【 Weak current College 】 performance of a risk analysis of building fire

Summary: for our country's use of existing architectural design fire protection standard, and a series of specifications for building a fire risk analysis of shortcomings that contains performance of fire risk analysis methods, and properties of fire risk analysis methods, established the basic framework of fire scenario some independent numeric range, determine methods of fire scenario. Thus the building fire safety risks provides an acceptable solution, at the quantitative approach, based on the understanding of the risk, achieve it acceptable risk level.
Keywords: building fire; risk analysis; risk
1 building fire risk analysis of the significance of
Fire risk analysis is the study of fire science. It is a judgment meets specifications. Include not only the risk of property loss, also contain life risks. Due to an acceptable level of risk is through people's attitudes to reflect. Therefore, it is changing, with uncertainty. There is a risk to life and property risk acceptable level is different. Life risk cannot simply use a metric to measure, but must take into account the value of human life, using people's attitude towards risk and risk probability identify building fire risk better reflect fire accident consequences that may occur. In recent years, the building features complicated and the emergence of new technologies, and also brought in some new risks, new hazards, there are different types of risk issues have different reactions, because people risk perceptions, on the current architectural design fire protection standard also had a certain impact. For example: because dance installstion fire, and on the architectural design fire protection standard law be modified to adapt to new social requirements.
2 two performance of fire risk analysis method
Fire risk analysis approach is performance-based design of the important evaluation criteria, nowadays, there are more sophisticated methods of BCA architecture Australia and United States building fire safety analysis methods (BFSEM: T), etc.
2.1 Australia BCA structure system of
Australia's BCA structure system of risk assessment model CWSARE-RISK is a quantifying performance of the building fire safety risk assessment models. Its characteristic is that the use of multiple fault tree set fire scenario, each scene has a probability, and each scene of the fire and smoke flow models have a connection with the reality of certainty, and each case is linked to a person's behavior and fire brigade rescue and response model.
2.1.1 Australia of BCA structure system includes nine sections
A volume, the General rules. Including A0, BCA, together with a description of the overall and the method of application to the relevant provisions; part A1, interpretation, explanation of the related words; A2, acceptable design and construction programmes, including the appropriateness of building materials, could prove suitability of evidence, the fire resistance of building components and early danger index; A3 building category. Provides for the classification of buildings, classified by standard and taking into account the situation of the subject class. The section under construction-design and construction, for the purposes of the building is divided into 10 categories.
B volume, part of the building structure. First of all give this volume describes the objectives, functions, properties, and then give this volume approved safety performance requirements, which are given on the building should meet, building material corresponding to the load requirements of the structure.
C volume, part of the fire performance. First of all give this volume describes the objectives, functions, performance requirements, which correspond to different content to a recognized security provisions, C1 section on fire resistance and thermal stability requirements; C2 section on fire partitioning and isolation; C3 section on opening protection requirements. Give some details of the content you want, such as fire resistance rating of external walls of fire characteristics, requirements, etc.
D volume, channel export section. First of all give this volume describes the objectives, functions, properties, and then tap contents gives recognition of security requirements, set for building D1 escape; D2 for the various types of export of construction requirements; D3 is set to disabled facilities. Subsequently, presents on the stairs, slopes and at the request of the escalators.
E volume, public facilities and equipment part. Correspond to different content to a target, the functional description, performance requirements and approved security provisions and conditions. E1 is on fire-fighting equipment requirements; E2 for elevator installations; E3 for emergency lighting, exit signage and alarm systems.
F volume, health and comfort. Correspond to different content to a target, the functional description, performance requirements and approved security provisions and conditions. F1 to the room humidity degree and weatherproof structure part; F2 as on plumbing fixtures and other equipment requirements; F3 as room size requirements; F4 on the part of the General lighting and ventilation requirements; F5 soundproofed for on and sound delivery requirements.
G volume, accessibility requirements. Correspond to different content to a target, the functional description, performance requirements and approved security provisions and conditions. G1 to smaller components and components requirements, primarily for swimming pool, air-conditioned vault and cellar; G2 on heating equipment, fireplaces, chimneys and ventilation tube; G3 to the construction requirements of the Atrium; G4 to the building of high requirements of the regional sections; G5 for forest fire occurred on a trend in the region.
