Building types based on the National Building Code of the Philippines (1977) 21. Table 4. ...... Manual fire alarm; covers the entire building. 4. Fire alarm is ...
INCORPORATING STRUCTURAL AND NON-STRUCTURAL FEATURES OF BUILDINGS IN A FIRE RISK EVALUATION FRAMEWORK AND TOOL THAT DISTINGUISH HAZARD, EXPOSURE AND VULNERABILITY FACTORS Thesis by Diocel Harold M. Aquino BS Civil Engineering
Submitted to the National Graduate School of Engineering College of Engineering University of the Philippines
In partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering (Structural)
National Graduate School of Engineering College of Engineering University of the Philippines Diliman Quezon City
April 2014
ii
Abstract of Thesis Fire tops the list of Philippine disasters averaging at roughly 8,600 reported incidents annually from 2005 to 2012. This translates to approximately 3.6 Billion Pesos worth of losses annually which means 0.05% of the country’s gross domestic product is lost to fire every year. More importantly, for the same time period, the number of casualties averaged at 236. This is equivalent to a 2.4-in-a-million risk of dying in a fire. The risk goes as high as 18-in-a million-fire fatalities, as in the case of some cities. It is imperative as such, that fire risk and its factors be thoroughly understood in order for decision makers and planners to be able to implement mitigating measures more effectively and rationally, or even more selectively. There is a need for a framework that enables systematic evaluation of fire risk that integrates both quantitative and qualitative, conceptual and computational, elements. In this research, life and non-life risk due to fire are viewed as product of three factors namely: hazard, exposure and vulnerability. Building features, both structural and non-structural, are incorporated in the fire risk evaluation in addition to occupants characteristics and other fire risk-related factors. A new framework for the evaluation of fire risk, both to people and buildings, named FiRE! Framework is introduced in this research. A tool for indexing fire risk in buildings, FiREcalc is also developed. The tool calculates a risk index, ranging from 1 to 5, 1 being the most preferable condition and 5 the least, both for life risk and building risk. The tool has been calibrated in this research using Philippine fire statistical data from the Bureau of Fire Protection, as well as from original field surveys on fire loads on buildings. The framework and tool were tested on 15 selected buildings in UP Diliman. The tool demonstrates applicability for structures of similar characteristics.
iii
Table of Contents Approval Sheet...................................................................Error! Bookmark not defined. Acknowledgements ............................................................Error! Bookmark not defined.
Abstract of Thesis ............................................................................................................... ii
Table of Contents ............................................................................................................... iii List of Tables ..................................................................................................................... vi
List of Figures .................................................................................................................. viii 1.
Introduction ................................................................................................................. 1
1.1.
1.1.1. 1.1.2.
Traditional Risk Model ..................................................................................... 4 Hazard-Exposure-Vulnerability Model of Risk ............................................... 5
1.2.
The Fire Triangle .................................................................................................. 7
1.4.
Building Features ................................................................................................. 9
1.3. 1.4.1. 1.4.2.
Fire Load .............................................................................................................. 8 Building Elements: features and contents ........................................................ 9 Structural and nonstructural features of a building ........................................ 10
1.5.
Statement of the Problem ................................................................................... 11
1.7.
Conceptual Framework ...................................................................................... 12
1.6. 1.8. 2.
Risk and Risk Models .......................................................................................... 3
1.9.
Objectives ........................................................................................................... 11 Scope and Limitations ........................................................................................ 16
Significance of the Study ................................................................................... 17
Related Literature ...................................................................................................... 18
2.1.
Effect of building features on fire risk ............................................................... 18
2.1.1.
Fire risk and building elements: statistical relationship based on the US
National Fire Protection Association report (Ahrens, 2013) ....................... 18
iv 2.1.2.
Fire safety requirements for Philippine buildings ........................................ 20
2.1.4.
Fire load and its effect on building fires ...................................................... 24
2.1.3. 2.1.5. 2.1.6.
2.2.
2.2.2.
Fire safety engineering................................................................................. 25 FSES Risk Indexing for Health Care facilities (Nelson & Shibe, 1978) ..... 27 Risk Standardization Method for Assembly Occupancies (Han, 2011) ...... 28
2.3.
Multi-hazard Framework.................................................................................... 29
3.1.
Identification of Key Building Features Relating to Fire Safety ....................... 31
3.3.
Development of a building survey tool for fire risk evaluation ......................... 32
Methodology .............................................................................................................. 31
3.2. 3.4. 4.
Other parameters contributing to fire risk in buildings ................................ 24
Fire Risk Evaluation Methods ............................................................................ 26
2.2.1.
3.
Building features in performance based design for fire safety .................... 22
3.5.
Development of a fire risk evaluation framework ............................................. 31
Development of a fire risk index calculator ....................................................... 32 Evaluation of buildings in UP Diliman using the framework and tool .............. 33
Results and Discussion .............................................................................................. 35
4.1.
Key Building Parameters Contributing to Fire Risk .......................................... 35
4.3.
FiRE Checklist ................................................................................................... 39
4.2. 4.4.
FiRE! Framework: a framework for fire risk evaluation ................................... 36
FiREcalc: Fire Risk Index Calculator ................................................................ 39
4.4.1.
Sub-factors and indicators relating to Fire Risk to Life ............................... 40
4.4.3.
Weights of the indicators and sub-factors .................................................... 63
4.4.2. 4.4.4. 4.4.5.
Other Sub-factors and indicators relating to building risk ........................... 61 Calculation of the Fire Risk Indices............................................................. 63
Risk Equivalence of the Fire Risk Indices ................................................... 64
v 4.6. 5.
4.7.
Evaluation of UP Diliman buildings using FiREcalc......................................... 67
Calibration methods for FiREcalc ...................................................................... 70
Summary and Recommendations .............................................................................. 71
5.1. 5.2.
Summary and Conclusion .................................................................................. 71
Recommendation for Future Work .................................................................... 73
References ......................................................................................................................... 74 Appendix A: FiRE Checklist with annotations
Appendix B: FiREcalc results for the 15 surveyed UP Diliman Buildings Appendix C: FiRE Checklist applied to 15 UP Diliman Buildings Appendix D: Fire Load Summary for surveyed UP Diliman Buildings Appendix E: Compartment Fire Loads in UP Diliman Buildings Appendix F: Sample FiREcalc Calculations
vi
List of Tables Table 1. Analogy of building elements, structural design and fire safety terminology ...... 9 Table 2. Building characteristics affecting fire risk (Fire Code, 2008) ............................ 20 Table 3. Building types based on the National Building Code of the Philippines (1977) 21 Table 4. Effect of fire on the performance of building feature ......................................... 23 Table 5. Effect of building features on life and non-life risk............................................ 36 Table 6. FiREcalc Scores for Fire Load Density .............................................................. 40 Table 7. FiREcalc Scores for Building Service Equipment .............................................. 42 Table 8. FiREcalc Scores for Hazardous Sectional Use ................................................... 42 Table 9. FiREcalc Scores for Potential External Fire ....................................................... 44 Table 10. FiREcalc Scores for Structural Framing ........................................................... 45 Table 11. FiREcalc Scores for Compartment Separation ................................................. 47 Table 12. FiREcalc Scores for Building Height ............................................................... 47 Table 13. FiREcalc Scores for Fire Suppression Systems ................................................ 48 Table 14. FiREcalc Scores for Distance from Fire Station (Han, 2011) .......................... 49 Table 15. FiREcalc Scores for Ventilation ....................................................................... 50 Table 16. FiREcalc Scores for Smoke Protection ............................................................. 51 Table 17. FiREcalc Scores for Building Exit Door .......................................................... 52 Table 18. FiREcalc Scores for Corridors, Hallways and Floor Exits ............................... 52 Table 19. FiREcalc Scores for Room and Intermediate Egress ........................................ 53 Table 20. FiREcalc Scores for Stairways ......................................................................... 53 Table 21. FiREcalc Scores for Areas of Safe Refuge ....................................................... 54 Table 22. FiREcalc Scores for Emergency Lights ............................................................ 55
vii Table 23. FiREcalc Scores for Emergency Evacuation Plan ............................................ 56 Table 24. FiREcalc Scores for Exit Signs ......................................................................... 56 Table 25. FiREcalc Scores for Alarm System .................................................................. 57 Table 26. FiREcalc Scores for Population Density .......................................................... 57 Table 27. FiREcalc Scores for Duration of Stay............................................................... 58 Table 28. FiREcalc Scores for Mobility and Walking Ability ......................................... 58 Table 29. FiREcalc Scores for Alertness of Occupants .................................................... 59 Table 30. FiREcalc Scores for Fire Evacuation Training and Drills ................................ 60 Table 31. FiREcalc Scores for Firefighting Training and Fire Brigades .......................... 60 Table 32. FiREcalc Scores for Access to Firefighting and Escape Equipment ................ 60 Table 33. FiREcalc Scores for Movable Fire Load Density Scores ................................. 61 Table 34. FiREcalc Scores for Floor Area ........................................................................ 62 Table 35. FiREcalc Scores for Cost per Square Meter ..................................................... 62 Table 36. FiREcalc risk index descriptions ...................................................................... 64 Table 37. FiREcalc alternative life risk index equivalence (proposed) ............................ 64 Table 38. FiREcalc alternative building risk index equivalence (proposed) .................... 66 Table 39. Life risk and risk factor indices for 15 buildings in UP Diliman ..................... 67 Table 40. Building risk and risk factor indices for 15 buildings in UP Diliman .............. 68 Table 41. Summary of Life Risk and Building Risk Indices for the surveyed UP Diliman Buildings ............................................................................................................ 72
viii
