Fire Protection Strategy: Means of Escape for Academic Building - Report Example

ACADEMIC BUILDING Means of Escape 1. Introduction A significant number of people lost their lives or injured while escaping from fire and most of them died by either smoke inhalation or burn. For this reason, a number of strategies were created to provide adequate means of escape in building. The ability to turn away from fire and escape through a safe route is essential because this could save a considerable number of lives during a fire. Similarly, the design of means of escape is important thus law requires building owners to conduct a risk assessment of their facilities and ensure the adequacy of means of escape. During a fire, people should be able to get out of the building the soonest possible time thus design of means of escape should consider the shortest escape routes. More importantly, the design must take into account the reaction time and the number of people that would escape at the same time. The following sections discuss the various requirements of means of escape according to BS 9999 and Building Regulations 2000 or Approved Document B Volume 2 for Buildings other than Dwelling houses. More importantly, it will cover means of escape design issues in academic building and provide recommendations to enhance safety of people escaping during a fire. 2. Background The owner of the new Academic Building is looking for a way to reduce the cost of fire protection system thus the design should avoid costly fire sprinklers as much as possible. In addition, the owner specifically instructed that no alterations should be made on the existing fire alarm systems or any building nearby. The general requirement therefore is to assess and present specific design issues concerning means of escape in the new academic building. Designed resembling an atrium building with large space and balcony in the upper floors, the new Academic Building include facilities such as lecture theatre and classrooms, cafe or dining, group workspaces, laboratory for science and information technology facilities, offices for staff and other basic facilities. Aside from the basement, building has other floors, the basement, ground, first, second, and third floor. Overall, there are five levels to consider in the design of means of escape and each level must assess and analysed. The building dimension is approximately 46m x 25m while a number of voids are linking the ground floor to the highest floor. The new Academic Building will be built inside the University Campus with a north elevation 5.5 metres of the university’s History Building. The new building will be located at about 11.5 metres from the centre of the main road in the east and 17 metres to elevation of Arts Building in the South. In the west elevation, the site boundary is less than 40 metres. 3. Means of Escape As mentioned in the introduction of this report, the design of means of escape should be based on a risk assessment of the building. For this reason, it is necessary to examine and analyse the plan of the new Academic Building. To make the risk assessment convenient, it is necessary to identify parts of the building that are not acceptable as escape routes. According to the Communities and Local government’s Approved Document B, although they may appear a convenient way to escape out of the building, design of escape routes should not include lifts, garbage chutes, portable ladders, and other similar items (Communities and Local Government 2000, p.16). Lifts are not include because of the reality that it is powered by electricity and anytime during a fire, escaping people may be trapped inside the lift due to power failure. More importantly, smoke may penetrate the lift and affect the people inside the lift. Similarly, portable ladders are unstable and may contribute to further injury during an escape. Garbage chutes is not for people as the name implies and during an escape, people may get hurt sliding down the chute particularly from the upper level. Building Regulation 2000 for buildings other than dwelling houses recognised the reality of fire in an occupied building thus recommending an alternative means of escape. An alternative means of escape is necessary to ensure that whenever the designated primary escape route rendered impassable by fire or smoke, people can turn around and take another route to safety. Another recommendation is to include provisions for a ‘place of relative safety’ where people can go when escape to a place of absolutely place of safety outside the building is temporarily unavailable due to smoke, fire, and other reasons. Escape route is divided into two essential categories – the area that is fire and smoke protected and those that is not. Protected areas are those with walls and doors that are fire-resistant and mostly located near stairways where escape or evacuation can proceed in its own pace. In contrast, unprotected escape routes are those areas that are critical and exposed to the danger of fire and smoke. These are the areas that escaping occupants should negotiate in the soonest possible time to avoid injury. Unprotected escape routes are usually few metres long and