Fire Engineering Safety Design - Term Paper Example

Heading: Fire Engineering Safety Design Your name: Course name: Professors’ name: Date Introduction There are several cases of fire accidents and deaths in the United Kingdom. It is essential that the building designers consider all the guidelines and codes provided so as to enhance fire safety among the people. This report is based on an analysis of the functional requirement B1 of the UK regulation on fire safety. This requirement involves the means of warning and escape in case of a fire outbreak in a building. Here, different ways in which the designers can meet the requirements through the use of standard codes and guidance. Moreover, some of the key issues that the report focuses on include building occupancy; purpose groups, vertical and horizontal escape route designs principles that include stair provisions and exit widths and travel distance, and fire alarms and detection systems. Functional Requirement B1 Requirement B1 outlines that any building constructed should be designed in a such a way that it gives room for the suitable provisions for timely warning of fire, and suitable means of escape in case of fire outbreak in the building to safety places outside the building, which can be used effectively and safely at all times (Knight 2007, pp. 42-70). Performance Requirement B1 can be met provided that there are routes of adequate capacity and number that are appropriately located so as to enable people escape to safe place in case of a fire outbreak. A building is also said to meet the functional requirement B1 if the available routes are effectively protected from the negative consequences of fire where essential. Additionally, B1 requirement is achieved by ensuring that the escape routes in a building are sufficiently lit so as to ease people’s movement. Moreover, the building should be designed in such a way that its exits are appropriately designed (Binggeli 2010, pp. 332-340). Most significantly, the building should be fixed with suitable facilities that either reduce the ingress of smoke, or limit fire and eliminate smoke. Furthermore, the building ought to be designed to an extent that is dependent on the purpose, height ad size of the building. The requirement B1 is also met if there is adequate means of issuing an early warning of danger to all individuals in the building. Knight (2007, pp. 42-70) says that it is vital that any emergency case, such as, fire outbreak in building is handled appropriately so as to minimize possible accidents and deaths. This implies that the people should be in a position to escape and reach safe areas as quick as possible. This calls for the design of enough exit doors and routes that let people to the last exit, and considerable away from the burning building. Cote (2003, pp. 50-60) says that the design of the building’s escape routes largely depend on its layout and complexity; its size, occupants’ mobility and the number of floors it has. The design of the exit routes should reflect the routine circulation patterns on the building. This is influential in avoiding the provision of optional escape routes that are only suitable in emergency cases. Besides, this will boost the occupants’ familiarity with the exits; thus reduced anxiety in case of emergency, especially with the sounding of alarms. Further, Knight (2007, pp. 42-70) asserts that the requirement B1 is useful stressing that design of escape routes and other fire safety equipment like alarm systems, must be based on risk assessment to building occupants. This assessment should consider purpose of the building, nature of the building’s structure, materials kept or processes taking place within the building, possible fire sources, possible spread of fire in the building, and the proposed fire safety management standards. It is worth noting that fire does not always start in more than one area, but that it starts from one area and spreads to other places through circulations. Some of the things that are first burned include furnishings and other objects that are not controlled by rules. There are limited chances that fire will start on corridors, stairways or lobbies, but mostly at the building’s structure. The most dangerous thing about fire at its first stages is the noxious gases and smoke, but not flame. This is because they lead to any casualties and can obstruct occupants’ way to exits and escape routes. Therefore, there is a need for provision of suitable arrangements that will restrict fast spread of fumes and smoke in the building (Knight 2007, pp. 42-70). In addition, the Requirement B1 is instrumental in the provision of primary principles for designing an escape means. One of the principles is the necessity for optional escape means from most circumstances. Besides, Binggeli (2010, pp. 332-340) asserts that there should be a possibility of reaching a safe place in a considerable travel distance, in case people cannot get to out of the building. This can be categorized into two; protected and unprotected escape routes. Another significance of the requirement B1 is the fact that it outlines some of the prohibited means of escaping from a burning building. Some of these include throw-out ladders, portable ladders, lifts, manipulative appliances and apparatus, such as chutes and fold-down ladder; and spiral or helical stairs. Although escalators are likely to be used by people running away from a burning building, they are not considered among safe exit means. Nevertheless, the requirement allows the use of mechanized walkways provided that their capacity is evaluated. In some of instances, Knight (2007, pp. 42-70) argues that certain exit points are barred by smoke, fire or fumes. Here, it is essential that an alternative escape route is available for the occupants to get out of the building. The requirement significantly advises on looking for other alternatives to safety places away from the building. The requirement also brings out two types of