List of Figures Figure 1. Hazard-Exposure-Vulnerability (HEV) Risk Model ........................................... 5 Figure 2. Risk reduction by reducing the risk factors ......................................................... 6 Figure 3. Fire Triangle ........................................................................................................ 7 Figure 4. Parallelism of fire risk evaluation methods and fire safety design approaches . 13 Figure 5. Conceptual framework for building risk due to fire .......................................... 14 Figure 6. Conceptual framework for life risk due to fire .................................................. 15 Figure 7. Loss of lives in a fire as attributed to the item first ignited ............................... 18 Figure 8. Percentage of direct property damage as attributed to the item first ignited ..... 19 Figure 9. Loss of lives in a fire as attributed to the item contributing most to fire spread 19 Figure 10. Percentage of direct property damage as attributed to the item contributing most to fire spread. ........................................................................................... 20 Figure 11. Factors affecting human response during a building fire (Kobes, et al., 2010) .......................................................................................................................... 24 Figure 12. Fire risk tree diagram by Han (2011) .............................................................. 28 Figure 13. Detailed FiRE! Framework for Life Risk........................................................ 37 Figure 14. Detailed FiRE! Framework for Building Risk ................................................ 38 Figure 15. Process flow diagram for FiREcalc: Building Service Equipment ................. 41 Figure 16. Process Flow Diagram for FiREcalc: Hazardous Sectional Use ..................... 43 Figure 17. Process Flow Diagram for FiREcalc: Potential External Fire ......................... 44 Figure 18. Process Flow Diagram for FiREcalc: Structural Framing Material ................ 45 Figure 19. Process Flow Diagram for FiREcalc: Compartment Separation ..................... 46 Figure 20. Process Flow Diagram for FiREcalc: Built-in Fire Suppression System ........ 48
ix Figure 21. Process Flow Diagram for FiREcalc: Accessibility to Firefighters ................ 49 Figure 22. Process Flow Diagram for FiREcalc: Smoke Protection ................................ 50 Figure 23. Process Flow Diagram for FiREcalc: Building Exit Door .............................. 51 Figure 24. Process Flow Diagram for FiREcalc: Corridors and Floor Exits .................... 52 Figure 25. Process Flow Diagram for FiREcalc: Area of Safe Refuge ............................ 54 Figure 26. Process Flow Diagram for FiREcalc: Automatic Emergency Lights .............. 55 Figure 27. Process Flow Diagram for FiREcalc: Emergency Evacuation Plan ................ 55 Figure 28. Process Flow Diagram for FiREcalc: Exit Signs ............................................ 56 Figure 29. Process Flow Diagram for FiREcalc: Alarm System ...................................... 57
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1. Introduction Fire tops the list of the most frequently-occurring Philippine disasters averaging at roughly 8,600 reported incidents annually from 2005 to 2012. This translates to approximately 3.6 Billion Pesos worth of direct property losses annually. This also means that 0.05% of the country’s gross domestic product is lost to fire every year (Saflor, 2013). More importantly, for the same time period, the number of fire fatalities averaged at 236 annually (Velasco, 2013). This is equivalent to a 2.4(10-6) risk of dying in a fire. In Metro Manila where 77% of the fires in the country occur, the probability of death in a fire is 5(10-6). Annual life risk goes as high as 18(10-6) as in the case of Navotas City. In the Philippines, regulatory measures ensuring building fire safety are contained in the Revised Fire Code of the Philippines (R.A. 9514) and the National Building Code of the Philippines (P.D. 1096). The code sets minimum requirements on buildings concerning fire safety, including but not limited to fire suppression, fire prevention, and safe egress of occupants during a fire. On the management side, it is important that these provisions be implemented as necessary. In the Philippines, we have the Bureau of Fire Protection (BFP) checklist as a building assessment tool. BFP conducts checks during construction, before occupancy and periodically to ensure that regulatory requirements are complied with. The level of safety, or risk, is characterized by compliance or non-compliance to the standards. This qualitative risk assessment method can be accomplished in a short span of time. This evaluation does not tell much about risk levels, however, or about risk drivers. Rather, it judges a building as either fully compliant or noncompliant. The current method is also
2 limited to the judgment of the inspectors who are deemed to be experts in fire safety and cannot be conducted by non-specialists. This fire safety implementation through the use of the BFP Fire Safety Checklist results to building features being designed in the context of prescriptive-based approach, one that is restricted to full compliance to predetermined standard requirements. This is in contrast with the more optimized performance-based approach, which considers design flexibility based on the building’s purpose and context (Hadjisophocleous & Benichou, 1999). It is imperative, as such, that fire risk and its factors be thoroughly understood in order for us to be able to implement mitigating measures more effectively and rationally, or even more selectively. On the other end of the spectrum, there is the quantitative approach which fits perfectly with performance-based design. This method is able to calculate risks, and even generate probability values for fire risk. Given sufficiency in the required information, this is useful for building designers and decision-makers in optimizing building design in protecting the building and its occupants against fire. This method of risk evaluation, however, cannot be done on the non-specialist level as this requires a high level of technical knowledge and expertise. It requires intensive data collection, modeling, simulation and computation. This also means that quantitative methods take longer time to implement than a purely qualitative risk evaluation. Semi-quantitative method involves the systematic combination of both qualitative and quantitative parameters to give a measure of risk. This is typically done by means of indexing. Scores are assigned to various states of the parameters that are checked and are combined together to arrive at an index, which is deemed representative of the risk level.
3
1.1. Risk and Risk Models Risk can be classified as either life risk or nonlife risk. Pacheco (2007) proposed three generic objects of risk namely: people, way of life and property. Risk posed to people is classified as life risk. This risk may translate to mortality or morbidity, casualties or injuries. Nonlife risk, on the other hand, involves property and way of life as risk objects. Building risk is a subset of nonlife risk. Nonlife risk may translate to either direct or indirect losses. Direct losses involve those that manifest physically as consequence of exposure to a certain hazard. Such is the case when properties become damaged or destroyed. Indirect losses include those that may arise due to disruptions in the way of life. This includes economic losses arising from interruption in business operations, lost productive time and the likes. Risk is typically expressed in terms of the probability of occurrence. There is, however, a need to express it in a way that is easily comprehensible by the public (Bukowski, 1996). Economic value of the associated losses is typically the metric used for nonlife risk. For this metric to be applicable to life risk, it necessary for human life to be associated with a corresponding economic value. This is typically done by getting the present worth of the anticipated income streams for the rest of a person’s productive life (Philips, 1994). This approach, however, has encountered great objection as it reduces the value of human life to the anticipated income, and also because of the concept that some people are of less value than others (Hadjisophocleous & Fu, 2004). This is among the reasons why life risk and nonlife risk are treated separately. For earthquakes and other phenomena where the events are so sudden that people have little or no chance to evacuate hazardous or risky buildings, life risk is taken as
4 mainly consequential to building risk. This means that failure of the building results to fatalities in its occupants. Design and evaluation for life safety becomes tantamount to building safety, which is just a function of the hazard magnitude and the building vulnerability. Specifically for fire, which in most cases allows time for the occupants to evacuate, life risk now becomes an interplay of the two aforementioned factors plus the effects of building features, occupants’ characteristics, and situational conditions (Kobes, et al., 2010). Even for building risk, situational parameters come into play. 1.1.1. Traditional Risk Model Imperative to risk mitigation is the assessment of the gravity of risk. Over time, various models have been used to represent risk. Risk is traditionally modeled as follows: =
The model considers two things: likelihood, which is defined as the probability of occurrence of the risk-triggering factor, and impact, which is the magnitude of the anticipated impact or consequence to the affected population. This model is typically used in the prioritization of specific risks to be addressed. It does not, however, point out to the specific factors that drive the risk, which if better understood, would enable more systematic and more effective risk mitigation. For this study, a different perspective is taken. Risk is defined by three factors, namely hazard, exposure, and vulnerability (Uitto, 1998). The basis for this is that hazard may transform into a disaster if and when there are exposed elements that are vulnerable. (Pacheco, 2007)
5
1.1.2. Hazard-Exposure-Vulnerability Model of Risk Hazard is any dangerous condition, activity or substance that may cause harm to people, properties and way of life. Hazard could be natural, as in volcanic eruption or spontaneous combustion, or anthropogenic, as in arson and accidental fires. It is the first potential for risk. Vulnerability on the other hand is the collection of characteristics of the element at risk that makes it susceptible to damage or loss. Exposure is the extent of the elements’ contact to the hazard. (UNISDR, 2009) Hazard only translates to a disaster when it affects an exposed population, of people or buildings, which is vulnerable. Therefore, risk can be equated to the product of these three factors. To illustrate, a hazard does not pose risk to an exposed invulnerable population. So will there be no risk without an exposed and vulnerable population.
Figure 1. Hazard-Exposure-Vulnerability (HEV) Risk Model
6
Figure 2. Risk reduction by reducing the risk factors In the HEV Model, risk can be diminished by reducing one of its factors: by reducing the vulnerability of exposed elements, by removing exposed elements from the hazard, and by reducing the hazards that pose danger to the element at risk. Variations of this risk model include R = H x V, where risk is computed only for exposed elements or for instances where the exposure factor is embedded in the either of the two others factors, more typically in the vulnerability. Other models consider capacity as a determinant factor of risk. UNISDR (2009) defines capacity as “the combination of strengths, attributes and resources available within a community, society or organization that can be used to achieve goals.” Capacity is incorporated in the equation as in R = H x E x V / C. In the context of this research, when treating life risk, the capacity of the occupants is treated as counter-vulnerability and is coupled with it.
7
1.2. The Fire Triangle A popular conceptual model in fire safety science is the fire triangle. It illustrates the three elements necessary for fire to start and subsist, namely: heat, oxygen and fuel.
Figure 3. Fire Triangle In order for a fire to start, ignition temperature must be reached. Potential heat sources include open flame, solar radiation, extremely hot surfaces, friction, chemical action and compressed gas. Heat transfer mechanisms include conduction, convection and radiation. In other models, heat is interchanged with ignition source. Fire needs an atmosphere with 16% oxygen for it to subsist. Air in the earth’s atmosphere exists with 21% oxygen. This means that fire is likely to subsist if there is a constant supply of air into the compartment where the fire is, such is the case when the area is well-ventilated. Other oxidizing agents may also take the place of oxygen. Fuel includes any combustible material that may be exposed to the heat or ignition source. Fuel material inside a building compartment is referred to as fire load.
8 A variant of the fire triangle is the fire tetrahedron which introduces chain reaction as the fourth factor contributing to the spread of fire.
1.3. Fire Load Fire load is the totality of the heat release potential of all combustible materials in a building. The severity of fire is directly proportional to the amount of fire load. Fire load density is the amount of fire load per square meter of floor area of the building compartment, and is expressed in mega joules per square meter (MJ/m2). Fire load density is computed as follows: = Where
∑
Qf = Fire Load Density (MJ/m2) mi = mass of the ith combustible material (kg) Hi = calorific value of the ith material (MJ/kg) Af = floor area of the compartment (m2)
Fire load can be classified in terms of fixity, as either fixed or movable, and in terms of material composition, cellulosic or noncellulosic. Fixed fire load are combustible materials that are permanently attached to the building and that which could be exposed to ignition sources. It includes doors and windows, built-in cupboard, shelves and cabinets, ceilings and framing elements like beams and columns. Movable fire load, on the other hand, are combustible items that could easily be brought into or taken out of a fire compartment. It includes furniture, equipment,
9 personal belongings, drapes, papers, as well as rubbish. The movable combustible materials vary with occupants’ lifestyle and room usage, among other factors. Some combustible materials are less likely to burn in a fire due to protection provided by shelving which causes delay in the spread of fire into these materials. This fraction of movable fire load is called protected fire load. Examples of such are shelved books or clothes in a cabinet. For these items, the decrease in the potential for combustion is called the derating factor, which is applied as a reduction factor for the weights of shelved and contained combustible materials. In terms of material composition, cellulosic fire load consists of wooden and paper materials, while noncellulosic fire load includes plastics and combustible metals.
