Means of Warning and Escape in Public Buildings - Term Paper Example

Running Header: Means of warning and Escape routes Student’s Name: Instructor’s Name: Course Code: Date of Submission: Table of Contents Table of Contents 2 1.0 Introduction 3 2.0 Fire alarms and systems 4 2.1 Positioning of fire alarms 5 2.2 Means of escaping 6 3.0 Designing an horizontal escape 10 3.1 The horizontal escape route design 10 3.2 Occupants and number of exits 11 3.3 Determining the exit capacity 13 4.0 Construction of the vertical escapes (stairs) 14 5.0 Conclusion and recommendation 16 References 17 1.0 Introduction The building and construction regulation as amended and approved in 2010 was primarily intended at providing practical guidance on how buildings and different structures should be contracted in curb and mitigate the losses incase there is fire. The approved document is aimed at proving a framework on public and common structures should be done in order to reach higher levels of compliance with the law. Important to note is that nobody is allowed to adopt any method of construction except the one that has been stipulated and provided for in the document. The guidance as provided in the document directly relates to certain regulations that must be met. The buildings have no option but to comply with all the requirements of the law as provided in this document. The requirement states that no single building should be done unless it meets all the requirements (British Standard Institution, 2001). In other words, it must comply with both health and safety conditions. Any building that must be declared to be fit must comply with all the building regulations and that it must have used the correct materials and that it involved the qualified expertise during the construction. Regulation 7 of the document clearly stipulates what aspects the building must comply with before declared fit for both residential and public use. Some of the features that must be demonstrated include the well marked CE bearing must comply with the Construction Product Directive. In general terms, the whole idea of this regulation is to ensure that builds are constructed from the right materials and proper dimensions in order to ensure that the house linings do not support but suppress fire escalation. The primary objective of this report is to critically evaluate the means of warning and escape in public buildings. More emphasis will be put on addressing the Fire alarm and detection systems, Building occupancy and purpose groups and Horizontal and vertical escape route design principles including: Travel distances and Exit widths and Stair provisions (Communities and Local Government, 2006). 2.0 Fire alarms and systems The regulation 2000, which was amended in 2010, provides that all buildings be well equipped in such away they must all have working and functioning fire alarms. The regulation requires that all buildings be installed with smoke and fire alarms in order to allow for easy detection of fire through smoke sensing. This way an earlier warning could be raised in order to take necessary precautions and if possible evacuate the residents earlier enough before any injury is caused. The smoke detection alarm is more emphasized in the residential houses where the populations are high and the risk may be more harmful (Communities and Local Government, 2006). However, in those areas where the fire risks are perceived to be high, the constructors are encouraged to provide more advanced protection and high number of fire detectors. According the recommendations of BS 5839-6: 2004, all residential houses must have fire detectors and response alarms. Smoke as well as heat alarms must all have the mains where the alarms should be communicated to and from. This is according to the conformity regulation BS 5446-1:2000 and BS 544-2: 2003 both which regulates the installation and use of fire alarms and detectors. The first part of the regulation of smoke alarms provides that all buildings must have a standby source of power that could be used to recharge the alarms in case there is a power shortage. This is particularly recommended in order to avoid scenarios where the fire and smoke detectors fail immediately after power goes off. According to BS 5446-1, talks about smoke alarms that are ionizable. This is because different fires alarms respond differently. Some may take time before they can respond while others can be instant. The use of the photo-electric smoke sensors could help detect fire at earlier stages and consequently reduce its effects on residents and property (The Building Research Establishment, 2000). However, according to this regulation, the choice of the fire and alarm detector depends on the risk level, the damage and the situation context. But most important to consider as per this regulation is the type of the detector (British Standard Institution, 2001). This is because some detectors can raise false alarms and thereby causing unnecessary anxiety among the users of the building. The regulation recommends the use of optical detectors since they are less likely to be affected by small and invisible particles and thereby reduce the incidences where false alarms are raised. In addition, these alarms are perceived to be more suitable than the ionizable chambers and therefore they can be very effective for installation in the kitchens (Purkiss, 2007). 