Fire Resistance Design - Assignment Example

University of Central Lancashire School of Engineering FV1202DesignAssignment Brief PART A – Answer ALL 5 questions – total marks for this section is 50%. Include appropriate references. 1. Discuss the terms “fire resistance testing” and “reaction to fire Testing”. Fire resistance testing is a procedure followed to accurately determine the ability of the materials used for building construction, the various products used in building as well as the various building components such as floors, ceiling and walls to withstand various adverse environmental conditions such as pressure and temperature while maintaining their specific functions such as load bearing and/or fire separation property. Fire resistance testing can also refer to the process of determining the building material’s ability to resist and/or prevent fire passage from one area to another. The main products that are tested for resistance include; walls( including both the bearing and non- bearing ones), hardware, doors, floor, ceiling, furniture, house finishes, partitions in rooms, door frames, beams, windows, panels and any other component that will be considered vital in fire resistance in the building. The importance of fire resistance testing cannot be underrated because it helps to determine the behaviour of the various building elements when in direct contact with heat and various pressure conditions which are always experienced when fire is fully developed (Gypsum Association 1977). The duration of the various building components to contain fire, while maintaining the integrity of the structural properties is noted. It indicates the components’ fire resistance ability (Gypsum Association 1977). Reaction to fire testing is a process that determines the contribution of the materials used in buildings to fire development, and ultimately fire spread specifically in the initial stages of fire, when the main goal is the evacuation of the occupants. The material behaviour to fire will (i.e. contribution to fire development, ignition easiness, produced energy and rate of the spread of flame) influence to a larger extent, the ease with which the occupants of a building will escape in case of a fire incident. To accurately determine the reaction to fire testing of a material various tests can be performed on the material such as; the spread of flame, the ignition, toxicity and smoke generation (Gypsum Association 1977). 2. Discuss the functional requirements (B1 to B5) of Approved Document B. The approved document contains the following main sections; B1-means of warning and escape B2-Internal fire spread (linings) B3- Internal fire spread (structure) B4-External fire spread B5-Access and facilities for the fire service These sections have specific functional requirements as discussed below; B1-means of warning and escape This section majorly ensures that the occupants get a warning of a fire outbreak on time and that safety of the occupants during escape is catered for. This therefore requires that different devices to give warning to the occupants are installed in buildings and that well defined routes of escape from the building to a safer outer place should be provided (Gypsum Association 1977). The outer place should be safe at all times. The functional requirement of this section includes: The escape routes provided should be sufficient in both number and capacity. In addition, the escape routes should also be located suitably to ensure that persons escape to the place of safety conveniently. The escape routes where necessary should be protected from the fire effects sufficiently. It is also important to ensure that the escape routes are well lit to ensure that the occupants find their way out of the building easily. To ensure easy access hence avoiding confusion during escape, the escape route should be suitably signed and proper escape direction provided. To ensure safety of the occupants during escape, the escape route should have appropriate facilities that will ensure the smoke ingress to the escape route is limited. In addition, the fire should be restricted to the escape route and smoke should also be effectively removed from the escape route. The escape route provided should be large enough to accommodate all the occupants and allow safe escape within a very short time. To ensure that the occupants escape from the building at the right time, effective warning on the outbreak of fire should be provided by installing necessary equipment to give early warning to the occupants. B2-Internal fire spread (linings) This section is concerned with the effective inhibition of fire spread over the internal lining of the building. This can be achieved in two main ways; The internal linings should be able to resist flame spread over their surfaces adequately If ignited, the heat release rate or the fire growth rate of the internal lining should be