1.4. Building Features 1.4.1. Building Elements: Features and Contents Elements in a building could be classified as either building feature or content (GMMA RAP - UP ICE, 2014). Building features include those that are fixed or are permanently attached to the building. Contents, on the other hand, are highly temporal in position and situation within the building. It covers a diverse range of items and typically varies with the building’s occupancy type and usage. Table 1. Analogy of building elements, structural design and fire safety terminology
Building elements classification (GMMA RAP - UP ICE, 2014) Building features Contents
Structural Design
Fire Safety
Dead Load
Fixed Fire Load
Live Load
Movable Fire Load
10
.Building features and contents are analogous to dead load and live load in structural design respectively. In fire safety terminology, building features closely associate with fixed fire load while contents relate to what is called movable fire load. 1.4.2. Structural and Nonstructural Features of a Building In the context of this research, features of a building are classified as either structural or nonstructural. Structural features include building features and characteristics that are integral to the design of buildings for strength under normal loading conditions, as well as for resilience to extreme scenarios and conditions, as in earthquakes, severe winds and fire. This includes the conventional definition of structural members, which refer to elements resisting gravity load and lateral forces. Examples of which are beams, columns, slabs, load-bearing walls and trusses. Compartmentation and partitions also play a significant role in building resilience, particularly against fire. Proper compartment design is necessary in the prevention of fire spread throughout the building. Doors and windows are also included in the definition of structural features as their placement and condition, along with that of other openings, may affect fire propagation or containment within a building compartment (Bukowski, 1996). Following the same definition, building geometry, which includes the height, floor area, shape, and layout, is considered as structural feature. Features that are accessorial in nature are classified as nonstructural. Electromechanical components, architectural elements and decorations, and building service
11 equipment such as elevators, generators, boilers and HVAC systems are included in this category. In the context of fire safety, important nonstructural features also include emergency safety features such as alarm systems, exit signs and emergency lighting systems.
1.5. Statement of the Problem There is a need for a framework and a tool that enable systematic evaluation of fire risk to life and buildings, and that integrate both conceptual and computational elements. The study seeks to answer the following research questions: 1. How do building features, both structural and non-structural, fit into the hazardexposure-vulnerability framework for fire risk evaluation? 2. What other factors affect life risk and building risk to fire? 3. How do UP buildings fare when it comes to fire safety?
1.6. Objectives The objectives of the study are as follows: 1. To identify building attributes and features, both structural and non-structural, contributing to fire risk on a building (building risk) and its occupants (life risk) 2. To develop a fire risk evaluation framework, FiRE! Framework, considering hazard, exposure and vulnerability as distinct risk factors with corresponding sub-factors, either for building risk or life risk
12 3. To develop an improved building fire safety survey checklist, FiRE Checklist, based on the aforementioned framework for corresponding recommendation to the Bureau of Fire Protection 4. To implement an easy-to-use and easy-to-calibrate calculation tool, FiREcalc, for the assessment of buildings in regard to fire risk; calibrated by means of statistical data from previous fire occurrences and/or field survey data, and recalibratable by additional future data from laboratory, field and/or fire incident statistics 5. To evaluate selected UP academic buildings using the calibrated tool, and consequently recommend possible strategies that are applicable and/or selectable to mitigate fire risk factors in these buildings.
1.7. Conceptual Framework Fire risk evaluation methods can be seen as parallel to fire safety design approaches. In the Philippines where the state of practice is predominantly prescriptive-based, building safety against fire is evaluated mostly by means of checklists, as in the BFP Checklist, and narratives. The proposed framework (FiRE! Framework) and tool (FiREcalc) employ a semi-quantitative approach. Both qualitative and quantifiable elements are checked and subsequently assigned with scores. These elements are computationally combined to arrive at an index that is deemed representative of the level of risk (or conversely, safety) in the building.
13
Figure 4. Parallelism of fire risk evaluation methods and fire safety design approaches It is foreseen that in the adequacy of necessary data, when supplemented by expert judgment, Philippine practice can eventually shift into a quantitative approach for risk evaluation particularly for important buildings and critical infrastructures. The merit of qualitative and semi-quantitative approaches is not diminished nonetheless as they find their niche when rapid and/or frequent assessment is deemed necessary. Life risk and building risk due to fire are separately evaluated in this study. While building risk is conveniently translatable to economic terms, putting a monetary value to life is more complicated. Further, in the context of fire risk, life peril is not necessarily consequential to building risk. Both life risk and building risk are assessed in this study as functions of building features, structural and nonstructural, and other factors affecting fire and human behavior.
14
Figure 5. Conceptual framework for building risk due to fire Placing in the context of the hazard-exposure-vulnerability framework, anything that may start a fire poses hazard to a building. This includes all three elements in the fire triangle: fuel, heat or ignition source, and oxygen or an alternative oxidizing agent. Vulnerability and exposure, on the other hand, are defined by the building features. Features that define the inherent weakness, or strength, of the structure against fire fall define the building’s vulnerability. Features that may decrease or magnify the extent of losses, such as building size and cost per square meter of the building, are exposure determinants. Factors affecting fire risk to life, on the other hand, include building features, occupants’ characteristics and fire characteristics, among others (Kobes, et al., 2010). Each of the distinct factor may relate to either hazard, vulnerability or exposure.
15 Three things may lead to fatalities or injuries in a building fire: smoke and toxic gas inhalation, exposure to flame or extreme temperatures, and debris resulting from collapse of burning building features. Exposure to these three is determined by three factors namely: structural and nonstructural building features, fire-starting elements, as well as situational factors. These constitute hazards to life.
Figure 6. Conceptual framework for life risk due to fire Vulnerability is reflected by the occupant behavior and characteristics while exposure is determined by the number of people in the building and the corresponding duration of stay in the building. Capacity is determined by the trainings that the occupants undergo in regard to evacuation, firefighting and rescue. These factors are lumped with the vulnerability factors. The factors’ association with the corresponding risk factor may vary depending on the object of risk, whether people or the building itself, depending on the externality or inherence to the element at risk. In principle, if a parameter aggravating risk is inherent to the element, it is classified as vulnerability. If it is external to the object, it becomes hazard.
16
1.8. Scope and Limitations The study covers how typical different building features, both structural and nonstructural, as well as other factors, translate to fire risk. The study covers both life risk and building risk due to fire. Fire load is calibrated using data gathered from fire load surveys originally conducted on 15 buildings in UP Diliman, along with results from fire load surveys in published researches. Datasets on Philippine fire incidences were obtained from the Bureau of Fire Protection for national and Metro Manila scale, and from the Quezon City Fire Department for a more detailed data on fire incidences in barangays of Quezon City. The fire risk evaluation tool, FiREcalc, has been implemented and calibrated for 15 buildings in UP Diliman. The buildings represent various occupancy types: academic, residential, office and storage. The samples also cover buildings of various heights (1 to 5 storeys), of different vintages and occupants’ population. The developed fire risk calculation tool, FiREcalc, is designed to be initially applicable for the assessment of institutional, commercial, and industrial buildings, as well as for residential buildings with multiple dwelling units. In principle, it is more apt for buildings with a relatively high number of occupants as opposed to single-family residential buildings that require much simpler fire safety measures. The tool may also not very well apply to buildings at the other end of the spectrum, the extremely high ones, like skyscrapers that usually require specialized designs and measures for fire safety.
17
1.9. Significance of the Study Dividing risk into component risk factors allows better approaches in disaster risk management; we will know which specific root causes (or “risk drivers”) to address. It allows for more systematic alleviation of fire risks in buildings by addressing the specific problematic risk component. The framework enables decision-makers (e.g. building administrators) to properly address the risk in buildings - for example, if hazard is high, then retrofit could be done; if vulnerability is high and/or capacity is low, fire safety training could be conducted; if exposure is high, then the occupancy and building traffic could be more properly planned. Currently, risk arising from multiple natural hazards such as earthquakes, severe winds and floods are being studied in the context of Hazard-Exposure-Vulnerability (HEV) Framework. Studying fire risk in the same paradigm would allow better disaster risk reduction by incorporating fire in the multi-hazard approach. In particular, vulnerability management for people and buildings should be on a multi-hazard scale in order to avoid measures that will strengthen the element at risk against one hazard but, unintentionally, weaken it against another. The framework could be instrumental to the further development of Philippine fire safety standards and the tools could be used by non-specialists for the rapid evaluation of buildings for fire risk, and by specialists for detailed evaluation of buildings. Among the study’s
significant
contribution
is
an
improved
Fire
Safety Checklist
and
recommendations for fire risk analysis and reduction. Further, the study could provide a supplemental or alternative method in insurance risk quantification for people and buildings.
18
2. Related Literature 2.1. Effect of building features on fire risk 2.1.1. Fire risk and building elements: statistical relationship based on the US National Fire Protection Association report (Ahrens, 2013) Both building features and contents contribute to the life risk and building risk due to fire. A study conducted by Ahrens (2013) on US National Fire Protection Association data on residential fires from 2007-2011 shows the item that is first ignited and that which contributes most to fire spread. Of the 91,100 fire incidences in the 5-year study period, 51% are traceable to building features being the item first ignited. The same also constitutes 24% of cases leading to loss of lives and 50% of the total direct damage brought about by fires.
Figure 7. Loss of lives in a fire as attributed to the item first ignited
19
Figure 8. Percentage of direct property damage as attributed to the item first ignited Considering the item contributing most to fire spread, the figures are even more pronounced. Sixty four percent of cases could be attributed to building features as the main cause of fire spread. The same accounts for the spread of 47% of deadly fires and 69% of direct property damages in fires.
