Performance-Based Fire Safety Design - Assignment Example

Part A: Discuss the different types of fire testing. There are mainly two type of fire testing one if national test and other is European test. National test is BS 476 fire tests on building materials and structures. It includes part 20 to 24. Part 20 deals with method for determination of the fire resistance of the elements of construction. Similarly, part 21, 22, 23 and 24 also deal with fire safety. For example, part 24 lays down method for determination of the fire resistance of ventilation ducts (or to 476-8:1972 in respect of items tested or assessed prior to 1 January 1988). (European tests) commission decision 2000/367/EC of 3rd May 200 implementing council directives 89/106/EEC as regards the classification of the resistance to fire performance of construction products, construction works and parts thereof. Relevant European fire test methods are BS EN ISO 1182:2002, BS EN ISO 1716:2002, BS EN 13823:2002, BS EN ISO 11925-2:2002, BS EN ISO 13238:2001. How do small scale experiments relate to large scale experiments and real fire situations? When real fire situation occurs then all the experiments whether they are small or on large scale help the residents to escape the fire. Discuss the objectives of fire safety and the five tactics available to the fire safety designers seeking to fulfill the fire safety objectives? Define fire engineering and discuss its importance. Objectives of fire safety- a). To limit damage to the building caused by heat, smoke and firefighting water, b). To limit damage to the contents of the building caused by heat, smoke and firefighting water, c). To allow the business to be trading in as short a time as possible following a fire, thus limiting a business interruption. Fire safety designers use various tactics to ensure fire safety; it includes the following: 1. Escape routes; 2. Compartmentation and separation, fire doors, self-closing fire doors and other doors equipped with relevant hardware (e.g. panic locks); 3. Location of fire and smoke detector heads, alarm call-points, detection alarm control boxes, alarm sounders, fire safety signage, emergency lighting, fire extinguishers, dry or wet risers and other fire fighting equipments and locations of hydrants outside the building; 4. Any sprinkler system including isolating valves and control equipments 5. Any smoke control system(s) (or ventilation system with a smoke-control function), including mode of operation and control system. Fire engineering is a vital aspect of all building design processes. Using expert knowledge of the response of people and buildings to fire, our fire engineering team facilitate architectural vision and address client needs, such as business continuity and property protection. Name and define four parameters you can determine using the cone calorimeter. A cone calorimeter is a modern device used to study the fire behavior of small samples of various materials in condensed phase. It is widely used in the field of Fire Safety Engineering. The four parameters associated with it are ignition time, mass loss, combustion products, heat release rate and other parameters associated with its burning properties. Explain the term “Positive Pressure Ventilation”. Positive pressure ventilation is achieved by applying positive pressure higher than atmospheric pressure at the airway opening. Increasing the pressure at the airway opening produces a pressure gradient that generates an inspiratory flow. This flow in turn results in the delivery of a breath. Explain what the flashpoint of a fuel is. The flash point of a chemical is the lowest temperature where enough fluid can evaporate to form a combustible concentration of gas. The flash point is an indication of how easy a chemical may burn. Materials with higher flash points are less flammable or hazardous than chemicals with lower flash points. Explain what the Limiting Oxygen Index test does and give its limitations. The limiting oxygen index (LOI) is the minimum concentration of oxygen, expressed as a percentage that will support combustion of a polymer. It is measured by passing a mixture of oxygen and nitrogen over a burning specimen, and reducing the oxygen level until a critical level is reached. LOI values for different plastics are determined by standardized tests, such as the ISO 4589 and ASTM D2863. What does it mean if a sample has a high LOI or a low LOI? Use examples to illustrate your answer. Explain the terms “piloted-ignition” and “auto-ignition”. Ignitions are of two types; one is piloted ignition and second is auto ignition. Piloted ignition is the process of initiation and flame propagation in premixed fuel system. Auto ignition occurs without any spark or flame source. The fuel must still be within a specific concentration range and chemical kinetic processes must exceed the ability of the mixture to lose heat. Why is it important to carry out fire testing on materials? It is important to ensure that they won’t break down in the case of real fire situation, Explain what causes a “V” pattern during a fire in a compartment. V-pattern relied upon by many investigators. When hot gases from a fire rise in a natural convection mode, (as a result of heat related gas buoyancy) the gases tend to spread out as they rise, forming a V. Consequently, the fire investigator looks to the base of the V as the origin of the fire. The soot pattern, on the walls of the home, has spread outward near the eaves, suggesting that the fire origin is at grade level. Soot