Methodology of fire risk analysis in electrical installations of a production facility

This article lists the principles of fire risk assessment and management of electrical installations, provides the main terms used in this subject area, and their meanings. The article also talks about factors affecting the magnitude of fire risk (risk-forming factors). Special attention is paid to the human factor. Formulas for probabilistic assessment of fire risks of electrical installations and an algorithm for assessing the fire hazard of electrical installations, as well as a scheme of the algorithm for calculating individual fire risk are given.

Fire Risk Analysis on Buildings Considering Fire Spread and Total Floor Area

Fire risk analysis models utilized for the fire risk assessment of domestic structures do not usually take into account flame spread and building size. Therefore, in this study, the effect of the building size on flame spread was investigated. Results showed that the frequency of occurrence of fires increased when the building has 11 or more floors. Additionally, the rate of occurrence of small-scale fires also increased when the total floor area was greater than or equal to 1,000 m2. From the risk analysis, the fire risk of health care, medical, and recreational facilities were calculated to be 25.7 × 10-3, 4.29 × 10-3, and 0.91 × 10-3 persons per year, respectively. As such, these were classified as high-risk facilities.

BN-RA: A Hybrid Model for Risk Analysis of Overload-Induced Early Cable Fires

Cable overload is one of the most critical contributors to early cable fires. This study proposes a hybrid Bayesian network (BN)-based fire risk analysis model, to investigate the evolution of overload-induced early cable fire risks. In particular, the fire risk transmission paths caused by cable overload are reported, considering the critical factors that likely lead to fires. A BN with a specific structure was considered using the fire risk transmission paths. Later, given the risk index system, a hybrid fire risk assessment model caused by cable overload was developed based on the entropy weight method. Subsequently, the corresponding risk levels were evaluated based on the evolution of the fire risk, using numerical simulations. Finally, a case study was conducted to validate the proposed methods, and the results indicated that the proposed methods can effectively evaluate the state of the cable and explain the causes of fire risk, which can be used for early fire warnings.

Battery Train Fire Risk on a Steel Warehouse Structure

Lithium ion battery fire hazard has been well-documented in a variety of applications. Recently, battery train technology has been introduced as a clean energy concept for railway. In the case of heavy locomotives such as trains, the massive collection of battery stacks required to meet energy demands may pose a significant hazard. The objective of this paper is to review the risk evaluation processes for train fires and investigate the propagation of lithium ion battery fire to a neighboring steel warehouse structure at a rail repair shop through a case study. The methodology of the analyses conducted include a Monte Carlo-based dynamic modeling of fire propagation potentials, an expert-based fire impact analysis, and a finite element (FE) nonlinear fire analysis on the structural frame. The case study is presented as a demonstration of a holistic fire risk analysis for the lithium ion battery fire and results indicate that significant battery fire mitigations strategies should be considered.

Technogenic Risk Optimization Method for Electrical Installations at a Production Facility

The level of technogenic safety at the production facilities of the Russian Federation is expressed by low values. In this regard, the fire situation is a major hazard: a significant share is represented by the fires that occur at the electrical installations (up to 30 %). Fire risk analysis includes the determination of the probabilities of the occurrence of a fire and its consequences in order to obtain the risk numerical value that determines the fire safety of the object, and its comparison with an acceptable (tolerable) level. The use of a semantic description of risk-forming factors characterizing a hazardous event, their linguistic assessment and the level of significance allows to obtain a range of numerical values for the fire risk of electrical installations. Mathematical modeling is accompanied by the construction of a two-dimensional vector characteristic of the quantitative and qualitative criteria for the integral risk of fire in the electrical installations, which represents a functional dependence on the indicators of the probability of a fire occurrence and the severity of its consequences (material damage). Description of the dynamic model a «human — electrical installation — environment», its life cycle, determines the characteristics of the system considering the fire conditions, and represents five stages: dynamic balance; violation of dynamic balance; destructive action (explosion, fire); restoration of normal functioning; the acquisition of a normal state. Based on this description, the fire risk numerical values at the electrical installation are obtained. When calculating fire risks, it is required to consider the nature of the «human — electrical installation — environment» system, since it is subject to the action of random processes and risk-forming factors that are caused by the presence of electrical installations and the external environment. Improvement of the electrical installations safety system requires using the new technical solutions, and the development of an algorithm for a technogenic safety management system. The main task of fire risk management is to optimize its level. The fire risk is used as a criterion determined by the totality of risk-forming factors of the human-machine system.

Uncertainty Modelling in Metamodels for Fire Risk Analysis

In risk-related research of fire safety engineering, metamodels are often applied to approximate the results of complex fire and evacuation simulations. This approximation may cause epistemic uncertainties, and the inherent uncertainties of evacuation simulations may lead to aleatory uncertainties. However, neither the epistemic ‘metamodel uncertainty’ nor the aleatory ‘inherent uncertainty’ have been included in the results of the metamodels for fire safety engineering. For this reason, this paper presents a metamodel that includes metamodel uncertainty and inherent uncertainty in the results of a risk analysis. This metamodel is based on moving least squares; the metamodel uncertainty is derived from the prediction interval. The inherent uncertainty is modelled with an original approach, directly using all replications of evacuation scenarios without the assumption of a specific probability distribution. This generic metamodel was applied on a case study risk analysis of a road tunnel and showed high accuracy. It was found that metamodel uncertainty and inherent uncertainty have clear effects on the results of the risk analysis, which makes their consideration important.

Methodology for Optimal Fire Evacuations in Underground Mines Based on Simulated Scenarios

The purpose of this chapter is to develop a methodology that will contribute in locating optimal evacuation routes in case of fire that are based on minimal carbon monoxide (CO) exposure during the evacuation procedures. The proposed methodology is tested using simulated fire scenarios from which CO concentration over time curve is extracted from all available evacuation routes and presented in a weighted form based on the accumulating effect of CO inhalation in the form of fractional effective dose (FED). The safety limits of the FED model on which the optimization process is based are determined using a model for the prediction of carboxyhemoglobin (COHb) levels in human blood. The COHb model is associated with predicted clinical symptoms that are the basis for determining the level of incapacitation at which the mineworkers are incapable of completing their evacuation. Also in the process of improving the fire risk analysis, the proposed methodology enables the development of evacuation plans that are based on the results of modeled fire scenarios combined together with the results of the anticipated hazards generated by CO inhalation. The results presented in this chapter indicate a more precise approach in the process of planning the evacuation system inside the underground mines.