Figure 9. Loss of lives in a fire as attributed to the item contributing most to fire spread
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Figure 10. Percentage of direct property damage as attributed to the item contributing most to fire spread. 2.1.2. Fire safety requirements for Philippine buildings The Revised Fire Code of the Philippines (R.A. 9514) sets requirements for various building features that have impact on fire safety in buildings. Table shows the various identified characteristics categorized in terms of their effect on fire safety. Table 2. Building characteristics affecting fire risk (Fire Code, 2008)
Factors relating to fire ignition and spread
Factors relating to fire extinguishing
Factors relating to safe egress
Factors relating to air supply and smoke control
Hazard brought about by contents Building service equipment Construction and Compartmentation Egress means Lighting and signs Emergency evacuation plan Fire Alarm
Automatic fire suppression systems Standpipes Portable fire extinguishers Ventilation Smoke spread controls
21
The occupancy type, i.e. the classification for which the building is used, is the primary determining parameter that is checked in the fire safety assessment in accordance to the Fire Code. Requirements on the aforementioned building characteristics vary with occupancy type. The code classifies buildings into the following types: assembly, educational, health care, detention and correctional, residential, mercantile, business, industrial, storage, mixed occupancies, and miscellaneous occupancies. In addition to building characteristics, other factors considered by the Fire Code as related to fire risk include fire safety training and organization of the occupants into fire brigades. These factors are characteristics of the building occupants. The National Building Code of the Philippines (P.D. 1096) also classifies buildings into five types based on varying degree of resistance to fire. Table 3. Building types based on the National Building Code of the Philippines (1977) Type Description I Buildings of wood construction II Buildings of wood construction with protective fire-resistant materials and one-hour fire-resistive throughout III Masonry and wood construction; one-hour fire-resistive throughout; with incombustible, fire-resistive exterior walls IV Steel, iron, concrete or masonry construction; walls and permanent partitions are incombustible V Building is fire-resistive; structural elements, walls and partitions shall be incombustible, fire-resistive material (steel, iron, concrete or masonry construction)
22 2.1.3. Building features in performance based design for fire safety With the imminent worldwide shift in the fire safety design from prescriptive to performance-based approach, building features are now being designed based on their performance in minimizing life risk to occupants, as opposed to compliance with hardcoded specifications. This provides plenty of room for flexibility and innovations in fire protective solutions. This would also allow the proliferation of cost-effective and innovative technologies in fire protection. (Hadjisophocleous & Benichou, 1999) In the performance-based design of buildings for fire, components are not evaluated singly, but in combination with the other components comprising the building. Fire risk is evaluated by means of simulation of scenarios, incorporating conditions specific to the building. Scenarios are developed to determine the potential fire behavior and consequences. Details of these scenarios include room dimensions and layout, contents, construction materials, ventilation, position of doors and non-building parameters such as the location, characteristics and number of occupants. (Bukowski, 1996) Room layout and dimensions, position of openings like doors and windows, and similar spatial parameters are checked for their effect on fire propagation or containment, as well as for their impact on occupants egress from the building during a fire. Building materials are generally evaluated in terms of ignitability by various heat transfer mechanisms such as radiation, conduction and convection. The British Standards provide information on such characteristics for typical building materials. Fire growth parameters, which include the burning rate, heat release rate and calorific values, are also considered for analysis.
23 The anticipated effect of fire on the expected performance of typical physical building features is also analyzed as shown in Table 4. Stability refers to the structural soundness and prevention from collapse. Integrity is the ability to prevent fire and smoke from going beyond the compartment of origin. Insulation pertains the prevention of extreme temperatures on the side of the component that is not exposed to fire. (Buchanan, 1994) Table 4. Effect of fire on the performance of building feature Building feature Stability Integrity Insulation Partition X X Load-bearing wall X X X Floor or ceiling X X X Beam or column X Stroup (1997) stressed the importance of fire suppression features such as smoke and heat detectors, and an integrated sprinkler system. These features are quantified for response and activation time. Also a main objective typically defined in the performance-based building design is to allow safe egress from the building during a fire. The available safe egress time (ASET), which is defined by paths and means of egress and the walking speed, is compared against the required safe egress time (RSET), which is determined typically by the occupant’s exposure to extreme heat and to toxic gases and irritants generated by the burning building materials and contents. (Yao, et al., 2013) Compartmentation of the staircase play an important role in multistory buildings. According to Kobes (2010), fire casualties in multistory buildings are strongly correlated with presence of fire and/or smoke in the staircases.
24 2.1.4. Fire load and its effect on building fires Three factors affect the severity of compartment fires: fire load, ventilation and fuel surface area. These three control the size of the fire in a compartment. Fire load is quantified by means of inventory, direct weighing, questionnaire or combination of the prior methods. Both inventory and direct weighing methods require the surveyor to be physically inside the building. Questionnaire method involves conduct of either a paper survey or an electronic one, in order to determine the quantity and characteristics of the combustible materials in a compartment. 2.1.5. Other parameters contributing to fire risk in buildings Fire Response Performance Human Features Individual Features: Personality, Knowledge and Experience, Power of observation, Power of Judgement, Power of Movement Social Features:
Affiliation, Task fixation, Role and responsibility Situational Features: Awareness, Physical position, Familiarity with layout
Building Features Engineered Features: Layout, Installations, Materials, Compartments, Size of Building Situational Features:
Focus point, Occupant density, Ease of wayfinding, Building evacuation team, Maintenance
Fire Features Perceptual Features:
Visual, smelling, audible, tangible Fire Growth Rate Smoke Yield Toxicity Heat
Figure 11. Factors affecting human response during a building fire (Kobes, et al., 2010)
25 Factors affecting human response and behavior during a fire can be classified into three: building features, human features and fire features (Kobes, et al., 2010). Aside from the building features prior mentioned, human features and fire features also affect life safety during a building fire. The toxic gas emission of substances and materials in the building during a fire may incapacitate even those who are able-bodied and mobile, in the presence of asphyxiants and pulmonary irritants. (Hartzell, 2001) Furthermore, infants, children, elderly and asthmatics have greater sensitivity to these fire effluent toxicants. Fatal fires also occur primarily at night specifically in buildings where people stay either unconscious, non-alert, or impaired in mobility. Examples are in residential buildings where people sleep, in healthcare facilities where patients are confined or in prison facilities where occupants are detained. Fire fatalities are also common in dense assembly areas (Kobes, et al., 2010). 2.1.6. Fire safety engineering There are three levels of prevention in the context of fire safety: (1) prevention of ignition, (2) active and passive fire protection to prevent exposure of occupants, and (3) ensuring that the consequences are not serious and that safe egress from the building is possible. (Hartzell, 2001) The first line of fire protection is to prevent the start of fire in any building. This, however, may be impossible in buildings or building compartments where fire and ignition sources are integral to its purpose and occupancy, as in kitchens, laboratories, and similar facilities. In such case, the next line of defense would be to provide
26 equipment and facilities for fire suppression and/or to design compartments such that fire and smoke does not spread beyond the compartment of origin. Buildings must also be designed to allow safe and quick egress for its occupants during fires. Building safety objectives during fires is to (1) prevent collapse of the structure, (2) avoid fire and smoke spread beyond the compartment of origin. In order to prevent collapse of the structure, the structural framing system should comprise of noncombustible and fire resistive materials. Concrete is noncombustible and is able to resist elevated temperatures with only minor detriments in regard to its material properties. Structural steel, while a non-combustible material, loses rigidity and strength and experiences warping when exposed to prolonged high temperatures (Buyukozturk & Ulm, 2002). Such is the case that eventually led to the collapse of the WTC Towers (Ghoniem, 2002). Wood, which is also a typically building material, is mostly combustible, and is typically applied with proper treatment and protection against fire. Compartmentation also play a major role in building integrity. Failure in the compartment material causes fire to spread and may allow a bigger influx of oxygen, which then intensifies the fire.
2.2. Fire Risk Evaluation Methods There are four categories of fire risk evaluation methods (Watts & Hall, 2002): narratives, checklists, indexing, and probabilistic. Narratives only evaluate qualitatively by checking against established standards. This practice, however, is limited in the sense that it does not cover parameter requirements that vary case by case.
27 Checklists, on the other hand, contains all the prescribed requirements and checks if the building satisfies all the provisions. This is typically used in the implementation of prescriptive-based fire codes. Indexing method, also called point scheme model (Fraser-Mitchell, 1994), assigns indices as risk or risk factor quantifier, based on historical or heuristic judgment. This is a semi-quantitative method, fusing both quantitative and qualitative measures by assigning scores on qualitative indicators. Probabilistic method, a purely quantitative method, is the most comprehensive. It computes for the risk probabilities and expected values of outcomes that are then established from data, explicit assumptions and probabilities and mathematical relationships among factors. It also requires intensive data collection and computations. This research proposes a fire risk indexing system for buildings which can be benchmarked with respect to two established indexing systems, the Fire Safety Evaluation System of the NIST (1978) and the Risk Standardization Method for Assembly Occupancies in China developed by Han (2011). 2.2.1. FSES Risk Indexing for Health Care facilities (Nelson & Shibe, 1978) An evaluation system for health care buildings involving inpatients was formulated based on the requirements of the Life Safety Code of the National Fire Protection Association. In the development process, the Life Safety Code was analyzed and organized for subsequent review by professionals. Ratings were then established using Delphi method by a group consisting of fire protection engineers.
28 The system incorporates, patient characteristics such as age, mobility, density, as well as the ratio of patients to attendants, in the evaluation. Other factors checked are the existence of sprinklers and the fire zone. Fire zone relates to the problems with access of firefighters to the location of fire, particularly when the fire is at higher floors or in the basement. It also recognizes the difficulty in evacuation with increasing building height. 2.2.2. Risk Standardization Method for Assembly Occupancies (Han, 2011) Three main factors are identified as contributory to life safety in assembly occupancies: inherent fire hazard factors, fire control factors and evacuation factors. Under these three are secondary indicators, which also branch out into tertiary indicators. Fire Risk to Life Inherent Fire Hazard Factors
Fire Control Factors
Evacuation Factors
Building structure
Fire Protection Measures
Evacuation Facilities
Ignition sources
Fire Facilities
Personal Characteristics
Fire Load
Fire Management
Fire Rescue
Figure 12. Fire risk tree diagram by Han (2011)
29 Tertiary indicators are assigned a grade from 1 to 5, with 5 as the best state and 1 as the worst state. Risk score, R, is then computed as follows: = where I is the indicator score and W is the weight corresponding to the indicator. Computed risk scores were grouped into classes from I to V from worst state to best state. These risk scores were compared against insurance underwriting recommendations for verification.