reasonable. The functional requirement of this section includes: Flame spread over the building internal lining should be restricted ensuring that they have low rates of surface spread of flames. The building internal lining should have low rates of heat release (Gypsum Association 1977). This will be helpful in reducing the contribution of the building fabric to fire growth. This can be achieved by making sure that the internal linings have a high resistance to ignition and a reasonable fire growth rate. B3- Internal fire spread (structure) This is important in ensuring; the building stability in a fire event, sufficient fire separation degree within and between adjoining buildings, automatic suppression to fire is provided where necessary and unseen fire and smoke spread in concealed building spaces is inhibited. To achieve the aforementioned properties, the following conditions should be observed: The design and construction of the building should be such that, the stability of the building will be maintained for a reasonable period of time in the event of fire. In buildings where a common wall exists between two or more buildings, it is important to design and construct the wall so as to resist fire spread between those buildings adequately. When interested to inhibit fire spread within the building, the building sub-division should be constructed with fire-resisting materials and appropriate automated fire suppression systems should be installed. The design and construction of the building should also ensure that the unseen fire and smoke spread in hidden spaces in its structure and fabric is inhibited. So as to achieve the above conditions are met, the following important factors should be considered; The loading bearing structural elements of the building should be capable of adequately withstanding the fire effects for an appropriate period without stability loss. The building should be sub-divided into compartments by fire resisting elements of construction. Adequate protection of any openings in the fire-separating elements so as to maintain the elemental integrity. Hidden voids should be should be sealed and sub-divided in the construction so as to inhibit the unseen fire spread which will consequently lead to the reduction of structural failure risk. B4-External fire spread The major goal of this section is to ensure that adequate resistance to the fire spread is accorded to the external walls and roof over the external envelope and restricting fire spread from one building to another. So as to achieve the aforementioned functions, the following factors need to be considered; The external walls should be constructed so that the ignition risk from the external source and fire spread over their surfaces, is sufficiently restricted ensuring that they have low rates of heat release. The unprotected area amount in the building side should be restricted so as to limit thermal radiation passing through the wall. The roof should be constructed so that the flame spread risk and/or penetration of fire from an external source of fire is restricted. B5-Access and facilities for the fire service This last section is supposed to ensure that access for fire appliances to buildings is satisfactory and adequate facilities for fire fighting to save lives are provided. In order to meet the required goals, the factors below are considered; There should be enough access to external parts of the building so as to ensure the fire appliances are brought near for effective use. There should be sufficient access of the fire-fighters into and within the building to ensure that all people within the building are saved. The building should be provided with adequate internal fire mains and other facilities to help the fire-fighters in their work. The building should be provided with adequate means for heat and smoke venting from a fire in the basement. 3. Discuss the term means of escape and the process of escape. Means of escape: The key principle on the means of escape is that the available time for escape should be longer than the actual time that will be required for the escape. This therefore ensures that the occupants in the building are able to escape to the place of safety safely. The means of escape adequacy and effectiveness depend on a number of factors such as; the building parameters including the building size, design layout, the number of occupants and ability to easily escape unassisted, the exit dimensions, the purpose of the building and many other factors. It is therefore important that in any building, the means of escape should be provided clearly so that the occupants can easily evacuate the premises without any casualties reported. The process of escape includes the following defined stages; Escape from the source of fire or any other room within the building from which the fire originates, Escape to a protected area offering refuge from the source of fire through a well defined circulation route. Escape to the ground level from a specific floor of fire origin Escape to a ground away from the building. It is important therefore, that every building floor plan should accurately determine the shortest escape routes to a place of safety in case of fire. To alert the people to evacuate the building an evacuation mechanism should be installed such as the use of the emergency alarm. The sizes of the exit doors as well as the escape routes, specifically the width will dictate the number of people and that will safely escape at a given time through the escape route. 