open across stairways, or block the required width of the escape corridor, lobbies or landings when opened. Exit doors should be opened at all times (Anon, 2006). The height of the escape routes are supposed to have minimum and clear headroom of 2.0 meters from the floor to the ceiling and should have no obstruction or projection, except a door frame, below this height. Horizontal escape routes Horizontal escape routes are mostly applicable in single storey buildings. This escape routes may be considered in two stages which are travel within rooms and horizontal travel from rooms to a place of relative safety or to a final exit. Horizontal evacuation requires those areas used for the care of the residents to be subdivided into confined areas that are separated by compartment walls as well as floors. This allows horizontal escape to be made by evacuating into neighboring secluded areas. In case of a storey building, each storey should be divided into at least three protected areas by compartment walls and floors. Every protected area should be provided with at least two exists. The greatest travel distance from whichever point to a protected area must not be more than 64 meters to a storey exit or main door (Reid, 1984). Travel Distance The availability of alternative escape routes should be taken into consideration when deciding the distance traveled to an escape route from any point in a building. Where the distance to be traveled is long, there should be alternative escape routes where travel from any point can be made in more than one direction (Billinton, Ferguson and Copping, 2002). With short travel distances, escape can be made in one direction only also referred to as dead-end travel. The routes of escape from whichever floor ought to be of certain figure and should also be positioned in a way that the trek distance from any position to the nearest exit does not go beyond the suitable set restrictions. The table below shows the maximum distance of travel in small buildings with a protected stair. Floor Maximum Distance to be Traveled Ground floor with single door 27 meters Basement or first floor with single stair 18 meters Floor with more than one exit stair 45 meters Where possible, the division of the floor area should be avoided at all costs to ensure that exits are visible. This will also ensure that the trek distance from any position of the floor to the available exits is kept at its minimum. The floors of the hallways, lobbies, landings in addition to stairways which form part of the escape route should not be made of slippery surfaces. Buildings should also comply with the Technical Guidance Document of building regulations, 1991 which provides that ramps should be provided for use by physically handicapped persons. Width of Exits Escape routes should be satisfactorily wide to facilitate evacuation of the building, while still considering the physical conditions of the occupants of the building and the method to be used to evacuate. The width of way outs and escape routes depend on the figure of people who will be using them. The table below gives the width to be used for a specific number of occupants. (Guidance of the spacing of seats for the lecture hall is as given in BS 5588-6: 1991) Maximum number of occupants Minimum width in millimeters 60 750 110 850 220 1050 More than 220 5 millimeters per occupant In a situation where the highest figure of residents expected to make use of an escape path and way out is indefinite, the correct aptitude should be considered on the basis of the occupant’s aptitude. The escape stairways should have a width of 1150 millimeters, but not less than 900 millimeters. The width of the escape stairways will depend on the method likely to be used for evacuation purposes (Polley, 2009). When choosing the total width of the exits, the biggest exit should be discounted, which may have implications on the breadth of the stairs since they must be as wide as the exits leading onto them. The overall number of people which two or more accessible exits (that is after discounting) can accommodate is established by adding up the highest number of people that can be accommodated by each width. For example, 3 exit each being 850 millimeters wide will provide accommodation for 3*110=330 occupants (not the 510 occupants accommodated by one exit 2550 millimeters wide). Where the way out of a ground floor shares a way out with a stair through a ground floor foyer, the breadth of the way out should be enable the greatest evacuation flow rate equivalent to or larger than the one from the floor way out and stair joint. Vertical Escape Routes Vertical escape routes are usually stairs, staircases and ramps. Vertical escape in other words is by way of a secluded stairway to the last exit leading out of the premises at ground or access level. A vital aspect of a means of get away in multi-storey buildings is the accessibility of an adequate number of effectively sized and sheltered escape stairs. Multi-storey buildings may combine both horizontal and vertical escape routes to evacuate the occupants in the occurrence of a fire. Vertical escape routes designed in fire-resisting construction so that it can be protected from smoke and fire. This kind of fire-proofing also hampers the spread of fire among floors. Doors which are fire resistant should also be used for the protection of life in other floors. Stair Provisions It is important that stairs are available for the evacuation of all occupants in a storey building in occurrence of a fire, that they can be used safely at all times. The number of stairs to be used in a building is affected by the height of the building, occupancy and size of the building. The width of the stairs should be adequate to quickly evacuate all the occupants of a premise. In buildings that may be served by only one stairway, the width of the stairs should not be less than 900 millimeters wide, but where the number of occupants of the building is low, the distance across should not be less than 750 millimeters as indicated in BS 5588: Part 1 : 1990. Stairways should be protected by enclosing them in constructions that are fire-resisting or within shafts that are protected so as to shield the escape paths from fire and smoke. Those stairs that are not positioned next to external walls, or that do not have open-able windows, should be provided with suitable automatic smoke ventilation facilities (Anon, n.d). Storage rooms with high fire risks and other fire prom areas ought not to be open directly into a sheltered stairway. Such kinds of areas are supposed to be enclosed by fire-resisting construction and be alienated from the escape routes. A building can be served by a solitary escape stair provided that self-sufficient escape routes are not essential from areas in diverse purpose groups. The number of stairs required should take into consideration the distance travelled from different areas within the building and also buildings with few floors and small numbers of occupants. A small building may make use of a single escape stair excluding bars or restaurants. An office building consisting of less than five floors beyond the ground floor can use a single stair provided that the distance of travel from any point in each storey is 4.5 meters and every storey that is at a height larger than 11 meters has a substitute means of getaway (Billington, Bright and Vaters, 2007). A refuge must be provided at each protected stairway. Refuges are relatively safe places where people can wait for small periods. Therefore, they are not places where disabled people can be left alone for an indefinite period. In a building with over five floors above the ground, the stairway must be separated from the entrance door of each floor by way of a confined lobby onto all levels, apart from the top-most storey. A building which has a basement, the stairway serving it and the ground floor should be alienated from the stair serving the upper floors by 60 minutes fire proofed construction, including automated fire doors at the ground and basement. References Alan, B. Richard C., 2005 The handbook of tunnel fire safety Thomas Telford Anon, 2006. Building Regulations Approved Document B: Fire Safety: Buildings other than Dwelling houses. London: The Stationary Office. Anon, n.d. Fire code-fire safety in the NHS: guidance in the support of functional provision for healthcare premises. Norwich: The Stationary Office. Bett, G., Hoehnke F. and Robinson J., 2003. The Scottish Building Regulations: Explained and Illustrated. 3rd Ed. Oxford: Blackwell Publishers Ltd. Billington, M.J. , Bright, K. and Vaters, J.R., 2007. The Building Regulation: Explained and Illustrated. 13th Ed. Oxford: Blackwell publishing Ltd. Billinton, M.J., Ferguson A. and Copping, A.G., 2002. Means of Escaping from Fire. Oxford: Blackwell Science Ltd. British Standards Institute Staff, 1998 Fire Detection and Fire Alarm Systems. Power Supply Equipment BSI Group British Standards Institute Staff, 2006. 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