2.3. Multi-hazard Framework The dynamics in fire risk is different from other disaster risks in the sense that the others are posed by inevitable natural hazards such as earthquakes, tsunamis, hurricanes and floods. Fire, in contrast, may arise from either natural, such as volcanic eruption, or anthropogenic actions. However unique it is, fire risk management should be incorporated in a multi-hazard framework as the risk management is neither mutually exclusive nor independent of another. US Federal Emergency Management Agency (FEMA) started a multi-hazard disaster risk analysis using the HEV framework with the goal of a unified building database analyzed for vulnerability to various hazards. In the Philippines, the groundwork for multi-hazard HEV approach to analyzing disaster risk has already been laid out by the works on the Greater Metro Manila Risk Assessment Project (GMMA RAP).
30 Hazards were analyzed by means of analytical models, exposure by means of field survey, and vulnerability of structures by means of combinations of computational, empirical and heuristic methods. Various methods were employed to develop the computational curves – pushover structural analysis for earthquakes, computational fluid dynamics approach for severe wind, and components-based estimation approach for flood vulnerability. The components-based estimation approach could be applied to fire vulnerability of structures.
31
3. Methodology 3.1. Identification of Key Building Features Relating to Fire Safety A thorough review of the provisions of the Revised Fire Code of the Philippines, R.A. 9514, was done to identify features and characteristics of a building that are regulated to ensure fire safety. This was coupled with ocular inspections and building plan reviews. Building features relating to fire safety were also identified through compilation and review of several published journal articles on building fire safety, fire risk assessment and performance-based criteria in fire safety design, as well as case studies and reports on fire incidences both local and abroad. A fire safety expert was interviewed in the person of Chief Inspector Alma Abacahin, Chief for Intelligence and Investigation at the Bureau of Fire Protection (BFP) Quezon City, in order to identify the various factors causing losses and fatalities in actual recent fires. Fire incidence reports and statistics by BFP were also analyzed for effects of building features to fire risk.
3.2. Development of a fire risk evaluation framework The identified building features were organized and associated into corresponding risk factors: hazard, exposure, and vulnerability, for both life risk and building risk due to fire. Other factors having impact on fire risk, such as those relating to occupants characteristics, situational conditions and the likes, were also identified through literature review, experts’ opinion and empirical analysis.
32 Measures of these factors, whether qualitative or quantitative, herein called indicators, were identified for inclusion in the checklist tool.
3.3. Development of a building survey tool for fire risk evaluation An evaluation tool for building fire safety was developed based on the Bureau of Fire Protection Checklist and an initial building survey tool for UP Academic Buildings developed by Ildesa (2013). Fire risk factors and sub-factors identified in the framework were incorporated into the checklist. All parameters currently being checked by the BFP were retained for completeness although reorganization of the contents was done to ensure compatibility with the framework and also to make the use of the checklist tool easier. Both paper and electronic versions of the tool were developed to promote wide use. Said checklist is to be used in conjunction to a fire load survey for a more detailed evaluation. For the purpose of this research, the tool used by Clavecilla (2013) in his survey of fire loads in UP Diliman buildings was used. The development of the survey tool was iterative as it was modified during the evaluation of UP Diliman buildings, in order to enhance ease of use.
3.4. Development of a fire risk index calculator An indexing system was developed for fire risk, both for life and building risk, as well as for the corresponding factors of hazard, exposure and vulnerability. States were assigned with numerical values from 1 to 5, 1 being the most preferable or ideal state and 5 being the least preferable or the worst state. A value of 3 corresponds to a minimum
33 acceptable condition and that an index numerically lower than 3 corresponds to an acceptable state while those higher corresponds to an unacceptable state. The same metric was also used in giving scores for the sub-factors and indicators. For every indicator, the ideal state was pegged at 1, barely acceptable conditions at 3 and worst conditions at 5. Values of 2 and 4 are also given as intermediate states. Judgment on the ideal states were based on pertinent literature, state of practice and actual conditions in the country in regard to fire safety in buildings. An interface was developed to facilitate the linking of the electronic fire safety checklist and the fire risk calculator using a spreadsheet software.
3.5. Evaluation of buildings in UP Diliman using the framework and tool Fifteen buildings were surveyed across UP Diliman. They consist of four assembly buildings, two libraries, five offices, three dormitories and one mixed occupancy as follows: 1. Bartlett Hall (College of Fine Arts) 2. College of Arts and Letters New Building 3. Institute of Mathematics Old Building 4. Melchor Hall (College of Engineering) 5. Gonzales Hall (Main Library) 6. UP Alumni Engineers Centennial Hall (College of Engineering Library 2) 7. Office of the University Registrar (OUR) 8. CMO – Community Affairs Building 9. Computational Science Research Center (CSRC) Building
34 10. Rizal Hall (Faculty Center) 11. Quezon Hall (South Wing) 12. Vinzons Hall 13. Albarracin Hall (Centennial Engineering Dormitory) 14. Kalayaan Residence Hall 15. Kamia Residence Hall Fire load densities (FLD) of compartments in these buildings were determined using a combination of inventory and direct weighing methods. Fire load densities in buildings were then determined by averaging the FLDs of at least three compartments in each building. The checklist was also applied on these fifteen buildings for fire safety evaluation. After which, the respective risk and risk factor indices were calculated using the developed risk calculator. This was followed by a qualitative analysis on the evaluated buildings in relation to the risk and risk factor indices generated by the calculator. Risk drivers for each of the buildings were analyzed and identified.
35
4. Results and Discussion 4.1. Key Building Parameters Contributing to Fire Risk In an interview with Chief Inspector Alma Abacahin, investigation and intelligence chief at the BFP Quezon City on May 25, 2013, she mentioned that fire risk is high in informal settlements, which is typically characterized by dense clustered houses, highly combustible construction and impenetrable alleys. She noted, however, that there are more casualties in fires on formal settlements because of entrapment. The risk is further escalated because the people are generally unaware of the standards for fire safety. Finally, she mentioned that even with the increase in funding for firefighting services, building quality deteriorates faster due to poor maintenance, making it more susceptible to fires. It can be concluded from the interview above that proximity to another structure, materials used, and accessibility of the structure to firefighters are factors contributing to fire risk. Specifically for life risk due to fire, the means of egress is reinforced as an important parameter. During a fire, the one that poses risk on the building is fire itself. As such, factors relating to the start of a fire and its propagation will have an effect on the building. In the case of the building occupants, three things pose danger: (1) direct exposure to flame and extreme temperature, (2) smoke and toxic gas inhalation, and (3) possible collapse of the building or its component that may severely injure or bury the occupant. As such, anything that will expose the occupants to any of the three or prevent him from avoiding such are considered hazardous. This also means that anything that hinders or impedes the egress of the occupants amplifies risk to life.
36 Table 5. Effect of building features on life and non-life risk. Effect on Effect on Building Feature Life Risk Building Risk Hazard brought about by contents (Fire Load) Building services equipment potential for fire Hazardous sectional use Potential external fire Structural framing material danger of building collapse, might danger of collapse injure or bury of the building occupant Compartment separations material (in)ability to contain fire in the compartment of origin, causing (or preventing) fire spread Building height ease or difficulty in egress from the building Automatic fire suppression features Standpipe system ease in fire extinguishing Accessibility of the building to firefighters Ventilation prevention of smoke & toxic gas Smoke control features exposure Egress means ease of egress from Lighting and signs the building Emergency evacuation plan Fire alarm system early warning for egress
4.2. FiRE! Framework: a Framework for Fire Risk Evaluation The identified factors are classified into risk factors in reference to the object of risk. All building features identified are classified as hazard to life as these are all external to the occupant. For the exposure factor, population density and duration of stay of the occupants are considered.
37
Figure 13. Detailed FiRE! Framework for Life Risk
38 Vulnerability of occupants is herein defined by the mobility and walking ability of the occupants, percentage of vulnerable populations such as differently-abled people, pregnant woman, children and elderlies. Capacity-related factors include the ability of the occupants for evacuation and firefighting. Capacity-related factors are coupled with vulnerability-related factors in this framework. Building materials and built-in fire suppression features are factors inherent to a building and hence, become classified as vulnerability-related factors when the building becomes the object of risk. For the scope of this framework’s applicability, building height becomes insubstantial in assessing the vulnerability of buildings, and as such, is decoupled from the building material subfactor. In regard to the fire load density, a portion of it comprising the fixed fire load reflects the combustible building features. This portion now becomes inherent to the element at risk (part of its vulnerability) which is why it is excluded from the Fire Load subfactor. Movable Fire Load, which reflects the combustible contents in a building is regarded as an indicator posing hazard to the building.
Figure 14. Detailed FiRE! Framework for Building Risk
39 Floor area and cost per square meter were identified as factors affecting the exposure of the building. Considering that the fire risk to buildings is measured in terms of events per square meter of building per year, the bigger the floor area of the building, the more exposed it is to the risk. Building cost per square meter, on the other hand, is a determinant in the expected value of the damage cost that could be attributed to fire risk.
4.3. FiRE Checklist FiRE Checklist was developed by incorporating the factors and indicators of the FiRE! Framework into the BFP Checklist. Major revisions include the addition of a detailed building occupant characterization, which forms Part II of the FiRE Checklist. Contents were also reorganized to match the framework and facilitate an easier conduct of survey. FiRE Checklist form Appendix A of this research paper. The developed tool is non-technical and inventorial in nature. This eliminates the required prior knowledge in the Fire Code, and enables use by non-specialists. This also reduces errors and bias in the evaluation since compliance to the code is implicitly checked by the tool. With the new building survey tool, surveys take around one to two hours, depending on the size of the building and the duration of interviews with building administrators. .
4.4. FiREcalc: Fire Risk Index Calculator Various states of the identified indicators were identified and scored based on how they compare with the existing standards and the pertinent qualities to ensure fire safety. The calculator was programmed using Microsoft Excel.
