Fire Protection in Academic Building - Essay Example

Detection and warning system It is essential that an institutional building such as the Academic Building is fitted with an automatic fire detection and fire alarm system. There are two main reasons for this. The first reason is that it can greatly boost the level of safety in that building, while the second reason is to satisfy the statutory requirements of the United Kingdom government. The Building Regulations of the United Kingdom require all buildings to have a fire detection system in place. It is important to note that a fire detection system in this context refers to an automatically operated network of sensors consisting of related control and indicating devices. The types of sensors vary in the sense that they are responsive to heat, smoke, radiation, or gaseous combustion products. The control and indicating devices operate the fire alarm system. For small and simple buildings, it would be sufficient to detect fire and alert the occupants by means of a person shouting a warning. However, for the Academic Building, a more sophisticated system is required. Automatic fire alarm system It is therefore vital that the Academic Building is installed with an electrically operated fire detection and alarm system. The fire alarm system should include adequate sounders that are clearly audible, and manual call-points located close to the exit doorways. The cautionary signals about the imminence of a fire should be distinguishable from signals for other purposes. A voice alarm system can be used in the Academic Building to address this issue, as well as warn people who are not able to quickly discern the purpose of a fire alarm. It is also important that the fire alarm system is set up in such a way that a discreet alert – such as a paging system, discreet sounder, and other system – informs the building’s fire safety personnel when the system is activated, or when a fire break out. This is significant in allowing the staff (who must be trained) - to conduct safe evacuation without causing panic and other undesirable consequences that may occur if the alarm was sounded generally. The procedures for evacuation should be incorporated in the voice-based alarm systems. It is also important that all alarms are interlinked so that smoke or fire detection by one alarm/detector unit triggers signals for all the alarms. However, it is imperative that the guidance provided by the alarm manufacturer is observed when linking the alarms to avoid linkage of excess units. Smoke and heat detectors Every floor of the academic building should be fitted with at least one smoke alarm. Other crucial areas such as the kitchen and the lab should also be considered for appropriate alarms. It is paramount that a smoke alarm is installed in the circulation space adjacent to the kitchen as well as that adjacent to science lab, because the two represent high risk areas in the building where fire is likely to start. Since there is no door separating the kitchen from the adjacent circulation space in the ground floor of the academic building, a compatible interconnected heat detector and alarm should be installed within the kitchen, besides the smoke alarm in the adjacent circulation space. The location of the smoke detectors is also fundamental. The smoke detectors should be mounted on the ceiling and located at least 300mm away from light fittings and walls. If wall-based alarm units are to be used, then they must be located above the level of the doorways. For ceiling mounted detectors, they should be placed about 25mm to 600mm and 25 to 150mm below the ceiling for smoke and heat detectors respectively. It is crucial to note that the alarms should also not be placed over the stairways or the ramp. Smoke detectors should not be fixed directly above or close to air-conditioning outlet and heaters, as well as in the kitchen and in the garage since they are likely to give false alarms. The cables used for interconnecting the alarms should be easily discernible from those used for power supply. It is also essential that the detection system does not trigger an alarm falsely; that is, when there is no building fire. Such false alarms have been known to occur in cases where a fire/smoke detector, such as an ionization chamber detector, is affected by kitchen fumes. Therefore, it is important to use optical detectors, which are considered more reliable than ionization chamber detectors, and are less affected by, for instance, kitchen fumes (Department for Communities and Local Government 2007 p.18). Power supply It is recommended that a smoke and heat alarms system is powered primarily by the mains electricity supply, but provided with a back up power supply such as a capacitor or a battery. This mains supply should be characterised by an independent circuit derived from the main distribution board, but without separating the lighting, to avoid the chances of being disconnected after a prolonged period of time. The back up power supply can be a capacitor or a battery. Providing a back up or standby power supply ensures that the system remains in operation even when there are power outages with the mains supply. Warning devices for people with disabilities Some parts of the building, especially where it is probable that people with impaired hearing can be present in isolation, should be fitted with fire warning system that is able to alert such people. A vibrating paging system is the most suitable for this building since the inhabitants are usually controlled (Department for Communities and Local Government 2007, p.21). Areas in the Academic Building where such cases are likely to happen and, therefore, are candidates for the installation of such devices are in the basement, offices, classroom, lecture rooms, and the study area. Furthermore, the paging system is suitable in alerting persons with other kinds of disabilities. Means of escape This report identifies two distinct aspects of the means of escape from the Academic Buildings: escape from within a room and escape from a room to the final building exit. However, there are few cases that require planning for escape from within a room since there few instances of inner rooms in the building. Inner rooms The number of inner rooms in the Academic Building is countable, but there