patterns inside the home were less severe, suggesting that the fire started on the outside of the wall. Define the term “heat release rate”. Include diagrams showing heat release rate for thermally thin and thermally thick, charring and non-charring materials. Heat Release Rate (HRR) is the rate at which fire releases energy – this is also known as power. HRR is measured in units of Watts (W), which is an International System unit equal to one Joule per second. Depending on the size of the fire, HRR is also measured in Kilowatts (equal to 1,000 Watts) or Megawatts (equal 1,000,000 Watts). There are five main factors which will affect the development of fire growth within a compartment. They can be divided into two categories: those that are concerned with the compartment itself and those which are concerned with the fuel. Identify these factors. These factors are as follows: 1. Size of compartment 2. Height of compartment 3. Material used to construct the compartment 4. Oxygen in surroundings 5. Surroundings Presented below in table 1, are 10 heat release rates for a piece of laminated wood at 25.00kW/m2. Calculate the range, the mean, the standard deviation and then the uncertainty in the mean and the uncertainty in the standard deviation. Table 1: Heat release rate data Test 1 2 3 4 5 6 7 8 9 10 Heat Release Rate @ 25.00kW/m2 44.80 42.15 42.97 43.60 43.88 44.80 42.79 45.10 41.62 43.74 In table 2 below there is a set of results obtained from the “Bang Box” experiment. Plot a graph which will best show your results and state what the results show. Table 2: Bang box data Fuel Acetone Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Number of Drops 2 6 10 12 14 16 18 20 Height attained by lid (cm) 0 20 40 80 120 150 110 90 PART B – What is the maximum recommended compartment size for each of the following cases: A single storey shop with sprinkler protection- 2000m2 A single storey industrial unit- 2000 m2 to 9000m2 What is the maximum size of an opening (unprotected area) that can be discounted when considering space separation between buildings? Parts of the external wall of an uncompartmented building which are more than 30m above mean ground level may be disregarded in the assessment of unprotected area. 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: An office building with a top occupied floor of 250m2 located at 19m above fire service vehicle access level- fire fighting shaft is not required because it is required when area is 900m2. However, fire fighting lift will be needed as it is located at the height of 19m. A four storey assembly building with a top storey of 1400m2 located 10m above fire service vehicle access level- fire fighting shaft will be needed but fire fighting lift will not be needed. What is the minimum recommended fire resistance periods for the following structures: A 30m high sprinkler protected residential building- 120 minutes A single storey shop with sprinkler protection- 30 minutes What purpose groups would be appropriate for the following premises? A students union building (e.g. 53°) A department store A factory. According to Table 2 of ADB, what are the recommended travel distance limitations (single direction & more than one direction) for the following: A normal hazard storage facility- 25m and 45m respectively A place of special fire hazard- 12 m and 25m The bedroom of an apartment- 9m and 18m A lecture theatre with fixed seating in rows- 15m and 32m Shop floor- 18m 45m Plant room that exits through the accommodation within a building- 9m and 35m According to Table 3 of ADB, what is the recommended minimum number of escape routes from a storey with: 10 people- 1 100 people- 2 200 people- 2 500 people- 2 According to Table 4 of ADB, what is the minimum exit width required to accommodate: 219 people- 1050mm 61 people- 850mm 10 people-750mm 500 people- 5 per person 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: 75 persons- 1000mm 130 persons- 1000mm 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: 155 persons- 1000mm 230 persons-1000mm 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). 2metres According to Table C1, what floor space factors would be appropriate in the following areas? An office- 6 m2/ person A bar- .5 m2/ person A shop- 7 m2/ person A students union (e.g. 53Degrees)- 1.0m2/ person 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. What is meant by the following terms: Life safety- Life safety is related with securing the life of people inside and outside the building against any hazard occurring due to fire. Property protection- It can be defined as design and construction of the building should be in manner so that fire appliances can easily be accessed and property can be protected at the time of fire. Fire resistance- It is ability of a building that for what time duration it can withstand the effects of the fire. Cavity barrier- Cavity barriers are the hidden space, suspended ceilings and hollow walls which are built for the purpose of providing the route in case of fire so that spread of fire and smoke can be controlled within the cavities (Begley 2004). 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: Travel distances from each room and each floor, Occupancy load, Purpose group, Exit and final exit widths, Stair widths and Classification of wall and ceiling linings. References Begley, J. 2004. Performance based fire safety design. [Online]. Available at: http://www.facilitiesnet.com/firesafety/article/PerformanceBased-Fire-Safety-Design--2017 [Accessed on: 18 Jan 2011]. Read More