2.1 Positioning of fire alarms Position of fire and smoke alarms has also been emphasized by this regulation. The regulation provides a detailed guidance on how structures should be designed in order to allow for strategic installation of fire and smoke alarms. This is according to the BS 5839-6:2004 which regulates the installation and use of firearms in residential houses. This regulation provides that smoke alarms be positioned in such away to sense the occurrence of fire both at sleeping and open spaces (DiNenno et al, 1995). These two areas are prone to outbreaks and the overall loss is likely to be higher is fire cannot be contained earlier enough. Fire and smoke alarms should be well positioned in the kitchen where fire is likely to start first. The regulation also asserts that there should be more than one smoke alarm in every building which is a leaving house. Incase the kitchen is not partitioned from the stairway and the circulation room, there must be a well connected link of the fire and smoke detectors from the kitchen in order to provide reinforcement to any alarm that might be present. In situations where several alarms are installed, they should be linked in such away that the detection of fire or smoke by one of them could lead to detection by all of them and consequently raise an alarm together (British Standard Institution, 2001). To ensure that connection is effective, there is always need to make sure that the manufacturers’ are well ready and understood. The calculations require that the firearms be placed 7.5m from the door towards any leaving room. The ceiling must also be placed in such as away that are at least 300mm from the wall in order to allow for light to penetrate and thereby allow for easier detection of fire and smoke by the alarm (DiNenno et al, 1995). In situations where the units have been designed purposely for wall mounting, it can be allowed as long as they are above the door routes in order to create an open space as per the instructions of the manufacturer. Sensor constructed on a ceiling must be at least 25mm and 600mm just below the ceiling in order to incase they are used for detecting fire. This guidance should be applicable only to those ceilings that are flat and horizontal. This is particularly accepted because it will always be easy to reach the detectors for routine cleaning as recommended by the manufacturer. Important caution that must be followed (British Standard Institution, 2001). 2.2 Means of escaping The regulation as pertains to escaping from fire threatened houses requires that all structures and more especially storey buildings must all have exit doors. In dwelling houses this one is simple to provide because of the size and nature of the house. This document specify a number of provisions that must be followed to ensure that means of escape are provided incase there is fire (CIBSE Guide, 1997). Emergency doors and windows have to be provided. As the building increasingly become big and tall the more complex the process of providing escaping means become. This is because jumping through windows and doors that are higher from the ground become even more dangerous. The document demands that dwelling houses that more than 7.5m from the ground must be provided with other means of escape since it will not be easy to use windows and doors (British Standard Institution, 2001). In ground storey buildings, the regulation requires that all living rooms except the kitchen be open to into the sitting room and the entrance or otherwise a better and suitable escape root be provide. The ground storey buildings must also be provided with a window or a door that can easily be used to access outside. The approved document also recommends that all storey buildings which are more than 4.5m above the ground be provided with windows and doors that can be used to access outside. Perhaps this is because at this height individuals can jump over the window without getting hurt. Direct and accessible stairway should also be provided. This is to allow those individuals who cannot jump away and escape from the fire. According to the regulation, one window is only accepted for two rooms (Stollard and Abrahams, 1995). This is because it can only manage to serve a relative small number of people at one given time. A communication door must also be provided between the two rooms. This is to allow easy access to the window from the two rooms incase a staircase is not to be used. All houses that have a floor that is above 4.5m from the ground should be served by protected stairways. The stairways must be able to give access to escape doors at the ground or directly connect with exit routes. On the other hand, all buildings those have more than one floor that is anchored more than 4.5m from the ground must conform to the following features (Purkiss, 2007). First, the escape route must always be provided from the upper storey as shown in diagram 1 below. The escape route must also be connected with a landing that connects with the alternative escape route. This is to ensure that incase one escape route fails, when is able to access other options that can allow him escape from fire. The reserved stairways which are above 7.5m from the ground must always be separated from the lower escape routes on the lower storeys as shown in diagram 2 below. According to the regulation BS 9251: 2005, all dwelling houses must be fitted with sprinklers. This is to ensure fire mitigation gases and water is reached without much problem. Diagram 1: escape routes from dwelling houses Diagram 2: escape routes from dwelling houses In general, all doors and windows that are provided as escape routes must meet the following requirements: first, the window must always be in access to an open area. The size of the open area must be at least 450 mm in width and 450 mm in height. In addition, it is not necessarily that the window must be a straight through but through an angle (Purkiss, 2007). Second, the windows must allow the people escaping to reach a safe destination without any danger. This greatly depends on the constructor’s judgment that must always adhere to the rules. Based on the courtyard size the constructors are expected to determine how the windows can be placed in order to free escape without any difficult. Third, the inner rooms