Self-Organizing Map and clustering algorithms for the analysis of occupational accident databases

Data mining techniques are a powerful method for extracting information from large databases. Among these techniques, clustering and projection of data from high-dimensional spaces hold a main role, since they allow to discover hidden structures in the data set. Following this approach, this paper presents a data analysis method designed to help the management and investigation of occupational accident databases. The purpose is to discover the most common sequences of events leading to accidents for devising preventive actions. To this aim, we developed a two-level approach based on the joint use of the Kohonen’s Self-Organizing Map and the k-means clustering algorithm. This approach allows not only to group the accidents in different classes but also to visualize them in a way understandable for the analyst. The method has been applied with satisfactory results to a large database of occupational accidents occurred in the Italian wood processing industry. A comparison with the Hierarchical Clustering method confirmed the effectiveness of the proposed approach.     

Missing safety measures led to the jet fire and seven deaths at a steel plant in Turin. Dynamics and lessons learned

The Authors of this paper are the technical experts that were entrusted by the Public Prosecutor to conduct the technical inquiry into the accident that occurred in the ThyssenKrupp plant in Torino on December 6, 2007. The paper contains the results of the inquiry under the above mentioned point of view. The dynamics of the accident, the main causes and the consequences have been defined.This was an unusual accident from which important lessons can be learned. On December 6, a modest fire developed in the entry section of a pickling and annealing line in the TK plant in Turin. The eight workers on duty seized the firefighting equipment and started to try to extinguish the fire. The workers had portable fire extinguishers and a fire hydrant, so they had to get close to the fire to fight it. Suddenly, a violent jet fire, caused by the rupture of a hydraulic circuit, occurred. The flame instantaneously struck the eight workers while they were still fighting the fire. Seven workers suffered very serious burns, one died instantaneously while the other six had over the following month. One of the workers, who was partly protected by an operating machine, suffered only minor burns and survived. The paper contains some important lessons that have been learned from the present case, which demonstrate that the fire risk at pickling and annealing lines has generally been underestimated by the steel industry. The fire risk due to hydraulic actuators is also evident and new fire fighting strategies are suggested.     

Large N.G. explosion and fire involving several buried utility networks

This paper describes an accident (explosion and natural gas fire) that occurred in Turin (Italy), in which power distribution cables, tramway network feeding cables and a gas pipe were involved.The described accident is particularly interesting because it occurred in the town centre and lasted several hours, producing a very high risk for the population. Fortunately, nobody was injured, but 120 people were evacuated for 24 h. The sequence of events is described, the involved facilities are examined and the physical processes which led to the different top events are discussed. Actually, starting from a modest event (600 V electric cable loss of insulation), which most likely lasted for months, the aforementioned accident was reached in a crescendo of domino effects. This sequence has been represented by an ISD in which the failure of the different protection systems is highlighted. These protection systems were mostly based upon the strict respect of procedures both in the installation and in the following maintenance of the different utilities. These aspects have been also briefly devised in the light of Italian and foreign regulations concerning the problem of the coexistence of buried utilities.     

Numerical modeling as a tool for evaluating the renewability of geothermal resources: the case study of the Euganean Geothermal System (NE Italy)

Environmental Geochemistry and Health - Renewable natural resources are strategic for reducing greenhouse gas emissions and the human footprint. The renewability of these resources is a crucial...     

A reliability data bank for the natural gas distribution industry

This study is an extended and updated version of those already reported. It illustrates the results obtained from ordinary maintenance operations on six large sets of urban mains, with a view to optimizing the establishment of a reliability data bank. The study illustrates the extreme individuality of gas distribution plants and the need for a sector data bank.