40 4.4.1. Sub-factors and indicators relating to Fire Risk to Life Sub-factors and indicators contributing to fire risk to life and their corresponding scoring systems are discussed subsequently. Fire Load Density The fire load indicator was measured in terms of the average fire load density in the building. Reference values were based on the range of available fire load data from published journals as well as the surveyed fire load densities in UP Diliman buildings. Table 6. FiREcalc Scores for Fire Load Density Score Fire Load Density MJ/m2 1 Less than 500 2 500 – less than 1000 3 1000 – less than 1500 4 1500 – less than 2000 5 2000 and above Ignition Sources Three major indicators of ignition sources were identified: building service equipment, hazardous sectional use and potential for external fire. Building Service Equipment Building service equipment are typical features and facilities of a building that might be essential or complementary to the operations within the building. Boilers for heating water, generators for continuous power supply, electrical installations, garbage handling facilities and the likes may pose risk. In the case of boilers and generators, the hazard pertains to the presence of large amounts of fuel that could be ignited. Permits are checked for fuel storage in compliance
41 with the law. Further, the hazard would be lowered if these hazardous equipment are properly separated and has fire protection. For garbage handling facilities, the presence of combustible materials in bulk and the generation of highly volatile and combustible gases necessitates that it be properly separated and provided with fire suppression features. Electrical installation is checked because it is present in almost every building and yet based on BFP data, it is the most common cause of fire accounting for 24% of the fires with determined causes. Electrical hazards are also noted for consideration.
Figure 15. Process flow diagram for FiREcalc: Building Service Equipment
42
Figure 15 shows the process flow in scoring the building service equipment in FiREcalc. Table 7 shows the equivalence of scores with conditions in the building. Score 1 3 5
Table 7. FiREcalc Scores for Building Service Equipment Description No unprotected hazardous building equipment and all necessary permits were secured Hazardous building equipment are present but with permits and proper separation Hazardous building equipment are present, unprotected and lacks necessary permits
Hazardous Sectional Use This pertains to sectional occupancies and compartment use within the building that may pose fire hazard. Included are laboratories, kitchens, laundry, storage and windowless basements. Corresponding separation and protective measures are checked. Process flow and qualitative descriptions of the scores are as follows: Score 1 2 3 4 5
Table 8. FiREcalc Scores for Hazardous Sectional Use Description No unprotected, unseparated hazardous areas within the building Hazardous areas with proper separation, most with proper fire protection Hazardous areas with proper separation, inadequate fire protection Hazardous areas without proper separation but with ample fire protection Hazardous areas exist without proper protection and separation
43
Figure 16. Process Flow Diagram for FiREcalc: Hazardous Sectional Use Potential for External Fire While the first two indicators are internal to the building, fires are also likely to be caught from a burning adjacent building. This is precisely why fires are common in areas with clustered structures. For this indicator, all structures in proximity to the building are identified and corresponding distances are measured. Nearby hazardous structures are also marked as these amplify the hazard to a building.
44 For buildings adjacent to the property line, compliance to fire wall requirements is also checked. Following is the process flow diagram and the scoring equivalents for this fire hazard indicator
Figure 17. Process Flow Diagram for FiREcalc: Potential External Fire Score 1 2 3 4 5
Table 9. FiREcalc Scores for Potential External Fire Description Building is sufficiently far from any structure Building is sufficiently far from any hazardous structure and it fully complies with the fire wall requirement Building in close proximity to another structure but fully complies with the fire wall requirement Building is in close proximity to a nonhazardous structure but does not satisfy fire wall requirements Building is in close proximity to a hazardous structure and does not satisfy fire wall requirements
Building Material and Building Size This sub-factor consists of three indicators namely: structural framing material, compartment separation material and building height.
45 Structural Framing Material Structural framing material refers to the fire resistance and combustibility of materials used for the structural elements such as beams, columns, roof trusses, shear walls and diaphragms, failure of which may lead to building collapse or a portion of it.
Figure 18. Process Flow Diagram for FiREcalc: Structural Framing Material Score 1 2 3 4 5
Table 10. FiREcalc Scores for Structural Framing Description Framing is entirely concrete and/or protected steel Framing is mostly concrete, partly unprotected steel Framing is mostly concrete and partly wooden Framing is unprotected steel Framing material is predominantly combustible
Generally, concrete and materials with similar fire-resistive characteristics are preferred for the structural framing. Steel with proper protective measures is also capable
46 of resisting high temperatures. Unprotected steel, however, may warp with increasing temperature and melt with large temperature increase. Combustible framing is the least preferable when it comes to ensuring that the structure will not collapse under fire. Compartment Separation Material Compartment separation material refers to the fire resistance and combustibility of materials used for compartment separations. This reflects the containment of a potential fire to its compartment origin so as not to spread through the entire building. This indicator also considers other contiguous fixed building features such as ceilings and floor finish.
Figure 19. Process Flow Diagram for FiREcalc: Compartment Separation
47 Table 11. FiREcalc Scores for Compartment Separation Score Description 1 Compartment separation and contiguous components are totally fire resistive 2 Compartment separation and contiguous components are mostly fire resistive 3 Walls and partitions are totally fire resistive 4 Some walls and partitions are non-fire resistive 5 Compartment separation is non- fire resistive Building Height Building height is measured in terms of the number of storeys. In principle, the higher the building, the more difficult it is to evacuate out of the building posing hazard to life. Single-level buildings take a score of 1, while buildings classified as high-rise under the UP ICE Building Typology (2013), i.e. those with more than seven storeys, takes a score of 5. Table 12. FiREcalc Scores for Building Height Score Description 1 Single-storey building 2 Two-storey building 3 Midrise Building (3-5 storeys) 4 Midrise Building (5-7 storeys) 5 High-rise (more than 7 storeys) Fire Suppression Features Indicators considered here include the presence of an automatic fire suppression systems (AFSS) and standpipe system. Accessibility of the building to firefighters is also checked in parallel.
48 Fire Suppression Systems This includes the presence of an automatic fire suppression system (AFSS) and/or a standpipe system, building features that are instrumental in extinguishing fires. Documentation, testing and monitoring of these features to ensure working conditions are also considered in this indicator.
Figure 20. Process Flow Diagram for FiREcalc: Built-in Fire Suppression System Score 1 2 3 4 5
Table 13. FiREcalc Scores for Fire Suppression Systems Description AFSS is installed, is well documented and amply tested AFSS is installed and meets standards Standpipe system present, in good condition and well documented Standpipe system present but not well monitored and documented No automatic fire suppression system
49 Accessibility of Building to Firefighters This parameter considers distance of the building to the nearest fire station as well as the condition of access roads and the presence of fire lane.
Figure 21. Process Flow Diagram for FiREcalc: Accessibility to Firefighters Table 14. FiREcalc Scores for Distance from Fire Station (Han, 2011) Score Description 1 Building is within 6 km from a fire station 3 Building is between 6-10 km from a fire station 5 Building is more than 10 km from a fire station Scores generated for the distance from the fire station and the provision of fire lanes are averaged. The result is then averaged with the score generated for the presence of fire suppression systems in the building to arrive at the indicator score.
50 Smoke Control and Ventilation Ventilation The ideal condition is that all rooms are properly ventilated. When most rooms are not properly ventilated, it poses serious hazard on the occupants. Table 15. FiREcalc Scores for Ventilation Score Description 1 All rooms are well ventilated 3 Most rooms are well ventilated 5 Most of the rooms are not well ventilated Smoke Protection
Figure 22. Process Flow Diagram for FiREcalc: Smoke Protection Toxic gas and smoke is prevented from spreading by ensuring that vertical openings such as elevators shafts and garbage chutes, as well as pipe chases, are well-
51 protected. Fire doors in good condition and doors having self-closing mechanism also prevent horizontal smoke spread. Score 1 3 5
Table 16. FiREcalc Scores for Smoke Protection Description Smoke propagation via horizontal and vertical openings is sufficiently prevented Some openings are not properly protected There are no control measures to prevent propagation of smoke
Egress Features Egress features consider various building features that a building occupant may have to pass through from the inside to the outside of a building during evacuation. Building Exit Door Width, location and accessibility of the building’s main exit door is checked. Main exit door should also allow quick and easy egress from the building.
Figure 23. Process Flow Diagram for FiREcalc: Building Exit Door
52 Score 1 3 5
Table 17. FiREcalc Scores for Building Exit Door Description Width of exit sufficient, accessible and easily opens in the direction of egress Width and distance of main exit is qualified but poses difficulty in egress Main exit is non-compliant with the standards
Corridors, Hallways and Floor Exits These building features should allow a quick and unobstructed access to the main exit door from various points in the building. Width of corridors is checked along possible obstructions and adequacy of illumination. Presence of dead ends that may trap escaping occupants is also quantified and noted. Number of exits per floor is also checked for sufficiency. There should be at least two per occupied floor.
Figure 24. Process Flow Diagram for FiREcalc: Corridors and Floor Exits Score 1 3 5
Table 18. FiREcalc Scores for Corridors, Hallways and Floor Exits Description Exit paths are sufficiently wide and unobstructed, all floors have adequate exits Exit paths are sufficiently wide but with minor obstructions, floors have adequate exits Exits paths are narrow, floor exits lacking
53 Room and Intermediate Exits Ease of egress of the occupants from any room or compartment in the building. Specifically, the following conditions are checked: accessibility, obstructions, ease of opening, direction of door swing, and in the case of big rooms or compartments (e.g. mezzanine), the sufficiency of the egress provisions and conditions. Table 19. FiREcalc Scores for Room and Intermediate Egress Score Description 1 All rooms comply with code provisions for egress 3 Most rooms comply with code provisions for egress, with minor non-compliance 5 Many rooms do not comply with room egress provisions in the code Stairways All provisions pertaining to vertical exits are included in this indicator. Width of the stairways, proximity to the main exit door, as well as provision of fire escapes as means for alternative egress.
Score 1 3 5
Table 20. FiREcalc Scores for Stairways Description Stairways are fully compliant with the code Stairways are adequate for egress but with minor obstructions Stairways are inadequate in size and number
Area of Safe Refuge This indicator checks if safe refuge areas are provided inside the building. Such areas should properly enclosed. Scoring is quite different in the case of this indicator,
54 with 3 as the lowest possible score. This was assigned in the context that areas of safe refuge are good to have but are not necessarily hazardous in its absence.
Figure 25. Process Flow Diagram for FiREcalc: Area of Safe Refuge Table 21. FiREcalc Scores for Areas of Safe Refuge Score Description 1 Areas of safe refuge are provided within the building and complies with the code 2 Areas of safe refuge are provided within the building with minor inadequacies 3 Areas of safe refuge are not provided Emergency Egress Aids These are features, other than the physical pathways, that affect the ease of evacuation egress of occupants from the building during a fire. It includes emergency lights, emergency evacuation plan, exit and warning signs, and alarm system. Emergency Lights This indicator checks for the presence of automatic emergency lights that are sufficient, well maintained, tested and ensured operational.
