Application of the UK Fire Safety Engineering - Assignment Example

Application of the UK fire safety engineering to apartment building design for means of escape Name: Course: Instructor: Date: Introduction: The management of fire and safety within buildings is an important process. In the UK, the government provides standards that are applicable in the design of new buildings and material alterations to existing buildings. These standards are intended to safeguard the occupants of a building from injuries in the event of fire and hopefully assist firefighters in accessing the building. Causes of fires are mainly electrical installations or explosions from the use of flammable chemicals. However, extreme events like terrorist attacks can also lead to fires in a building. The British standards do not cover the design for safety in the event of such extreme scenarios such as a terrorist invasion (Thenbs.com, 2015). This is due to their undefined nature. As a requirement, the design of the building should allow for easy horizontal escape in a fire situation. The British standards require that at an instance of a fire, a person should leave the building without being blocked by the fire or smoke. This should be achieved by moving in a single direction away from the fire. This implies that there should be a couple of exits to a building that occupants can use to exits the building to safety. In some instances, the standard permits the existence of a single escape route. However, the provision of an alternative route is important to avoid the population of the house from being trapped by congestion of the escapes. The number of tenants in a building therefore becomes an important factor in designing for escape. Additionally, the indented use of the building will also affects the number and distance from the exit doors. This paper gives a review of the design specifications that are expected in escape instances in buildings in the UK. It intends to show how the UK building standards that are contained in the approved document B affect the specifications of the buildings designed in the country. Evacuation strategies In simple buildings, upon the discovery of fire, each individual will require to move from the fire zone to a more secure location. This can happen simultaneously and can include all the occupants of the building. There should be alternative exits available to the people inside a building. For instance the building design below, the escape routes are given in green. There are numerous exits to o the building and an individual at each point can take optional exits through the corridors. All the corridors have two or more exits according to the design plan bellow. This method of evacuation is called the simultaneous evacuation. After the warning is given, everyone walks out the building through exits. The major exits should be designed to carry a large number of people. Doors opening towards the outside of the building can be helpful in times of emergency with easy opening or break through. The major exits can also have double doors to cater for the huge population that are likely to use it simultaneously at an instance of a fire within the building. The horizontal phase evacuation A horizontal evacuation is the process of simply moving the occupants horizontally to a place of safety (Flin, 1997). In non-storey buildings, occupants can easily exit the building by moving through the corridors into the exits. In tall buildings, horizontal evacuation is not easy. The challenge that is mostly associated with story buildings is the use of lifts and stairways as means of exiting the building. The lifts present a number of issues in such emergencies such as the congestion in the lifts which can lead to occupants suffocating in the little space. The lift system can also fail to work leading to the occupants being trapped for a longer period in the building with a fire emergency. A horizontal evacuation is possible in the buildings through a sky bridge. Linking two towers with a sky bridge will make it easier for the occupants to exit the building with a fire through the elevators in the other tower. Progressive horizontal evacuation In case the occupants of a building are dependent on the staff like in the hospital situation, progressive horizontal evacuation technique is the most appropriate. In this technique, the occupants are moved to other zones within a short distance from the risk of fire. These zones are compartments within the building that are designed with fire resistance materials. This strategy aims at reducing the amount of movement that the occupants of the building will be subjected to in the event of a fire. It also moves the occupants of the building to reasonable safety with ease. As a requirement, the building should be divided in a series of compartments that can resist fires. The aim of the division is to reduce the possibility of the progression of the fire and to give time to occupants of other rooms to escape. Occupants of other compartments remote from the beginning of the fire may note leave the building. However if the fire shows likelihood of spreading to other compartments including the remote partitions, movement to safety will be required. The idea of compartments is important in managing the impacts of the fire. Through the compartments, the spread of the smoke from one compartment to another is limited. This gives ample time for the occupants to leave the building without the effects of the smoke. It also makes dealing with the fire fairly simple. The reduction of the possible damage to the building is also an advantage of the compartments. In instances where the occupants of a building are not in a position to leave the building even under a fire, the defend in place strategy is applicable. The use of secure compartments can aid the process of defending against the fire while not leaving the building. The containment of the fire is a major requirement that such buildings should provide. This will prevent the ability of the fire to reach other compartments while it is fire fighters are handling it. The