that have only one escape route to the access areas are discouraged. This is because they real pose a very big danger to the house dwellers because they cannot escape incase there is a fire outbreak (Communities and Local Government 2006). According to the regulation, such inner rooms will only be permitted for the kitchen, the laundry and utility room, the dressing room, the bathroom, shower room and any other room that the constructors and the owners of the house may deem appropriate. This is so important in reducing scenarios where people are trapped in their houses where they can be assisted incase there is fire. Important point to note is that any rooms that can be accessible with the inner room need to meet all the requirements as the inner room. Fifth, additional house rooms such as balconies and top of roofs and that are used as an escape routes, must meet the following requirements: first, the roof must be part of the building from which the escape is being made (The Building Regulations, 2000). Second, the route passing through the roof must lead to the escape routes that lead to the out of the building. Finally, the most and important rule the constructors must adhere to is that the roof used for escaping and that connects to the escape route must resist fire for at least 30 minutes. 3.0 Designing an horizontal escape The general principle that underlies the construction of building is to foster the capability of an individual who has been faced with the fire outbreak to escape without any major injury. This part of the report will critically evaluate the buildings can designed horizontally in order to allow easy escape from fire as provided by the regulation (Purkiss, 2007). 3.1 The horizontal escape route design The most important factor to take into consideration first before constructing an escape route is the number of people who can be found in that room at any given time, the height of the building starting with the ground storey building to a multi-storey building as well as the distance to the adjacent exit route (Stollard and Abrahams, 1995). However, important point to note it’s only the distance to exit route should be limited. Otherwise other exits not necessarily need to be very close. In the multi-storey buildings according the regulation, more than one stair may be required for escape. This may include inactive stairs which might be a very important alternative at times when the fire has occurred. On the other hand, the regulation demands that buildings that are used for various functions and activities different and separate means be provided (DiNenno et al 1995). These kinds of buildings include those that are used for residential, assembly and even recreation activities. The purpose for doing this according the regulation is to ensure smooth escape by building users through well managed and controlled commotion. In order to avoid a situation where people are trapped in the building, there is always need to have several alternative escape routes from a building. However, a single escape can be only be accepted by the regulation if it only satisfies the following conditions: first, if the distance between the floor of the storey and exit destination moves to the same direction. This case should be applied in social places such as small assembly points like bars (BS 5588) (British Standard Institution, 1998). However, this can only happen if there is no single room that carries more than 30 persons at ago. Second, one exit can only be allowed where a storey has less than a capacity of 60 people and where the limits are that they move to one direction (Stollard and Abrahams, 1995). 3.2 Occupants and number of exits The number of occupants in a building will always be used to determine the horizontal exit should be designed (The Building Research Establishment, 2000). In case the number of the occupants is not known in any given building be it a room, one storey or multi-storey building, the capacity can be determined by looking that size of the space that can be used by the occupants. This is demonstrated in the example below. Accommodation type floor space in sq. metre Spectator areas, bars and other refreshment areas 0.3 Assembly hall, bingo halls, clubs, dance halls, hall for pop concert etc 0.5 Concourse, queuing areas and shopping malls 0.7 Committee rooms, common rooms, conference rooms, dining rooms etc 1.0 Exhibition halls, studio for recording, television and film etc 1.5 Skating rink 2.0 Shop sales areas 2.0 Office 6.0 Art gallery, dormitories, factory manufacturing areas, museums and workshops 5.0 Kitchen and library 7.0 Bed-sitter room or study cum bedroom 8.0 Car park space 2 persons in a single parking Storage or warehouse 3.0 As indicated above, it’s evident that to say that the occupants of a room can be determined even when there is no clear number of people who can occupy a certain room (The Building Research Establishment, 2000). Some places such as bars and spectator seem to occupy many people as opposed to the other places such as the manufacturing sites where a single processing unit can take up to around 5.0 square meters. For example, let’s consider a case of a certain manufacturing company based in the Northern of London which wanted to construct a new factory to the west of the city. However, the number of occupants was not but the space for the factory was known and its 1500 meter square. To calculate the number of the occupants, the constructors will take the total space area and divide it with the average number of size which the law has permitted for each occupant which is 5.0 meter square (The Building Regulations, 2000). The number of occupants=total space area available/ the required space for each occupant 1500/5= 300 occupants. On the other the example below is used to calculate the number of escape routes that can be constructed in any one building at any given time. The number of escape routes is directly related to the number of occupants in the room. Consider the table below. Highest number of people Number of escape routes 60 1 600 2 More than 600 3 Based on this table therefore, it is easy to calculate the number of escape routes in a building once the number of occupants. The more the number of people, the more the number of escapes routes that need to be constructed (The Building Research Establishment, 2000). 