4. Explain the term “travel distance”. Travel distance refers to the distance that can be travelled by a person from a point within a building’s floor area to a well-defined exit. It mostly refers to the distance measured horizontally, for example, along a floor centre line. The distance from the most remote part of the building to a given point of safety is then referred to as the travel distance. The place of safety referred to in this case may include; a well-protected exit, the point where the first tread of the exit staircase is found and a room with a fire-protected wall (Ignall, Rider, & Urbach 1978). To determine the travel distance accurately, the type of building has to be considered i.e. if the building is an office, plant room etc. This is because, each building results to a different travel distance as in ADB table 3. The travel distances provided in the design of the building should be more than the recommended distance in the ADB table. 5. Discuss the importance of space separation between buildings. It is always important to have a definite space between any two buildings in the same place. From various research and experiences, most cities and big towns have experienced frequent fires which result to loss of life and property since the fire control in those place becomes very poor. This is as a result of; very small distances between buildings making the access of the building on fire very difficult and failure to adhere to the building regulations (Ignall, Rider, & Urbach 1978). Adequate space between buildings therefore makes it easy to control any fire outbreak since the building on fire can be easily accessed and the fire controlled on time. In addition, the separation distance ensures that fire spread is limited to the adjacent buildings. This will control, the rate of fire spread adequately thud reducing the cost of putting out the fire in a given location. 1. What is the maximum recommended compartment size for each of the following cases: a) A single storey shop with sprinkler protection Reference Description Height of floor of top storey above ground level(m) Floor area(m2) ADB TABLE 12 Shops sprinklered No limit No limit b) A single storey industrial unit (1 mark) Reference Description Height of floor of top storey above ground level(m) Floor area(m2) ADB TABLE 12 Industrial not sprinklered Not more than 18 More than 18 No limit N/A 2. What is the maximum size of an opening (unprotected area) that can be discounted when considering space separation between buildings? Reference Description Dimension restriction (m) Diagram 44 Unprotected areas that can be disregarded in assessing the separation distance from the boundary 4 3. What is the minimum recommended fire resistance periods for the following structures: a) A 35m high sprinkler protected residential building Reference Description Height of floor of top storey above ground level(m) Minimum period of fire resistance in minutes ADB TABLE A2 Residential building sprinklered More than 30 120 b) A ten storey shop with sprinkler protection Reference Description Height of floor of top storey above ground level(m) Minimum period of fire resistance in minutes ADB TABLE A2 Shop sprinklered More than 30 120 4. In each of the following cases state whether a fire fighting shaft is recommended and if so whether or not a fire fighting lift is also required: a) An office building with a top occupied floor of 250m2 located at 19m above fire service vehicle access level A fire fighting shaft is required since the building height is to high. b) A four storey assembly building with a top storey of 1400m2 located 10m above fire service vehicle access level A fire fighting shaft is not required but a fire fighting lift may be necessary 5. What purpose groups would be appropriate for the following premises? a) A hospital b) A hotel c) A manufacturing factory d) A swimming pool building. reference use of premises Title Purpose group ADB TABLE D1 A hospital Residential (institutional) 2(a) ADB TABLE D1 A hotel Residential (institutional) other 2(b) ADB TABLE D1 A manufacturing factory Industrial 6 ADB TABLE D1 A swimming pool building. Assembly and recreation 5 6. According to Table 2 of ADB, what are the recommended travel distance limitations (single direction & more than one