is need to plan for egress in these rooms. The inner rooms include the furniture storage in ground floor, water closet (WC) room adjacent to stair number 3 on the first floor to the third floor, exam store on the second floor, language/IT lab on second floor, and cleaner room and IT hub on third floor. While the inner room arrangements for the water closet, furniture storage, and the cleaner room are acceptable, the language/IT lab and the IT hub present a weakness in fire safety design. The travel distance from any point in the inner room to egress from the access rooms should not exceed 9 meters. Other conditions of the inner rooms are in line with the Building Regulation requirements. The inner rooms should also be installed with an appropriate automatic fire detection and alarm system. The capacity of occupants of these inners rooms should not be more than 30 people. Balconies and galleries The balconies or galleries in the Academic Building are designed in accordance with the fire safety regulation regarding egress from a building. The galleries have an alternative exit besides the two stairways, which are also readily accessible from the gallery. In addition, the galleries have adequate guarding through balustrade. The means of escape in the ground floor are also designed appropriately since rooms open directly to the exit corridor, or have a door that is suitable for egress. Protected area It is important that exit routes for the building area protected from fire and smoke. The exit routes include the stairways and lifts, although lifts should not be used as means of escape. It is also necessary t install a sprinkler system. It is however necessary to take precautionary measures to avoid the likelihood of air circulation systems allowing fire or smoke to spread into the protected area. The measures include the following (Department for Communities and Local Government 2007, p.26): Avoid installation of transfer grills in door, walls, ceiling or floor surrounding the protected stairway. If there are ducts crossing through the protected stairway enclosure, then they should be made of rigid steel, and joints between the enclosure and the ductwork should be fire-stopped. Ventilation ducts for direct supply and extraction of air to and from the protected stairways should not serve other parts. Any mechanical ventilation system for circulating air into the stairways should be able to shut down when smoke is detected in the system. . Common lobbies and corridors The common lobby and corridors to various rooms in the building should be protected. These include the common corridor adjacent to the counselling room, and the lobby serving the kitchen and other adjacent rooms, including the office on the ground floor. The lobbies on stairway number 2 and stairway number 3 as well as the common lobby serving the two language/IT labs in the first floor of the Academic Building should be protected. The common corridor serving the staff room and prep, and adjacent rooms, as well as the corridor leading to stairway number 3 on the second floor is also subject to such protection. The same applies to common corridor adjacent to staff work room, and the lobbies for stairway number 2 and 3 on the third floor of the building. All the lobbies and corridors in the basement also qualify for protection. It is also necessary to provide a way for ventilating these common lobby and corridors to control smoke that may spread from open doors of adjacent rooms. This would not only protect the lobbies and corridors, but would also prevent smoke from spreading to the exit stairs. The ventilation can be achieved through either mechanical ventilation or by natural means. The stairway linking directly to the main corridors separating the two sides of the building and which extend to form the gallery portions of the building in the first to the third floors should have self-closing doors. The doors to the lobby and corridors leading to the stairways number 2 and 3 of level 1 to level 4 should also be self-locking. It is important that these doors are constructed in such a way that smoke would not affect entry to more than one stairway. The doors separating the common lobbies and corridors from the main corridors/galleries in various floors should be maintained. The common stairs – vertical escape The number of common stairs for exiting the building is acceptable in regards to fire safety. The common stairs should be at least 1000mm wide and provided with fire protection measures of suitable standard. In addition, while the common stairs are situated within enclosures as required for fire safety, these enclosures should be fire resistant. This minimizes the risk of heat and smoke causing the use of the stairs hazardous. Electricity meters situated within the stairways should have a secure cupboard enclosure that is separated from the stairway (egress) by fire-resisting structures. However, it is advisable to avoid installing such meters on the stairway, as well as avoid installation and gas pipes in he protected stairway. The number of vertical escape routes (the three stairways) is acceptable for fire safety. The building can hold about 780 people per floor. The building Regulation recommends about 3 exits for about 600 and above in each storey (Department for Communities and Local Government (2007, p.35). The two stairways leading to the basement are properly designed as recommended by the Department for Communities and Local Government (2007, p.31) that there should be at least one stairway from the upper floors that is terminated at the ground; the stairway number 2 terminates at the ground floor and does not extend to the basement. The escape routes, including the stairways, the lobbies and corridors should have a lighting system other the mains electricity, so that there is illumination even when the mains fail. Horizontal and vertical escape The determination of the number of exits and routes for fire escape is largely based on the number of occupants in a storey or room, and the limits on travel-distance to the closest egress. The maximum travel distance for the main corridor to any of the three stairways should be reduced to about 18 meters. The corridor provides more than one direction to the escape routes and exits. Other horizontal escape routes in the rest of the