connected to a protected area or place of relative safety (Communities and Local Government 2000, p.17). There are guidelines being provided by the British Standard for the design of escape routes and most of them can be found on BS 9999:2008 or the Code of Practice for Fire Safety in the Design, Management, and use of Buildings. BS 9999 :2008 contains important specifications concerning escape route design that include specifications for flooring, ramps, and landings use in escape, the size of the means of escape, specifications for refuge, and maintenance of escape routes. According to BS 9999:2008, it is very important that floors, ramps, landings, and other areas leading to the absolute place of safety are slip resistant. This is because escaping people may slip and get injured while escaping. Slipping can also delay evacuation thus design of floors and other items along the escape route must consider these possibilities. Another consideration should be given to the number of people that would pass the escape route at the same time. The size of the escape routes may not be enough for people to pass freely particularly when emergency responders are also entering the building through the same escape route at the same time. Moreover, escape routes must be design not only to accommodate a significant number of people but to accommodate disabled person who may have difficulty escaping. BS 9999:2008 provides specifications for safe refuge area where disabled people can temporarily stay while waiting for rescue or assistance. These refuge are according to standard should have clear markings or signs, facility to communicate, and handrails to avoid injury. Maintenance of escape routes is key to successful evacuation and according to the standard; the management of the building should ensure that all escape routes are free from obstacles. These include critical areas of the escape routes such as stairs, doors, corridors, and others. As oppose to the use of lifts, portable ladders, chutes, and others, the British Standard for means of escape specified only three acceptable means of escape. These are any door that can provide direct escape or any door that can provide escaping people access to protected areas such as refuge and protected stairway, or stairs that are protected by fire-resisting materials (BS 9999 2008, p/.48; p.60; 93). The principle of means of escape generally emphasizes the relationship between “fire threat and time” (BS 9999, 2008, p.53). There are four important stages in means of escape and these include the time to detect the fire, the time before an occupant react, the time it takes for the occupant to reach the place of relative safety, and their movement within the place of relative safety. The occupant’s response and travel time starts with ignition, the time it takes to trigger the alarm, the alarm itself, and the time before an occupant respond to the alarm or pre-movement time. During an escape, the available safe escape time or ASET should be taken into account (see Figure 1) along with allowable travel time and tenability limits. Following specifications contained in BS 9999:2008, a standard classroom can conveniently accommodate two average people per square metre while three may be consider in large rooms such as science laboratories and others. Similarly, the number of exit route is dependent on the total number of people occupying a floor. For instance, if the floor contains 600 occupants then two exit route may be considered while additional exit route may be required if 600 people or more. This may be computed by assuming a minimum of one exit route for 60 people at the same time (see Table 11 of BS 9999:2008 on 70). Similarly, alternative escape routes should follow the specifications and should be 45 degrees apart from each other. However, if the other alternative escape routes are less than 45 degrees, they should be separated by fire-resisting construction with self-closing fire doors when necessary (BS 9999 2008, p. 70-71). Corridors providing access to alternative escape routes should not be more than 12 metres long since the risk of smoke spreading may make escape routes impassable. In case long corridors are unavoidable, each corridor must be separated by self-closing fire doors (BS 9999 2008, p.75). 4. Assessment and Critical Analysis 4.1 Basement Referring to the new Academic Building’s basement plan, one stair leading to the ground floor can be use a primary means of escape. The stair near the lecture theatre also leading to the ground floor can be use an alternative provided that it will be part of the protected stairs system. Similarly, the primary escape route selected should be protected by fire-resisting structures including fire-rated doors. As mentioned earlier, BS 9999:2008 requires primary escape route floors and stairs to be slip-resistant thus provisions for such finishes must be included. More importantly, escape route leading to either primary or alternative escape routes should be clearly marked with appropriate signage such as arrows and exit signs. Marking escape routes is necessary as occupants during a fire may be confuse and take the wrong way out of the building. Since the lift near the storeroom is disregarded as a possible escape route, the area around the stairs should be protected including the swing doors at the lobby (see marked basement plan for details). 