H volumes, special-purpose buildings. Mainly on theatre, stage and public from the aggregation of the Hall to call. This one is divided into fire partitions, the stage wall structure, seating, stage and export of several parts.
I volume, maintenance section. First of all give this volume describes the objectives, functions, properties, and then give the accreditation provisions of security. Including the installation of security, mechanical ventilation and heating systems in several fields.
2.1.2 performance-based design standard architecture
BCA structural system in the overall interests of completely from a performance requirement, depending on the performance of the different aspects of the Division of different volumes for discussion; from the structure, fully embodies the BCAA performance-based design features, the body is divided into four volumes, goals, most of the functional description, performance requirements and accreditation of security requirements. In assessing your design, BCA manner on the one hand, a more flexible, it gives some performance indicators for designers and evaluation by reference, at the same time, also gives some acceptable evaluation programme. This becomes more flexible, more reasonable.
2.2 United States fire analysis method BFSEM
BFSEM method is that all architectural space and a combination of separate pieces. Carried out for the specific building fire performance analysis should clearly identify the space-separated parts system. While the fire itself is divided in different speeds and different ways to influence the architecture, people, and all kinds of objects in two parts: fire/heat and smoke. BFSEM method to assess building performance mainly includes the following five aspects: (1) prevention of fires; (2) the flame/thermal analysis (buildings through active and passive fire protection measures in its space and every other thing); (3) smoke/gas analysis (buildings remain selected space survival conditions stipulated time capacity); (4) structural analysis framework (framework for restricted fire avoid unacceptable distortion of collapse); (5) the movement of persons (people in the building flows or reach a safe place the requested time). In the assessment process, the possibility for the burning, the fire space fire expansion possibilities, a performance, the fire spread to the fire in the space, staff security, and other parameters, users can be specified based on experience and engineering judgment of subjective probability, or based on statistical data, it is estimated that each event occurred. BFSEM provides a way to identify the impact of fire performance factors. But its OK when various assessment parameters there is considerable uncertainty.
3 performance of fire risk analysis method of the base frame
Fire safety risk assessment to performance-based design method for background, considering the performance of building security in all its aspects (including fire and combustion products of creation and development of mobile products, fire, the fire to spread outside of the fire room, fire-fighting facilities for fire detection, fire-fighting, evacuation started with relief and other links), by setting the fire scene, the safety of personnel, the fire resistance of building structure and property losses, target results are unpredictable, and performance-based safety standards, specifications, instructions, safety standards, supplemented, on the building of the safety performance standards for integrated assessment, so as to provide a basis for architectural design decisions.
3.1 performance of fire risk analysis method of the base frame
Performance of fire risk assessment method of the base frame is made up of three parts. Namely: (1) integrated assessment; (2) data integration; predicting (3) characters.
3.1.1 integrated assessment
(1) identify evaluation goals and functional requirements. According to the specific characteristics of the building, at the current fire safety engineering for actual development level and how the current "office building fire prevention design specifications" as the basic point of departure, establish the appropriate evaluation goals and functional requirements.
(2), style and performance prediction of structure for comparative analysis. According to the module 2 determine how existing office building fire prevention design specifications of performance requirements, the assessment provided by the module 3 building fire safety performance prediction results with fire safety standards, and performance-based assessment of the comparative analysis of the results.
(3) identification of the main weaknesses of fire safety. In comparison to the above two types of assessment on the basis of the results, use has been standardized by the cost-benefit analysis to determine improvement building fire safety performance of key links to specific fire safety measures provide the basis for decision making.
3.1.2 data integration
(1) fire scene selection. According to module 1 to determine evaluation goals and functional requirements, according to fire statistics data, select all fire scenario.
(2) to determine the forecast calculation parameters and performance-based criteria. According to module 3 determine the character prediction model and calculation method to fire the various input parameters, select and integrate related base data and performance criteria.
(3) to establish mandatory criterion. According to module 1 determine evaluation goals and functional requirements, the establishment of specifications for the design of the existing building fire performance requirements and specification standards.