3.3 Determining the exit capacity In any building it is assumed that the number of escape routes can be more than one. This is to enable the occupants of a room to escape through an alternative route in case one is blocked by fire. However, most important is the number of escapees who can use the route at any given time (BS 9999) (British Standard Institution, 2008). The regulation has provided the following formula for determining the size of the escape route: W= ((N/2.5) + (60S)/80 Whereby: W = the width of the escape route in metres N= Number of persons served by exit at the ground floor S =Width of the stairs in Metres Example The ground floor of a given building in the city is supposed to serve 500 persons and the width of the final exit stair is 2.4 m. required is to determine is the width of the final exit. Final exit = ((500/2.5)+ (2.4 * 60))/80 Width = 2. 150 metres The wider exit is to allow more people to escape from the building at any one given time (Stollard and Abrahams, 1995). 4.0 Construction of the vertical escapes (stairs) In any storey building, the most important factor during construction as per this regulation is the number of designed and preserved escape stairs. The number vertical escape stairs required at any given time depends on a number of factors which have already been discussed in the construction of horizontal escape routes above. The determination of the escape route width is great importance as earlier reported in the horizontal escape construction (The Building Research Establishment, 2000) (BR187). The always the width of the stairs should not be less than the required width, must comply minimum width requirements of the regulation and no any case the width should exceed 1400 mm if the vertical distance is more than 30 m. the width should be uniform all the way. The BS 5588-7: 1997, regulates the construction of simultaneous vertical escape routes. In case where simultaneous evacuation is to be, the following conditions must be met: all stairs must serve the basements, all stairs must serve all parts of the building and that all residential, recreation and assembly buildings must have simultaneous escape routes. The capacity of the stairs, which are 1100mm or more and that are used for simultaneous evacuation can be used using the following formula: P = 200 W + 50(W-0.3)(N-1), or W= P+15n-15/150+50n In this case: P is the number of persons who can be served by the stair W refers to the stair width N is the number of storeys that can be served by the stair Example 1: A given office is placed at more than 18 metres high. The number of people who can be served is 600 The number of storeys is 11 Provided the formula, the width will be calculated as follows: 600 = 200W + 50 (W- 0.3) (11-1) 600 = 200 W + (50W – 15) (10) 600 = 200 W + 500 W – 150 750 = 700 W W = 1070mm 5.0 Conclusion and recommendation Based on the ammended and approved Building Regulation of 2010, it is evident to say that the major of this document is to harmonze all the procedures and policies that guide the construction of the dwelling houses. Particularly this is to ensure that appropriate measures are taken to counter incidences of fire and related losses. The document plays a very major role in creating ways that can be used to warn and assist people to escape whenever there is a fire outbreak (British Standard Institution, 2008). However, to make sure that this article is well implemented, the following two recommendations must be followed: 1. There is need to organize for programmes which can be used to educate the general and create awareness among the people and at the same time help them appreciate the role of the regulation. 2. There is need to clealy state the penalty one is likely to face incase he objects to the policies and regulations stipulated in this document. This is to make sure that the public is adhering to the regulation. References British Standard Institution 1998, BS 5588, Fire precautions in the design, construction and use of buildings, London, British Standard Institution. British Standard Institution 2001, BS 7974, Application of fire safety engineering principles to the design of buildings – code of practice, London, British Standard Institution. British Standard Institution 2008, BS 9999, Code of practice for fire safety in the design, management and use of buildings, London, British Standard Institution. CIBSE Guide 1997, E – Fire engineering, The Chartered Institution of Building Services Engineerings, London. Communities and Local Government 2006, Building Regulations 2000; Fire safety, Approved Document B-Volume 1; Dwelling Houses, Viewed 6 May 2011, from http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADB1_2006.pdf DiNenno, P. J. et al 1995, SFPE Handbook of fire protection engineering 2nd edn., London, National Fire Protection Association, Society of Fire Protection Engineers.  Purkiss, J 2007, Fire Safety Engineering Design of Structures, Elsevier. Stollard, P and Abrahams, J 1995, Fire from First Principles, A design guide to building fire safety, 2nd edn, E & FN Spon. The Building Research Establishment 2000, BR187, External fire spread: building separation and boundary distances, The Building Research Establishment, Garston. The Building Regulations 2000, Approved Document B – Fire Safety, London, Her Majesty’s Stationary Office. Read More