escape routes that include protected and unprotected routes. To start with, unprotected escape route involves a section that a person has to cross before getting to the safety of the last exit, or the protected safety like a protected stairway or corridor. Unprotected escape routes must be restricted in extent so that individuals do not travel long distances while exposed to danger of smoke and fire. Still with the protected horizontal routes, the distance to the last exit point should be reduced because the structure does not protect people indefinitely. On the other hand, Binggeli (2010, pp. 332-340) says that protected escape routes are created to offer practically fire sterile locations which enable people safely get out of the building. In the protected route, an individual is assured of safety from immediate risk of smoke and fire. These areas enable people escaping to get out of the burning building at their own speed. This is achievable by ensuring that the areas are protected from smoke, fire, and fumes. This is also possible by using fire-resisting materials and structures in the building. Additionally, the importance of the requirement B1 is also demonstrated its focus on security issues during a fire outbreak. There is need for rapid and easy evacuation of building, and this may happen against security interests. Therefore, it is imperative that all the measures that may obstruct evacuation activities and rescue efforts be limited in such a situation. Moreover, any possible conflicts should be discovered at the design stage and eliminated before completion. Here, it is significant to consult police and architectural liaison officers so as to advice on the way forward (Cote 2003, pp. 50-60). Building occupancy, purpose groups The occupancy groups involved in this report include assembly group, business group, education group, institutional group, mercantile group, storage group, utility and miscellaneous group (International Building Code, 2006, pp. 23-25). To start with, the Assembly group A entails the use of a structure and building, or a section thereof, for collecting together of people together for reasons, such a, social, civil, or religious functions, drink or food consumption, recreation, or awaiting transporting. Business group B entails the use of structure or building, or a section thereof, for professional, office, or service-type transaction, and records and accounts. Moreover, Education group E includes, among others, the use of structure and building, or a section thereof, by at least at any moment for educational reasons through 12th grade. Institution group I concerns the structures and buildings occupied by people of any age who attain custodial care for at most a day by individual other than guardians or parents, relatives by marriage, blood, or adoption. Additionally, Binggeli (2010, pp. 332-340) notes that a Mercantile group M includes structures or buildings or a section thereof, for demonstration and sale of goods, and entails wares, stock of goods, merchandise incidental these reasons and accessible to the public. Mercantile occupancies will include drug stores, department stores, markets, and sales room. In addition, Storage group S includes, but unlimited to, structure or building, or a section thereof, for storage that is not categorized as a risky occupancy. Building regulations and codes also has another Utility and Miscellaneous group U (Binggeli 2010, pp. 332-340). This entails structures and buildings of an accessory miscellaneous structures and accessory character not categorized in any particular occupancy will be constructed, fixed and maintained to conform to the code’s requirements. Lastly, there is a Residential group R entails the use of structure or building, or a section thereof, for sleeping accommodations when uncategorized as an institution group I (International Building Code, 2006, pp. 23-25). Fire alarm and fire detection systems According to the requirement B1, all buildings must have arrangements necessary for raising alarms in case of fire. In places with a single storey with at most 160 occupants, alarm can be raised by the use of simple systems (Knight 2007, pp. 42-70). For example, manually operated sounders, such as, hand bells and rotary gongs can be used. Nonetheless, it is critical that the kind of warning issued in a building is heard and understood by all occupants in the building, including such areas as toilets. It is crucial that all buildings are fitted with electrical fire warning systems. According to the BS 5839-1, there are three classes of the warning system that include ‘M’ for manual systems, ‘P’ for protection of property, and ‘L’ for life protection. Fire alarm can be employed as a lesson change in schools to demonstrate the beginning or the end of prearranged periods (Association of Fire Chiefs International 2011, pp.151-160). Therefore, fire warning by use of bells and gongs may not be the appropriate ways of alarms in such places. Generally, class M system can meet the building regulations and other rules for institutions like schools. Nevertheless, there are situations where class L fire sensing system is applicable. Class L can further be divided into L1, which entails systems fixed through protected buildings; L2 that involves systems fitted on certain parts of the protected building; L4 that refers to systems fixed in the parts of escape routes and consist of circulation spaces and circulation areas, such as, stairways and corridors; and L5 are systems in which location of detectors and protected areas are designed to meet particular fire security objective other than L1, L2, L3, and L4 system categories (Knight 2007, pp. 42-70). Manual call points should also observe the building fire safety regulations. these installations should comply with the BS 5839-2:1983, or BS EN 54-11:200’S Type A. Type B call points must only be applied with the Building Control Body’s approval. To begin with, Type A or direct operation involves a call pint