direction) for the following: a) A normal hazard storage facility b) A place of special fire hazard c) The bedroom of an apartment d) A lecture theatre with fixed seating in rows e) Shop floor f) A residential care home (3 marks) Reference Use of the premises or part of the premises Description One direction only(m) More than one direction (m) ADB TABLE 2 Storage and other non-residential Normal hazard 25 45 ADB TABLE 2 Place of special fire hazard 9 18 ADB TABLE 2 Bedroom of an apartment Other residential (in bedrooms) 9 18 ADB TABLE 2 A lecture theatre with fixed seating in rows Assembly (areas with seating in rows) 15 32 ADB TABLE 2 Shop floor Shop and commercial 18 45 ADB TABLE 2 A residential care home Other residential (elsewhere) 18 45 7. According to Table 3 of ADB, what is the recommended minimum number of escape routes from a storey with: a) 50 people b) 400 people c) 550 people d) 605 people (2 marks) Reference Maximum number of persons Number of persons Minimum number of escape routes/exits ADB TABLE 3 60 50 1 ADB TABLE 3 600 400 2 ADB TABLE 3 600 550 2 ADB TABLE 3 More than 600 605 3 8. According to Table 4 of ADB, what is the minimum exit width required to accommodate: a) 109 people b) 218 people c) 10 people d) 500 people (2 marks) Reference Maximum number of persons Number of persons Minimum width in (mm) ADB TABLE 4 110 109 850 ADB TABLE 4 220 218 1050 ADB TABLE 4 60 10 750 ADB TABLE 4 More than 220 500 2,500 9. A building with four above ground floors is served by two escape stairs without lobby protection. Using Table 7 of ADB, what is the minimum width of the escape stairs if each floor accommodates: a) 75 persons b) 130 persons Reference Maximum number of persons served by stair of width 1000mm Maximum number of persons served by stair of width 1100mm Actual number of persons served by stair Stair width required (mm) by interpolation ADB TABLE 7 270 340 Reference Maximum number of persons served by stair of width 1600 mm Maximum number of persons served by stair of width 1700 mm Actual number of persons served by stair Stair width required (mm) by interpolation ADB TABLE 7 515 550 10. A building with five above ground floors is served by three escape stairs with lobby protection. Using Table 7 of ADB, what is the minimum width of the escape stairs if each floor accommodates: a) 155 persons b) 230 persons Reference Maximum number of persons served by stair of width 1000 mm Maximum number of persons served by stair of width 1100 mm Actual number of persons served by stair Stair width required (mm) ADB TABLE 7 310 380 310 Reference Maximum number of persons served by stair of width 1100 mm Maximum number of persons served by stair of width 1200 mm Actual number of persons served by stair Stair width required (mm) by interpolation ADB TABLE 7 380 420 11. Assuming 100 occupants from the ground floor accommodation also exit through the ground floor of the stair enclosures for Questions 9 and 10, how wide do the final exits need to be? (i.e. a merging flow – diagram 15 and associated equation). The formula used in calculating the final exit using the merging flows at final exit as given below; as provided in figure 15 in the ADB document; Since the number of people (N) entering the lobby from the ground floor exceeds 60, i.e. 100 persons are available. The distance from the foot of the stair, or the storey exit , to the final exit should be a minimum of 2m (ADB document note) Given; Part 1 Then; Part 2; Therefore; 12. According to Table C1, what floor space factors would be appropriate in the following areas? a) An office b) A bar within 2m of serving point c) A shop sales area d) A restaurant Reference Type of accommodation Floor space factor m2/person ADB TABLE C1 Office 6.0 ADB TABLE C1 A bar within 2m of serving point 0.3 ADB TABLE C1 A shop sales area 2.0 ADB TABLE C1 A restaurant 1.0 13. For a square room, 40m by 40m, calculate the number of occupants using the floor space factors obtained in Question 12. In each case what is the minimum number of exits required and how wide should each exit be as a minimum. Given; For an office; Minimum no. of exits required; Width of exit for the office; When both exits are functioning as required, each should accommodate When considering the worst case scenario in which one of the exits may be closed an only one may be functioning properly, then the exits should be designed to accommodate 267 persons. In which case, A bar within 2m of serving point; Minimum no. of exits required; Width of exit for the bar; When all exits are functioning as required, each should accommodate ; A shop sales area; Minimum no. of exits required; Width of exit for the shop sales area; When all exits are functioning as required, each should accommodate ; A restaurant; Minimum no. of exits required; Width of exit for the shop sales area; When all exits are functioning as required, each should accommodate ; 14. What is