3.1.3 traits forecast
(1) determine the fire behavior forecasting models and methods. According to module 1 to determine evaluation objectives and functional requirements as well as by the module 2 set fire scenario, established fire risk performance-based assessment of the systems involved, and select the appropriate model and calculation method to fire.
(2) analysis of various aspects of fire behavior forecast related impacts. For the fire safety of buildings may affect the performance of numerous factors should conduct a comprehensive analysis to fire until the evacuation is complete the whole process as the object of study. Prediction in character, it is necessary to study fire model, fire safety, evacuation operations and fire fighting procedures have performance characteristics, and to focus on the analysis of the interaction between subsystems.
(3) determine the predictive results. According to the module 2 fire statistics data, the results for characteristics and its prediction probability for statistical analysis, on this basis, identify the building fire safety performance prediction results.
3.2 performance of fire risk analysis method of the base content
3.2.1 fire scene selection
Building fire safety performance-based assessment objectives including human life, fire resistance of building structure and property loss in three areas. Once the destination to determine, on the need to identify potential fire hazards, select may cause the most undesired outcome of all fire scenario. In this connection, it should be under fire statistics, from the "object, resources, activities," a three-pronged approach, more systematically identify various types of fire scenario and the establishment of appropriate analysis of the various types of parameters required. Among them, the object is on fire ontology information structure, including the fire zone, unit level, fire, fire time distribution, part of the fire, the fire source, fire,
Weather conditions, fire, etc; resource refers to fire control of fire power, including fire engines, fire fighting equipment, fire service, etc.Situation; activities are those that fires during the various stages, including alarm, sortie, arrived at the scene, fighting, etc.
3.2.2 fire behavior forecast
In order to be able to can affect the performance of the building fire safety of the many factors make system, comprehensive and rational analysis of the need to fire up the whole process of evacuation is complete for the study of objects that are considered fire space internal fire and development stage, smoke and toxic gases during a fire spreading internal and external space stage, fire spread outside the fire space stage, fire detection and automatic fire extinguishing system startup phase, the fire brigade arrived at the fire-fighting and evacuation of fire behavior characteristics of the stage.
3.2.3 fire safety prediction of building structures
Performance prediction of building structures need to be on fire safety of building structures for analysis. In the analysis under fire scenario, determine the fire load, ventilation, separate the thermal properties of materials, and other basic data, predictive calculation fire temperature-time relationship, i.e. the temperature curve, you can use the standard temperature curve as under fire conditions. On this basis, the establishment of component heat conduction equations, and input materials thermophysical parameters and hydrolysis, calculation of the widget section of temperature, temperature field to determine the appropriate mechanical parameters, structure and widgets resistance calculation models, calculation component resistance. At the same time, determine the appropriate fire scene widget may withstand the gravity loads the payload, using mechanical analysis method of calculation component in effective load and temperature of load effect. Finally, through the analysis of Member resistance and load effects of related characteristics, the structure of the building and fire safety.
3.2.4 evacuation forecast
For building evacuation to a secure area of the time of the forecast results and fire scenario related to fire and smoke flow characteristics of the time. For evacuation time calculations, you must determine the number of key factors. First, unless it is located in the fire space officers discovered that prior to the commencement of the evacuation requires people to make the decision to evacuate action need time; Finally, evacuation operations begin. All of these links will take time, and these links are safe evacuation operations.
3.2.5 safety standards
In order to make the building fire risk assessment of the performance-based methods with strong adaptability, should develop a performance-based guidelines, branch standards, supplemented by way of security evaluation standard system. At the same time, in response to special circumstances can also develop additional guidelines.
3.2.6 comprehensive analysis of the results of the evaluation
On building fire hazard for performance-based assessment, the assessment of the objective is to identify existing buildings for fire safety meets the performance requirements of safety.
4 closing
At present the world architectural design fire protection standard is to develop performance-based specifications, performance-based specifications development direction — meet fire safety requirements, and to achieve the functional requirements of the building, built on the satisfaction of building fire risk basis, evaluation of the level of performance-based architectural design.