that has an automatic change to alarm in case of a broken or displace frangible element. Secondly, Type B call point entails a manual change of an alarm in case of a displaced or broken frangible element (Association of Fire Chiefs International 2011, pp, 151-160). Further, this requirement points out the importance of fixing the call points that are not susceptible to malicious operation. This is attainable by locating them in open view of the workers or staff of an institution involved. It also suggests that designers should install voice alarm systems so that occupants are given both verbal instructions and audible signals. Most importantly, the fire safety alarms should be different from other signals by carrying explicit verbal instructions that are comprehensible to all occupants. In case a voice alarm is to be installed in a building, it should strictly comply with the BS 5839-8:1998 Code of practice for the voice alarm system’s designing, fixing and servicing. What is more, Association of Fire Chiefs International (2011, pp, 151-160) asserts that installation of alarm systems in a building should also consider occupants that have hearing impairment. This means that an appropriate warning method, such as, audible and visual fire signal ought to be fixed in institutions that are most likely to have hearing impairment occupants or staff. In most instances, a vibrating paging system is suitable, unlike fixed beacons. It is also an appropriate method of warning people with various disabilities. According to clause 18 of BS 5839-1:2002, there is guidance on the selection and design of fire alarm that have hearing impairment (Knight 2007, pp. 42-70). Functional Requirement B1 also emphasizes on the design and fitting of warning systems. According to this requirement, it is vital that fire detection and warning systems are properly designed, fixed and maintained. There is a need for provision of a fitting and commissioning certificate whenever an alarm system is installed. This is to ensure that high quality, reliable and safe systems are installed in a building. Besides, it is crucial that alarm systems used in institutions like schools are standardized. Nevertheless, there is a provision that such systems are self contained in distinct buildings. According to Cote (2003, pp. 50-60), it is also crucial that the line between fire alarm system and fire detection, and other systems that comply with the Building Regulations is made to attain a high reliability degree. There ought to be specific care if the interface is operated through another system like an access control mechanism. Where a part of BS 7273 relates to other mechanisms’ systems, the recommendations of the standards must be followed. In terms of property protection, there ought to be arrangements for warning and rescue in order to reduce the time between fire start and fire-fighters’ arrival. These arrangements are aimed at reducing risks to people responsible for calling the service. Category P should be employed if the institution is not always occupied, and the type P systems are sub-categorized into P1 systems fixed all over the protected building and P2 is fitted in certain areas of the protected building. In order to achieve the objectives of protecting property, there is a need for integration of automatic alarm transmission to the rescue and fire service (Association of Fire Chiefs International 2011, pp, 151-160). Design of horizontal escape according to Knight (2007, pp. 42-70), the key principle in designing escape facilities in a building is that the occupants escaping can easily get out of the building within the least time possible. Requirement B1 says that dead ends should not be included in new buildings. Nevertheless, under some conditions, dead ends may be accepted as offering considerable safety. These conditions are dependent on the fire risk, number of people that can be accommodated by dead end, and size of the dead end. In designing a building, Cote (2003, pp. 50-60) maintains that there are a number of exits and escape routes that should be considered. Nevertheless, this is reliant on the storey or tier, number of occupants in the building, and the borders on travel distance to the immediate exits. In multi-storey buildings, more than one stairway should be constructed. However, Morawski (2007, pp. 34-40) says that this does mean that areas will not be in dead ends, as long as one of the accessible stairways is unusable. Occupants can be saved from getting trapped by smoke or fire by fixing an alternative escape route or exit in a building. In as much as dead ends are not allowed in new buildings, there are situations that allow for them. This is acceptable for floor parts that from which exits are reachable within the travel distance limit for traveling in a single direction. This is possible as long as no one room in such a circumstance has over 60 people occupant capacity (Knight 2007, pp. 42-70). It is also acceptable in a storey with occupant capacity of at most 60 people where the borders on travel in a single direction only are met. Occupant capacity is calculated as follows: For every exit from a room, regardless of its size, the maximum occupancy is 60 people. For two exits depending on the size, the maximum occupancy is 600 persons. For example, two double exits enter one corridor from which there is a single double door to last the exit. The exit width will be that of the one double door not the two doubles. For 750mm=100 persons; 850mm=110 persons; 1050mm=220 persons Upon getting over 1050mm wide, the exit width should be divided by 5mm, and let a single person for every 5mm. For 1450 mm exit width, the number of people that are allowed to get out is achieved by dividing the width by 5. That is 1450/5=290 people. In case of a 100-square-foot room with a capacity of 2.5 feet per person, it will have an occupant load of: 100 square feet/2.5-foot person = 40 occupants. In terms of access to control mechanism, requirement B1 