distribution of smoke within the building is another challenge in the process. Proper ventilation can help in dealing with the effect of smoke in building fires. The owners of the premise can install ventilation equipment that replenishes the flow of fresh air within the building or opt for natural ventilation. Design for vertical escape External stairway is the most common escape route in storey buildings. This is due to the fact that lifts and other elevators can suffer from power failure in the fire event causing occupants to be trapped. In the absence of an external staircase, the design of the building can include a protected staircase that leads to a safety exit. The staircase should have the door leading to it and other facilities made from fire proof material. The protected stairway should also have a refuge. This is a protected enclosure that is made by fireproof material. In the event of fire in a building, disabled occupants can use this space to wait for assistance. The minimum dimensions of the refuge should be at least 14 by 9 meters. However, this size can be increased if the number of occupants of the building is high rise building (Office of the deputy prime minister, 2000). A refuge has several advantages if implemented in a building. It will reduce the potential of smoke filling the stairway as it gives additional room. The refuge can also act as a fire fighting base where the activities of putting out the fire are coordinated. Evacuees who are injured can also take a rest at the refuges while waiting for assistance. Staircases that are used for ordinary access to buildings are normally 24 inches wide. This kind of staircase can provide access to a maximum of two people walking side by side. A bigger dimension is required for a bigger number of people. This bearing in mind that at the time of the emergency, the number of people that will use the stairs a means of evacuation is more than the ordinary access. An escape stair way should be at least 50 inches wide. This aims at reducing the risk of bottlenecks during evacuation. The side of the stairs with no wall should also be protected by rails. This will reduce the chances of the accidents during the evacuation procedure. The staircase should be kept clear and free from obstruction. Access of the escape stairs should also be made easy from the rooms in the building. For instance, a common corridor that leads to the staircase can be considered in the design of the building. In case a common corridor is not in the plan of the building, it is necessary to have more than one escape staircase. This will prevent the likelihood of other occupants being blocked by the fire from accessing the staircase. The diagram below represents how an injured victim can be moved from a building. The movement requires the staircase to be large enough to accommodate the other users as they exit the building. Image courtesy of https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcREd0BYWnMyD-rMOIiKfj-9ajhhBF5l79T45CaFIj4qCR0Dr70p9A The number of occupants affects the number of exits to a building. For a minimum of 60 occupants, a single exit is an adequate provision that will enable safe escape in emergencies. However, as the number of occupants increase, the exits should also be provided to increase the chances of safe exit without injuries. In storey building, exits can be increased through the external stairs and sky bridges. The increase in number of occupants also affects the size of the stairway. A small stairway will inhibit the free movement of people between any two floors in the building. In cases where the design has given the stairway very small size, only one or two individuals can walk on it at any given point. This limited number would be disastrous in a fire event at one of the floors. In determining the width of the stairway, the number of occupants in one floor of the building is the major determining factor. Maximum number of persons Minimum number of escape routes/ exits 60 1 600 2 More than 600 3 Lifts are rarely used in vertical escape from fires. This is mainly due to the fact that power failures can lead to the occupants being trapped in the lift. However, if is used as an escape lift, they should properly marked as escape routes. The lift should also have a lobby that is made from materials that are fireproof. Design for horizontal escape building other than flats In most buildings the number of escape routes depends on the number of occupants of the building. In case this number is unknown, the calculations can be done using the amount of floor space of the building It is also affected by the type of use to the building and the expected. The nearest exit should limit the distance travelled by occupants at an onset of an emergency. The table below summarizes some of the use of buildings and the maximum travel distance to the nearest exit. The limitations on the travel distance only cover the nearest exit but other exits can be further as provided by the design of the building. Use of the building Maximum travel distance to exit Institutional 9 Residential I. In bedrooms II. In bedroom corridors III. Elsewhere 9 9 18 Shop and commercial 18 Industrial I. Normal hazard II. Higher hazard 25 12 Storage and non residential I. Normal hazard II. Higher hazard 25 12 Assembly and recreation I. Buildings primarily designed for the disabled II. Areas of row seating III. Others 9 15 18 These distances are given as straight distances between the furthest ends of the room to the exit. Depending on the layout of the building, it is possible that no straight distances exist in the building. For purposes of the regulation, the distance is given as two thirds of the total travel distance. An alternative exits can exist within a building but could be further than these distances provided. In an emergency, the occupants have to decide which of the two exits to use. The ability to make this selection will depend on whether both or one of the exits has been disabled. In order to prevent the exits from being disabled all at the same time, the exits should be placed in about 45o to