4.2 Ground Floor Escaping from the ground floor may not be problem compared to upper level floors and there are several convenient escape routes that can be taken. However, the ground floor will be part of the overall means of escape for the building and will be use by escaping occupants of the upper level floors with the exemption of those who will take stair no. 3 that is directly connected outside the building. For the occupants taking the alternative escape route, the Group Workspace area is the most convenient escape routes as they only need to travel around 11 to 12 metres across the space to reach absolute place of safety. Alternative escape routes for people occupying the counselling and student services rooms, the waiting area, reception, and some people from is stair no. 2 as it is adequately protected by a number of doors and thick construction. From the WC and kitchen area, people can take the corridor leading directly to the outside of the building since the travel distance from their location is shorter than travelling across the workgroup space. From the dining area, the most convenient and safe escape is to travel across wide open space offered by the workgroup area because the number of people from this area may be considerable large compared to other area of the building. 4.3 First Floor Depending on the location of escaping occupants, two primary escape routes can be selected. Stairs 1 and 2 can serve as primary escape route for the second floor occupants as it leads directly to the ground floor and place of absolute safety. However, these escape routes must maintain its integrity and retain the refuge area and fire-resistant doors. The building plan seems to anticipate the presence and the need for giving disable people a place to stay in case of fire. As indicated, there are refuge areas provided on stairs 1 and 2. The corridor along the classrooms which is less than 12 metres in length may be use as alternative escape route as it leads directly to a stair. However, as per plan, there is no indication that this stair is protected. There is a need to enclosed this stair with fire-resisting walls with self-closing doors (see plan for first floor for details). Provided that the stair is enclosed, occupants of lecture rooms can use this as their primary escape route to reach the ground floor, travel across the workgroup area, and outside the building. 4.4 Second Floor Similar to the first floor, the second floor has the advantage of having two protected escape routes leading directly to the ground floor and outside the building. However, since the possibility of fire rendering these escape routes impassable (for instance fire occurring at the staff room) an alternative escape route is required. This alternative escape routes should use the corridor leading to an enclosed protected stair (see second floor plan). Students in the IT Laboratory can use this protected stairway on their way to first and ground floor. Disabled people can use the refuge provided in stairs 1 and 2 whichever is available. Similarly, it may be convenient for occupants in the inner lecture room to take the protected stairs as it is much shorter than travelling across a narrow and longer corridor (approximately 12 metres from door 320) near the refuge area leading to stair no. 1. 4.5 Third Floor Similar to first and second floor, third floor occupants can use stairs 1 and 2 as their primary escape route whichever is available during a fire. However, it may best to enclose the stairs with fire-resisting materials and self-closing fire-rated doors as an alternative route through the stair near the lift is possible. Since there a large number of people will be occupying the Individual Study Area and Lecture Room, this stair could serve (if protected) as an alternative route as it the travel distance is shorter and escape may be faster. 5. Conclusion Aside from the absence of clear alternative escape routes and provisions for enclosed protected stairs, the new Academic Building plan provided a safe escape route by providing a fully protected stairs 1 and 2. However, using one as primary and making the other alternative may not be a sound solution because when an area near these stairs caught fire, that particular escape route will be impassable. It is therefore necessary to establish another alternative route that can provide similar safe passage. The existing unprotected stairs can be enhanced by constructing fire-resisting walls around the stairs. Each side of the wall will have self-closing fire-rated doors to ensure that escaping people from the third to ground floor or from the basement to ground floor is protected. 6. Reference list BS 9999, 2008, Code of Practice for Fire Safety in the design, management and use of buildings, BSI British Standards, BSI, UK Communities and Local Government, 2000, The Building Regulations 2000, Fire Safety: Approved Document B, Volume 2- Buildings Other than Dwelling Houses, Communities and Local Government Publications, UK Read More