maintains that that measure should be incorporated in the in the design of every building so as to limit its access must not have adverse effects on the provision of fire safety. Even though it is, at times, necessary to have escape routes outside usual business time, the mechanisms left in place must be adequate to allow safe evacuation of people in the building (Morawski 2007, pp. 34-40). Limits on travel distance With respect to limits on travel distance, there are several benefits associated with limiting travel distance to place of safety. It allows safety without too much exposure to smoke as well as reducing complexity and size of enclosure. Besides, it increases the possibility of making the exits visible in the event of fire outbreak. This also reduces the probability that the fire will not be detected or enlarges before the alarm, as well as the possibility firing occurring between exits and occupants (Knight 2007, pp. 42-70). Width of exits and escape routes This largely depends on number or persons that want to use it. According to the regulations, corridors that lead to more two rooms should have an explicit width, at least 1.8m, while smaller corridors should have widths of at least 1200mm, as compliance to Approved Document M Access to and Use of buildings. In case of dead ends, the minimum approved width of corridor is 1600mm, unless one room of less than 60 persons that use a corridor of at most 4.5m length, and at most 1.05m width. The minimum width 1200mm is enough to be used as an escape route for over 250 people. In case there are more persons, the width should be increased by 75mm for every 15 extra people (Cote 2003, pp. 50-60). Notably, the total width of the exits and escape routes must not be less than what is needed to serve large numbers of persons to use them. The number of persons that at least available exits, after discounting, can serve is arrived by adding maximum number of people that can be served by every exit width. For example, for three exits of 850mm width, the number of persons will be 3x11=330 people, and not the 510 people that single exit can serve. In a case a ground floor storey exit shares the last exit with a stair via a ground floor lobby, the last exit’s width of last exit must be adequate to allow greatest evacuation flow rate equivalent to or greater than from stair and storey exits. The appropriate to use is as follows: W= ((N/2.5) + (60s))/80 Where: W= final exit’s width in meters N=number of people accommodated by ground floor storey exit S= stair width in meters For instance: If there is an assumption that one stair is unavailable because of smoke-logging, the 1200 people in the building will need to use the remaining three stairs, that is, 400 people per stair. Substituting n=3 and p=400 into the formula for w imply: w=400 + 15x3-15/150 + 50x3= 430/300= 1.43 In a situation in which two or more stairs are provided, there is a possibility that one of them will be inaccessible because of smoke or fire. This calls for discounting of each stairway so as to ensure that the remaining stairs can cope with the demand. Nevertheless, discounting is dispensable if they are sheltered by a pressurization smoke control mechanism as per BS 5588; part 4, or if they are accessed through a sheltered lobby at every floor level (Morawski 2007, pp. 34-40). In a multi-storey buildings in which occupants exceed 220, it will be vital to consider evacuation mode and employ other methods to compute stair widths. In a case in which all occupants would be removed from the building (simultaneous), the design should allow all stairs to serve basements; stairs serve buildings that have open spatial plan; and that all stairways serve assembly, residential and recreational buildings (Morawski 2007, pp. 34-40). To calculate capacities of stair widths of at least 1100mm, this formula can be used: P=200w + 50(w-0.3) (n – 1) Where: p= number of people that can be served by the stair w=width of stair in meters n= number of storeys in a building Therefore, if p= 400, and there are n =5, what is w? Substituting p with 400 and n with 5, w will be: 400=200w + 50(w-0.3) (5-1) 400=200w + 50 (w-0.3) (4) 400=200w + 50w-15 (4) 400=200w + 200w-60 460=400w w=460/400 w=46/40 w=1.15 meters. Conclusion Requirement B1 of the DB, BS999, BS7974 codes and regulations brings out imperative issues that should be considered in the warning and escape from fire. Some of them include limits on travel distance, widths of exits and escape routes, fire safety alarms, and occupancy groups and purposes. Design of horizontal escape routes is also significant in the appropriate design of a building so as to maintain safety that can be caused by fire outbreaks. Moreover, there requirement emphasizes the significance of alternative exit and escape routes in a building in the reduction of adverse effects of fire in a building. Moreover, the issue of protected and unprotected exits and stairways in designing building is also emphasized. Therefore, any fire safety design made on a building should meet the aforementioned codes and regulations. References Association of Fire Chiefs International 2011, Fire Inspector, Jones & Bartlett Learning, Burlington, MA. pp. 151-160 Binggeli, C 2010, Building Systems for Interior Designers, John Wiley & Sons, Chichester. pp. 332-340. Cote, A 2003, Operation of Fire Protection Systems, National Fire Protection Association, Quincy. pp. 50-60. International Building Code 2006, Use and Occupancy Classification. pp. 24- 25. http://webtools.delmarlearning.com/sample_chapters/1580012515_Ch3.pdf Knight, J 2007, Building Bulletin 100; Design for fire safety in schools. Department of Children, Schools and Families. pp. 42-70. https://www.n- somerset.gov.uk/NR/rdonlyres/3977C675-4004-402B-B7A2- 96072A7B2C89/0/Section10_3678_Buildingbulletin00fireaw.pdf Morawski, E 2007, Fire alarm systems handbook: a guide to all types of fire alarms for property managers, 2007, E. E. Morawski, California. pp. 34-40. . Read More