55
Figure 26. Process Flow Diagram for FiREcalc: Automatic Emergency Lights Score 1 3 5
Table 22. FiREcalc Scores for Emergency Lights Description Automatic emergency lights are provided, adequate and tested regularly Automatic emergency lights are provided but with minor inadequacies Automatic emergency lighting system is not provided or substantially lacking
Emergency Evacuation Plan Adequacy and visibility of building emergency evacuation plans are checked for compliance with the Fire Code.
Figure 27. Process Flow Diagram for FiREcalc: Emergency Evacuation Plan
56 Table 23. FiREcalc Scores for Emergency Evacuation Plan Score Description 1 Emergency evacuation plans are posted in rooms and hallways and are easy to read 3 Emergency evacuation plans are posted in various parts of the building 5 The building has no emergency evacuation plan Exit Signs Exit and warning signs are also checked for adequacy and visibility. The width and height of the exit sign, and its illumination and visibility are all checked in regard to their conformance with Fire Code Provisions.
Figure 28. Process Flow Diagram for FiREcalc: Exit Signs Score 1 3 5
Table 24. FiREcalc Scores for Exit Signs Description Exit signs are adequate and fully code compliant Exit signs are present with minor inadequacies Exit signs are absent or substantially lacking
57 Alarm System Ideally, buildings should have an automatic, centralized, accessible and regularly checked and monitored. Warning sound should be sufficiently loud to be heard at all parts of the building.
Figure 29. Process Flow Diagram for FiREcalc: Alarm System Score 1 2 3 4 5
Table 25. FiREcalc Scores for Alarm System Description Fire alarm is automatic, centralized, adequate and regularly monitored Fire alarm is automatic, adequate but not regularly monitored Manual fire alarm; covers the entire building Fire alarm is present but does not cover the entire building There is no reliable alarm mechanism
Population Density of Occupants The quantity of exposed population is measured in terms of the occupants to floor area ratio at the peak time of occupancy, R. Values are compared against the ratios prescribed by Han (2011) as follows: Table 26. FiREcalc Scores for Population Density Score R 1 0 2 0.2 3 0.5 4 1 5 2
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Duration of Stay Exposure factor for life risk is also measured in terms of the occupants’ typical duration of stay in the building. Score 1 3 5
Table 27. FiREcalc Scores for Duration of Stay Description Occupancy is predominantly transient Average duration of occupancy is approximately 8 hours Average duration of occupancy is more than 8 hours
Alternatively, in the absence of data on average duration of occupancy in the building, the occupancy type may be used as proxy. For example, assembly and storage occupancies are predominantly transient; offices are occupied for approximately eight hours; for residential buildings, occupants typically stay for more than eight hours. Mobility and Walking Ability Vulnerability of occupants is measured in terms of the percentage of vulnerable population in the building. Vulnerable population defined herein includes differentlyabled people, pregnant woman, children below 10 years of age and elderly people above the age of 65. The scoring, as proposed in this research, is as follows: Table 28. FiREcalc Scores for Mobility and Walking Ability Score Ratio of vulnerable population 1 0 2 0.1 3 0.2 4 0.5 5 1
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In the ideal state, there would be a lot more mobile occupants compared to the vulnerable ones. In the other end of the spectrum, when the number of vulnerable occupants exceed the mobile ones, as in the case of healthcare facilities, it would be very difficult to have everyone evacuated. Alertness of Occupants The state of the occupants stay in the building also affect their vulnerability. In essence, one who is asleep at the onset of fire would be more vulnerable as compared to someone who is in alert, or even agile, state when the fire starts. Scores are as follows: Score 1 3 5
Table 29. FiREcalc Scores for Alertness of Occupants Description Occupants are predominantly in their AGILE and ALERT state during their stay Occupants are predominantly in their ALERT state during their stay Occupants engage in INACTIVE stay (e.g. sleeping) inside the building
Efforts to decrease the vulnerability of occupants are herein classified as capacityrelated factors. This includes fire evacuation training and drills, firefighting training and fire brigades, and access to firefighting and escape equipment. Fire Evacuation Training and Drills The frequency of the fire safety trainings and drills participated in by the occupants is checked, along with fire safety instruction given to new occupants.
60 Table 30. FiREcalc Scores for Fire Evacuation Training and Drills Score Description 1 Evacuation drills conducted regularly, occupants are given adequate fire safety instruction 3 Fire drills are conducted but without refresher 5 Occupants have no fire safety training Firefighting Training and Fire Brigades Occupants training for firefighting, organization into fire brigades and the presence of a fire safety program under the supervision of the Bureau of Fire Protection are checked. Table 31. FiREcalc Scores for Firefighting Training and Fire Brigades Score Description 1 There is a BFP-trained organized fire brigade among the occupants 3 There is an organized fire brigade among the occupants 5 There is no fire brigade organization among the occupants Access to Firefighting and Escape Equipment This parameter includes the availability, adequacy and accessibility of properly maintained portable fire extinguishers (PFE). Escape accessories available in the fire hose cabinet are also checked. Table 32. FiREcalc Scores for Access to Firefighting and Escape Equipment Score Description 1 Occupants are equipped with firefighting tools that are accessible and well-maintained 3 Required number of portable fire extinguishers is provided 5 Firefighting and escape equipment are unavailable or substantially lacking
61 4.4.2. Other Sub-factors and indicators relating to building risk The shift in the object of risk makes the scoring of the indicators different as compared to that in life risk. Ignition sources and built-in fire suppression features are scored in the same manner as in the life risk part. Following is a discussion on what changed from the indexing for life risk to building risk indexing. Movable Fire Load Movable fire load was used instead of the total fire load for the purpose of building risk indexing in the hazard part. Fixed fire load was excluded because it consists of the combustible portions of the building. If the building features are combustible, the more susceptible it is to a fire. By this definition the fixed fire load now forms part of the building’s vulnerability. In contrast, movable fire load can be seen as external to the character set of a building. As a hazard, it may be consciously diminished to reduce building risk. Table 33. FiREcalc Scores for Movable Fire Load Density Scores Score Fire Load MJ/m2 1 0 2 200 3 600 4 1000 5 1500 Building Materials Building height is now excluded from this subfactor. Structural framing and compartment separation is scored in the same manner as in life risk.
62 Floor Area The bigger the floor area, the higher the exposure. Scores are given as follows: Table 34. FiREcalc Scores for Floor Area Score Area (sq m) 1 0 2 500 3 2000 4 5000 5 10000 Cost Per Square Meter of the Building The cost of the probable building damage due to fire is also proportional to the cost of the building. Building finished is checked and classified as either low cost, middleclass or high-end and is assigned with the following scores: Table 35. FiREcalc Scores for Cost per Square Meter Score Description 1 Low cost structure (e.g. agricultural, stadium) 3 Structure has middle class finish 5 High end structure In the presence of data on the actual cost of the structure per square meter, it is proposed that the cost be compared to the average construction cost in the country, including the cost of finishes. Those falling within one standard deviation from the average per square meter cost are assigned a score of 3, those above a score of 5, and those below a score of 1.
63 4.4.3. Weights of the indicators and sub-factors All attributes, in all levels (indicator, sub-factor and factor) are assumed to be of equal weights in this study. Provisions for varied indicator and subfactor weights, however, have been incorporated into the FiREcalc so that it will be usable should it be proven that some attributes have relatively greater contribution to fire risk than others. 4.4.4. Calculation of the Fire Risk Indices From the indicator level to the sub-factor level to the factor (HEV) level, index is computed by simple averaging. In the presence of weights, weighted averaging is done. The following equation is used in the computation of hazard, exposure and vulnerability indices: = Where
I is the indicator score W is the corresponding additive weighting factor
Fire risk index, on the other hand, is computed by getting the geometric mean of the hazard, exposure and vulnerability indices. The use of geometric mean, as opposed to the arithmetic mean, is consequential to the definition of risk as product of hazard, exposure and vulnerability. Risk index, R, is then computed as follows: = √ × Where
H is the hazard index E is the exposure index V is the vulnerability index
×
64 4.4.5. Risk Equivalence of the Fire Risk Indices Risk and risk factor indices follow the same convention as the scores, where 1 corresponds to the best condition, i.e. lowest risk level, and 5 corresponds to the highest risk level. Index values can be interpreted as follows: Table 36. FiREcalc risk index descriptions Risk Description Index 1 Highest safety level 2 High safety level 3 Minimum safety level 4 High risk level 5 Highest risk level Alternatively, these indices can be expressed in terms of acceptable and maximum tolerable risks, and the average fire risk in the country. This research proposes the following correspondence: Life Risk proposed equivalence Table 37. FiREcalc alternative life risk index equivalence (proposed) Risk Probability of death in a year Index 1 1x10-6 (1 micromort) 2 2 micromorts 3 5 micromorts 4 10 micromorts 5 1x10-4 (100 micromorts) or greater One micromort (1x10-6 probability of mortality) gives the condition at which no further improvement in safety is necessary (Hunter & Fewtrell, 2001). This level of life risk is more or less equivalent to the risk of dying by electrocution at one’s own home (RCEP, 1998). This corresponds to a risk index of 1.
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WHO sets the maximum tolerable risk to any individual member of the public at 100 micromorts (10-4) (Hunter & Fewtrell, 2001). This is approximately the likelihood of an individual dying in a vehicular accident (RCEP, 1998). This is proposed in this study to be equivalent to risk index 5. It means that when the fire risk to life in buildings exceeds that of the risk of figuring in a vehicular accident, that condition would not be acceptable. In Metro Manila, where 77% of the fire incidences occur (Velasco, 2013) and most of the target buildings of this tool are situated, the average annual fire risk to life from 2007-2012 is 5 micromorts. This is associated with risk index 3. In the evaluation of the fire risk based on building features, minimum compliance to the code is assigned a score of 3. It means that for buildings compliant to the standards set by the Fire Code, the residual life risk is 5 micromorts. The average annual fire risk to life in the country as computed from the 2005-2012 BFP records is approximately 2 micromorts. This is associated with risk index 2. The highest life risk due to fire computed in the country, also from BFP data, on a municipality or city level, is 18 micromorts, which is basically in the order of magnitude of 10-5, which is hereby associated with risk index 4. Building Risk proposed equivalence A new term is proposed in expressing a measure of building risk: microcas. This is derived from the prefix micro, which means 1 in a million, and the Latin word casus, which means an event or an incident. 1 microcas is equal to 1 fire event per square meter floor area of building.