each other. The materials that keep the exit open should be made from fire resisting objects to ensure the exits will be kept open in a fire. The regulations also provide for the access to inner rooms. An inner room is defined as a room that is accessed through another room. Should fire start in the room that is used to access it then an escape route would be blocked. Such settings should be avoid but is possible if the occupants of the inner room do not exceed 60. In case the use of the building is institutional, this number is reduced to 30. In case of a residential property, the inner room should not be a bedroom. The fire safety risk assessment provides that educational premises should have not have less than 1050mm in their escape route. In the dead ends of buildings that will be used for the same purposes, the exit openings should be more than 1600mm. in areas of normal risk, the capacity of the exit or escape root up to 75 cm can take care of 100 persons. If the exit is over 105 cm an additional 7.5 cm raises the capacity of the exit by up to a maximum of 15 individuals. Alternative exits Alternative exits should be placed at angles of more than 45o to each other. The idea behind this fact is that the design seeks to avoid a situation in which all the exits are disabled at the same time in the event of a fire. During the process of calculating the exit capacity of a building, the general assumption is that the fire will prevent exit through one of the doors. It is therefore thought that the alternative door to the blocked exit will be used by occupants of the building. Furthermore, a double door exits is not classified as alternative exit. This is due to the fact that the exit is in a single place and the ability to leave the building using this door can be hindered in the event of a fire. It provides no additional rout to the occupants. In a case where the exits discharge in one common area within a set of buildings or flat, the exits are not treated as alternative to each other. This is due to the fact that in case of a fire at the common area, all this exits will be disabled simultaneously. Their use as alternatives to each other will be lost. From this discussion, escape routes that are to be classified as alternative to each other must therefore be above 45o while viewed from the furthest part of the room and should not discharge the occupants in a common area. Facilities for people with disabilities The accessibility of the building by disabled members is the major concern of designers when developing the plan of a building. A proper design would include ramps that will aid the use of wheel chair by the disabled to access the various compartments of the building. In any emergency event even without assistance, the disabled occupants should be able to move freely within a building. In the event that the building is a story building where access is via a lift and stairs, the disabled members should be able to find the lifts where they are located. If need be, special lifts that can be used by the disabled can be installed in the building to provide additional support. Ramps for people with wheelchair assistance. The inclination should be not so steep. Courtesy of Arundhati ramanathan. (2014 ). In buildings with no lifts, an emergency situation can benefit from a well designed and implemented refuge. The refuge would provide the disabled with a position to wait for assistance from the other occupants of the building or security personnel. The refuge area is normally connected by the lower floors via a stairway. However, access to the refuge are within a single floor should be made in such a way that the disabled can get to the refuge via a wheelchair. There should be no steps or stairs on the corridor leading to the refuge are to allow the same access with ease. Ventilation Natural ventilation of a building is done through the windows door or any other opening in the building. This is usually sufficient for low capacity buildings and small residential buildings with few installations that support human life. In deep plan buildings with limited access to supply of fresh air through doors and windows, a ventilation system is needed for ensuring that the air quality remains the same for all the occupants of the building regardless of their location within it. The mechanical ventilation system will ensure that a constant replenishment of fresh air is maintained in the building and toxic or stale air is removed from the building. Since this kind of system normally connects a wide set of rooms in a building, in the event of a fire, the effects of the smoke should be controlled. This can be done by ensuring that the smoke never transfers throughout the system to interfere with other parts of the building. Fire and smoke dampers can be installed to the system to ensure that such hazards are prevented. Escape routes like stairs need to have proper ventilation, that is, free from smoke in the event of a fire. This will enable the occupants to see clearly the routes and make exits to safety without being affected heavily by the smoke. In flats, this can be achieved by setting the staircase at the ends of the buildings for natural ventilation to deal with the effects of smoke in the stairway. Alternatively, if is is impossible to have free flow of air in the stairway, a dedicated ventilation system can be installed for the escape corridors and staircases. References Arundhati ramanathan. (2014). Mapping disabled-friendly buildings and facilities. Http://wwwlivemintcom/. Retrieved 3 December, 2015, from http://www.livemint.com/Specials/3ee825zwXnt14uE3qJIRVI/Mapping-disabledfriendly-buildings-and-facilities.html Flin, R. H. (Ed.). (1997). Decision making under stress: Emerging themes and applications. Gower Technical. Office of the deputy prime minister (2000) approved document B. Onlineversion. /. Retrieved 3 December, 2015. From http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADB_2000.pdf Thenbs.com. (2015). The NBS building standards.Thenbscom. Retrieved 3 December, 2015, from http://www.thenbs.com/buildingregs/ Read More