meant by the following terms: a) Life safety: this refers to a process whereby, the people’s lives are considered in case of a fire safety exercise b) Property protection: this refers to a process whereby all the properties in a building are kept safe and free from destruction as a result of fire. c) Fire resistance: ability of a material to withstand high temperature as a result of fire without compromising its functionality or properties. d) Cavity barrier; this refers to the separation between concealed spaces to prevent the hidden smoke and flames from spreading 15. Figure 1 and Figure 1a below represents a two storey office building, from the dimensions give an estimate for internal room sizes. With reference to Figures 1 and 1a determine: a) Travel distances from each room and each floor, b) Occupancy load c) Purpose group d) Exit and final exit widths e) Stair widths and f) Classification of wall and ceiling linings TRAVEL DISTANCE From the given sketches let the rooms have an average size of 5m by 5m; Therefore the area for each room will be; The travel distances can be determined using a tabular format below; For the ground floor; Room ID Minimum travel Distance from room to the nearest fire Resisting wall(m) Minimum travel distance to the outlet From ground floor(m) G1 G2 G3 G4 G5 G6 G7 G8 G9 G10 G11 When determining the travel distance from floor 2, then it is important to determine the distance through the stairs (Billington, & Copping 2002). Assuming the height of the building to the position of the floor to be 2.8m and the stair length which will give us the travel distance will be determined. The hypotenuse which is the length of the stair before the landing will be determined as; Providing a landing of 1.5m, then the travel distance can be determined as in the table below; Room ID Minimum travel Distance from room to the nearest fire Resisting wall(m) Minimum travel distance to the outlet Floor 2(m) F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 OCCUPANCY LOAD To determine the occupancy load, the area of each room has to be determined (Billington, & Copping 2002), in this case; Assuming the walls’ thickness have a negligible effect on the overall dimension of the building, then the total area occupied will be; For each floor But the total area occupied by persons will be calculated as; on the floor side containing stair enclosures. Using the calculated travel distances, I can use a purpose group of 3 as provided in ADB table . The use of the premises will therefore be offices. After determining the purpose group of the premises, using ADB table C1, the floor space factor m2 /person can then be obtained as 6.0m2/person After determining the floor space factor; then the occupancy load can be determined. Therefore; On the side without stair enclosures; Therefore the total occupancy load in each floor; Since the dimensions are the same in both floors; Exit and final exit widths For floor 2 Minimum no. of exits required; Width of exit for the building; When both exits are functioning as required, each should accommodate But when designing for the worst case scenario if one of the exits malfunctions and only one is available for escape accommodating 76 persons; then; For ground floor Minimum no. of exits required; Width of exit for the building; When both exits are functioning as required, each should accommodate But when designing for the worst case scenario if one of the exits malfunctions and only one is available for escape accommodating 152 persons; then; The formula used in calculating the final exit using the merging flows at final exit as given below; as provided in figure 15 in the ADB document; Since the number of people (N) entering the lobby from the ground floor exceeds 60, i.e. 76persons are available. The distance from the foot of the stair, or the storey exit , to the final exit should be a minimum of 2m (ADB document note) Therefore; Stair widths Referencing to ADB TABLE 7, a stair width of 1000mm should be provided to accommodate the escaping persons safely. Classification of wall and ceiling linings Location National Class European class Small area of rooms not more than 30m2 in non-residential accommodation. 3 D-s3,d2 Works cited Top of Form Billington, M. J., Ferguson, A., & Copping, A. G. (2002). Means of escape from fire. Oxford, Blackwell Science. Gypsum Association (U.S.). (1977). Fire resistance design manual: fire resistance, sound control, structure design. Evanston, Ill, Gypsum Association. Ignall, E., Rider, K. L., & Urbach, R. (1978). Fire severity and response distance initial findings. Santa Monica, CA., Rand. Patterson, J., & Dembowski, J. (2011). The fire. New York, Little, Brown. United States. (1976). Increasing blast and fire resistance in buildings: design techniques for combined nuclear weapons effects. Washington, U.S. Dept. of Defense, Defense Civil Preparedness Agency. Bottom of Form Read More