66 Table 38. FiREcalc alternative building risk index equivalence (proposed) Risk Annual building risk Index (fire event/ m2-year) 1 1(10-7) or 0.1 microcas 2 1(10-6) or 1 microcas 3 2(10-6) or 2 microcas 4 5(10-6) or 5 microcas 5 1(10-5) or 10 microcas The average occurrence of building fires in the Philippines is 3.6(10-7) per square meter of building per year based on statistics from 2010-2012. The risk is higher in Metro Manila at 1.7(10-6) / sq.m.-year, approximately 2 microcas. The average building risk in Metro Manila, where most buildings within the applicability of the tool are located, is taken as the equivalent of median risk index 3. This is the residual risk amid compliance with the fire code. Other risk index equivalents are taken in reference to the median risk index. Risk index 2 is assigned to be equivalent to 1 microcas, while risk index 1 is taken as equivalent to one order of magnitude lower at 0.1 microcas. This is in the same order of magnitude as the national average building risk. Risk index 4 is taken as equivalent to 5 microcas and an index of 5 is an order of magnitude from index 3 at 10 microcas.
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4.6. Evaluation of UP Diliman buildings using FiREcalc Fifteen buildings in UP Diliman were surveyed for fire loads and assessed using the FiRE Checklist from January to June 2013. The risk and risk factor indices were calculated using FiREcalc. In regard to life risk, three dormitories figured with the highest risk indices, Kamia Residence Hall with 3.05, Kalayaan Residence Hall with 2.85, and Albarracin Hall with 2.80. Vulnerability is the main risk driver in the case of these three buildings. The difference in the duration of stay of people, which is typically prolonged in residence halls as compared to offices and academic buildings, and in the nature of occupancy, as these buildings are occupied by people in non-alert state (e.g. sleeping). Table 39. Life risk and risk factor indices for 15 buildings in UP Diliman Building R H E V Albarracin Hall 2.80 2.00 3.00 3.67 Bartlett Hall 2.05 2.71 1.00 3.17 CAL New Building 2.12 2.71 1.00 3.50 CMO Community Affairs Building 2.49 2.43 2.00 3.17 CSRC Building 1.97 2.71 1.00 2.83 Engineering Library 2 1.67 1.86 1.00 2.50 Faculty Center 2.62 2.57 2.00 3.50 Kalayaan Residence Hall 2.84 2.29 3.00 3.33 Kamia Residence Hall 3.05 2.57 3.00 3.67 Main Library 2.08 2.86 1.00 3.17 Math Building 2.04 2.43 1.00 3.50 Melchor Hall 2.13 2.57 1.50 2.50 Office of the University Registrar 1.97 2.71 1.00 2.83 Quezon Hall 2.49 2.43 2.00 3.17 Vinzons Hall 2.53 2.57 2.00 3.17 Engineering Library II with a life risk index of 1.67, Office of the University Registrar and Computational Science Research Center, both with life risk index of 1.97 got the three best conditions for life safety. This is attributable to the relatively low
68 vulnerability of occupants in these buildings because of the ease of access to fire safety and escape equipment. The shorter average stay of occupants in these buildings, mostly transients, is another determinant in this low life risk level. Notable are the high vulnerability indices for all buildings. The lowest (best case) obtained vulnerability index for life risk is 2.50, in the case of Melchor Hall and Engineering Library II, both of which have recently conducted fire safety drills. While the occupants of every building in UP Diliman are mostly mobile and ablebodied, the high vulnerability is brought about by the lack of training and education in fire safety, as well as the lack of organization in anticipation of a fire event. Computed life risk indices are mostly between 2 and 3. Hazard indices for the surveyed buildings are also clustered between 2 and 3. Risk, hazard, exposure and vulnerability indices were also computed with the building as the object of risk using FiREcalc. Results are as follows: Table 40. Building risk and risk factor indices for 15 buildings in UP Diliman Building R H E V Albarracin Hall 2.32 2.00 2.50 2.50 Bartlett Hall 2.60 2.00 2.50 3.50 CAL New Building 2.19 1.50 3.50 2.00 CMO Community Affairs Building 2.24 1.50 2.50 3.00 CSRC Building 2.29 2.00 3.00 2.00 Engineering Library 2 1.99 1.50 3.50 1.50 Faculty Center 3.13 2.50 3.50 3.50 Kalayaan Residence Hall 2.66 2.50 3.00 2.50 Kamia Residence Hall 2.66 2.50 3.00 2.50 Main Library 3.11 3.00 4.00 2.50 Math Building 2.60 2.00 3.50 2.50 Melchor Hall 2.47 1.50 4.00 2.50 Office of the University Registrar 2.82 3.00 3.00 2.50 Quezon Hall 2.24 1.50 3.00 2.50 Vinzons Hall 2.51 1.50 3.00 3.50
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Three buildings with the highest calculated risk indices are Faculty Center (Bulwagang Rizal), Main Library (Gonzales Hall) and the Office of the University Registrar (OUR), with risk indices 3.13, 3.11 and 2.82 respectively. The high risk index for Faculty Center is primarily due to its vulnerable construction. It has highly combustible partitions and finishes. The building also has the highest fire load density among those surveyed. Main Library also has a high level of fire load in it and this is one of the factors why the risk index is high. The sheer size of the building, at 12,000 square meters is also a determinant giving it a high exposure index. Office of the University Registrar comes in at third also because of the amount of combustible materials stored in it, and also because of the presence of an unprotected generator set which poses hazard on the building. CAL New Building and Melchor Hall, on the other hand, shows how the risk factors are balanced to lessen the risk. The exposure factor is unmanageable because it consists of the floor area covered by the building, as well as the cost per square meter. While the two indicators cannot be managed, risk can be reduced by diminishing the hazards that may start a fire, and also by ensuring that the building will be able to withstand a fire, in case it occurs. Considering the spread of the risk index results, most of the building risk indices are clustered between 2 and 3. With the exception of Faculty Center and Main Library, the buildings are generally on the safe side against fire.
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4.7. Calibration methods for FiREcalc FiREcalc is designed such that it is easily calibratable provided that there is sufficiency in the data. The tool evaluates risk on a building scale. Statistical data on fire risk, however, are generated on a community-level. These two can be bridged by evaluating the population comprising a community (e.g. barangay, city or province) and successively comparing the average calculated risk with the available statistical data. Given an ample population of buildings evaluated using FiREcalc in the long run, fire risk can be calculated from the fire occurrences in the population of prior-evaluated buildings. This then can be referenced against the risk level generated by the tool. The tool can be fine-tuned through various heuristic methods such as the Delphi Method. This obtains experts’ judgment following a three-step procedure: anonymous response, controlled feedback, and statistical analysis of the responses. This method varies from a simple consensus development among a group of experts in the sense that it seeks to preserve the integrity of individual judgments by eliminating the factors of domination by influence. A Delphi group may be formed consisting of structural engineers and designers, fire protection engineers, safety practitioners, fire investigators, architects, and building administrators. The weights attributed to the factors, subfactors and indicators could be generated heuristically by means of Analytic Hierarchy Process (AHP), or empirically by extracting the different parameters in fire incident reports and correlating each one with the resulting fire risk.
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5. Summary and Recommendations 5.1. Summary and Conclusion A framework for evaluating fire risk in buildings, FiRE! Framework, was developed for both life risk and building risk, considering parameters which includes structural and nonstructural building features, occupants characteristics, and other factors, in the paradigm of the hazard-exposure-vulnerability model. Elements in the framework were incorporated and subsequently organized into a building survey tool, the FiRE Checklist. A risk indexing system and tool, FiREcalc, was developed based on the FiRE! Framework. FiREcalc incorporates quantitative and qualitative indicators of risk extracted from the FiRE Checklist to calculate an index that would numerically represent the level of risk. The tool returns an index from 1 to 5, with 1 as the most preferable state and 5 the least. The tool was applied to 15 buildings in UP Diliman consisting of dormitory, office, educational and assembly buildings. Results for life risk and building risk indices can be seen in Table 41. Dormitory buildings figured with the highest life risk indices while Engineering Library II, CSRC Building and Office of the University Registrar registered the lowest calculated risk indices. Faculty Center, along with Main Library and OUR, buildings with huge amounts of fire load figured with the highest building risks.
72 Table 41. Summary of Life Risk and Building Risk Indices for the surveyed UP Diliman Buildings Building Life Risk Building Risk Index Index Albarracin Hall 2.80 2.32 Bartlett Hall 2.05 2.60 CAL New Building 2.12 2.19 CMO Community Affairs Building 2.49 2.24 CSRC Building 1.97 2.29 Engineering Library 2 1.67 1.99 Faculty Center 2.62 3.13 Kalayaan Residence Hall 2.84 2.66 Kamia Residence Hall 3.05 2.66 Main Library 2.08 3.11 Math Building 2.04 2.60 Melchor Hall 2.13 2.47 Office of the University Registrar 1.97 2.82 Quezon Hall 2.49 2.24 Vinzons Hall 2.53 2.51 FiRE! Framework demonstrates usefulness in risk reduction and management by surfacing the risk drivers, factors that highly contribute to the risk. High life risk in the dormitories surveyed points to the nature and duration of occupancy. High building risk in Faculty Center, Main Library and OUR can be attributed to their high fire load densities. Equivalence between FiREcalc-derived risk indices and risk probabilities was proposed based on Philippine fire statistics and international standards. A unit of measure for building risk, microcas, which is equivalent to 10-6 fire events / m, was introduced. Life risk indices computed for the surveyed buildings fell mostly between 2 and 3. This is equivalent to 2 to 5 micromorts across the surveyed buildings. Similarly, calculated building risk indices fall in the same range for most of the 15 buildings. This corresponds to a building risk of 1 to 2 microcas.
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5.2. Recommendations for Future Work A framework is always a work in progress. As such, the FiRE! Framework can be improved through a comprehensive, exhaustive and repeated calibration. FiREcalc can be repeatedly calibrated by means of the methods presented in Section 4.7 of this research paper. Additionally, the interrelation of risk and risk factors may be derived to determine the weights that each one carries. These correlations may be derived empirically from fire incidence statistics, from heuristic judgments, and from computational models. FiREcalc risk index equivalents may be compared against those derived from purely quantitative risk evaluation approach. Also for further study is the exhaustive identification of other parameters affecting fire risk to people and buildings. This may be done through an extensive review, a detailed epidemiological assessment, of historical fire data coupled with statistical analysis to check for interrelationships among parameters. FiRE Checklist may be improved and optimized by conducting time studies on the conduct of fire safety inspections, and correspondingly introducing modifications that would optimize the accomplishment of the checklist form. An interface for the electronic version of the checklist, and the integration with the FiREcalc tool, will improve the ease of use. Computer or android application may be developed for ease of deployment.
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