building are within the recommended travel distance of about 9 meters for one direction travel (Department for Communities and Local Government (2007, p.33). The common corridor in each floor of the building should be fire protected. The headroom of every escape route, except in doorways, should not be less than 2 meters. The minimum width for each escape route should be about w = 1242 mm, where exit capacity for each stairway is about 390 people. This allows all the 780 occupants of the building to be accommodate by at least two of the stairways, so that in case one stairway is blocked, the rest can adequately support the population. (The calculations for these values are shown in appendix 1). However, the undiscounted capacity for three stairways is about 1170 people. Refuges There is also the need to provide adequate refuges for the three stairways in accordance with the number of people who might be using wheelchairs on the building. The refugee area should be at least 900mm x 1400 mm, which is adequate for a wheelchair user to wait on assistance. The refuge should however not impede the escape route. An emergency voice communication (EVC) should also be installed for refuge users. The refuge should also be labelled with a blue phrase “Refuge – Keep clear.” Internal fire spread linings It is also essential that the Academic Building has appropriate internal linings. The linings should be able to sufficiently resist fire spread over their surface, and, if ignited, their fire growth rate or heat release rate should be reasonable. The type of materials used for internal walls and ceiling can substantially influence a fire spread as well as its rate of growth. The internal linings used for the Academic Building should satisfy a number of specifications requirements. The linings for the small rooms with area not exceeding 30m2 should belong to class 3 of the national classification of linings, or the European class D-s3, d2). The linings for the circulation spaces including common corridors and lobby, and stairways should belong to class 1 (of national classification) or class B-s3, d2 of European classification. However, it is apparent that most of the rooms, including lecture theatre, classroom, study room, admission and marketing office, and all labs, among other rooms each have an area of more than 30m2. Therefore, any lining used in these rooms should have a fire rating of class 1 of national classification (or European class C-s3, d2), or of higher performance. There are specific provisions, nonetheless, that endorse the use of linings materials that do not fall under the classes specified above for the two general situations. Walls and windows Lining of walls for the Academic Building that do not fall under the above classes for the corresponding category of room sizes can be used. However, the total area of such lining in any single room must not be more than half the room’s floor area, and the room must not exceed 60m2. It is worth to note that a wall in the context of this document does not refer to doors and their frames, windows and their frames, skirting, fireplace surrounds, fitted furniture, and similar components. Also, a wall that is inclined at an angle of 70° is classified under ceiling. Thermoplastic materials used for internal glazing of windows or walls must be rated under class one (1). For external window and walls the thermoplastic material must be classed as TP (a) rigid. Ceilings and roof lights Suspended ceilings should be adequately fire protected. Either fire resistance materials of class 1 or of European class equivalent (C-s3, d2), or cavity barriers on concealed spaces of roofs (and floors) should be used. Plastic roof lights should be generally avoided for the Academic Building. However, if they are to be used, they should have a rating of class 1 standard or higher. The roof lights, especially in protected stairways, should not be made of thermoplastic materials. However, thermoplastic roof lights can be used in circulation spaces (such as corridors and lobbies leading to exits) and rooms provided that they are classified as either TP (a), or TP (b) rigid. It is worth to note that thermoplastic linings should not be used in the protected stairways and circulation spaces. Moreover, thermoplastic materials are generally discouraged for use as internal lining. Thermoplastic lighting diffusers should be avoided, and if they are to be used the area in which they would be incorporated must be adequately fire protected, and the diffusers must be of class TP (a) or TP (b) rigid. The installation of TP (b) class diffusers should however be minimal. These diffusers should not be used in the stairways. Internal fire spread structure Reference list Department for Communities and Local Government (UK) 2007, The building regulations 2000: fire safety approved document B volume 2 - buildings other than dwelling houses. National Building Specification, United Kingdom. Appendix 1 – means of escape calculations The number of occupant in the building (No) is given by dividing the footprint area (780m2) by a floor area factor that is in m3 per person. The floor area factor for the Academic Building is equivalent to about 1.0 m3 per person (Department for Communities and Local Government 2007, p. 134). The footprint for the Academic Building is 780 m3. Therefore, No = 780/1 = approximately 780 people The capacity and width for stairs is given by the following formula (Department for Communities and Local Government 2007, p. 48). P = 200w + 50 (w - 0.3) (n - 1), or w = (P + 15n – 15) / (150 + 50m) where P represents the number of people served by the escape route, w is the width of the stair, and n is the number of floor (storeys) served by the escape route. Therefore, the width of the stairways (w) should be as follows: P = 780 / 2 = 390, while n = 4 w = 780 + [(15 * 4) - 15] / 150 + (50 *4 ) (390+ 60 -15) / (150 + 200) 435 / 350 w = 1242 mm Note that this represents the total width of one stairway such that two of the three stairs can serve the whole population satisfactorily when access to one stairway is blocked. This is a recommendation of the Building Regulation (Department for Communities and Local Government 2007, p. 134). Thus, the total undiscounted capacity for the three stairways is a follows: 390 * 3 = 1170 people Read More