I-Risk: development of an integrated technical and management risk methodology for chemical installations

This paper presents an integrated quantitative risk assessment method for hazardous installations, taking into account management as well as technical design and producing risk level measures. The key components of the I-Risk methodology are the technical model, the management model and their interface. The technical model consists of developing a master logic diagram (MLD) delineating the major immediate causes of loss of containment (LOC) and associated quantitative models for assessing their frequency. The management model consists of the tasks, which must be carried out systematically in the primary business functions (such as operations, emergency operations, maintenance and modifications). A management audit quantifies the quality of these management tasks. The management–technical interface modifies certain parameters of the technical model on the basis of the quality of the safety management system of the specific installation. The methodology is exemplified through its application to the risk assessment of an ammonia storage facility. A detailed technical model simulating the response of the system to various initiating events is developed along with a detailed management model simulating the influence of the plant-specific management and organisational practices. The overall effect is quantified through the frequency of release of ammonia as a result of a loss of containment in a storage tank and in a pipeline.     

Barriers to interlock implementation

This commentary reviews current and past vehicle interlock programs for impaired driving offenders with a focus on the challenges that courts and motor vehicle departments face in attempting to implement mandatory programs as required by current federal legislation. There are few offenders in interlock programs compared to the large number of impaired drivers arrested each year. This suggests that, to increase participation, courts will have to threaten more severe sanctions for those offenders who reject interlock programs. A combination of electronic house arrest with interlock programs is suggested as a method of maximizing interlock use.     

Influence of seat foam and geometrical properties on BioRID P3 kinematic response to rear impacts

As the primary interface with the human body during rear impact, the automotive seat holds great promise for mitigation of Whiplash Associated Disorders (WAD). Recent research has chronicled the potential influence of both seat geometrical and constitutive properties on occupant dynamics and injury potential. Geometrical elements such as reduced head to head restraint, rearward offset, and increased head restraint height have shown strong correlation with reductions in occupant kinematics. The stiffness and energy absorption of both the seating foam and the seat infrastructure are also influential on occupant motion; however, the trends in injury mitigation are not as clear as for the geometrical properties. It is of interest to determine whether, for a given seat frame and infrastructure, the properties of the seating foam alone can be tailored to mitigate WAD potential. Rear impact testing was conducted using three model year 2000 automotive seats (Chevrolet Camaro, Chevrolet S-10 pickup, and Pontiac Grand Prix), using the BioRID P3 anthropometric rear impact dummy. Each seat was distinct in construction and geometry. Each seat back was tested with various foams (i.e., standard, viscoelastic, low or high density). Seat geometries and infrastructures were constant so that the influence of the seating foams on occupant dynamics could be isolated. Three tests were conducted on each foam combination for a given seat (total of 102 tests), with a nominal impact severity of Delta V = 11 km/h (nominal duration of 100 msec). The seats were compared across a host of occupant kinematic variables most likely to be associated with WAD causation. No significant differences (p < 0.05) were found between seat back foams for tests within any given seat. However, seat comparisons yielded several significant differences (p < 0.05). The Camaro seat was found to result in several significantly different occupant kinematic variables when compared to the other seats. No significant differences were found between the Grand Prix and S-10 seats. Seat geometrical characteristics obtained from the Head Restraint Measuring Device (HRMD) showed good correlation with several occupant variables. It appears that for these seats and foams the head-to-head restraint horizontal and vertical distances are overwhelmingly more influential on occupant kinematics and WAD potential than the local foam properties within a given seat.     

The impact of mandatory versus voluntary participation in the Alberta ignition interlock program

Research has demonstrated that participation in an interlock program significantly reduces the likelihood of subsequent driving while intoxicated (DWI) convictions at least so long as the interlock device is installed in the vehicle. Despite the growing number of jurisdictions that allow interlock programs and the demonstrated success of these programs, the proportion of DWI offenders who actually have the device installed is minimal. In an effort to increase the proportion of offenders using interlocks, some jurisdictions require offenders to install an interlock as a condition of license reinstatement whereas others merely offer offenders a reduction in the period of hard suspension if they voluntarily participate in an interlock program. The objective of the present study was to determine the extent to which voluntary interlock participants are more or less successful in terms of subsequent recidivism than those for whom interlock program participation has been mandated. The issue was addressed using data from the interlock program in Alberta, Canada, which provides for both mandatory and voluntary participation. The recidivism experience of voluntary and mandatory interlock participants was examined both during and after the period of interlock installation. Cox regression revealed that, after controlling for (or equating) the number of prior DWI offenses, the survival rates of DWI offenders who were ordered to participate in the interlock program did not differ from those of voluntary participants. These results suggest that further use of mandatory interlock programs should be just as successful as voluntary programs when offenders share characteristics with those studied in Alberta.