Safety Benchmarks

Benchmarking can be undertaken in almost any area of business and organizational endeavor, including safety performance. The basic requirement is that key performance variables are identified, measured, analyzed, and compared to provide a basis for planned performance improvement. An optimum benchmark can be characterized by the following (Holloway, Lewis, and Mallory 1995,134)  

The benchmark should be measurable in terms of cost, time, value, or some other quantitative parameter. 

Benchmarks that use simple performance measures are often the best and the most easily accessible. 

The benchmarks should be available in external and competitive environments. 

If an actual external measure cannot be obtained, a well-founded estimate should be used as a substitute. 

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Since 1995, work on documenting and estimating the results of critical experiments has been carried out in the IPPE facility with the aim of including them in the International Handbook of Evaluated Criticality Safety Benchmark Experiments [3]. Currently, the following critical experiments have been included in the Handbook ... 

International Handbook of Evaluated Criticality Safety Benchmark Experiments, NEA/NSC/DOC (95) 03, September 1997 Edition. 

Years ago, safety pioneers saw the need for structured SMS that were risk based, management led, and audit driven. Based on sound management principles, they realized that safety must be measured if it was to be improved. This measurement had to gauge effort rather than experience in the form of injury rates alone. Modern systems do just that and form a sound basis for safety benchmarking internationally. 

A measurement that serves as a standard against others may be measured. Industry safety statistics (injuries, fatalities, fires, etc.) are commonly used as a safety benchmark measurement for comparison as a lagging safety key performance indicator. Better Safe than Sorry... 

The first task, the selection of appropriafe benchmark experiments, is greatly aided by the International Criticality Safety Benchmark Evaluation Project (ICSBEP). This project is managed through Idaho National Laboratory (INL) and involves nationally known criticality safety experts from various national laboratories in the United States. 

The work of the ICSBEP is documented as the International Handbook of Evaluated Criticality Safety Benchmark Experiments, which is distributed by INL as a set of annually updated CD or DVDs. The handbook currently contains 464 evaluations covering more than 4000 critical, near-critical, or subcritical configurations. Table 21.6 gives an overview of the experiments available from the database. 

Source ICSBEP International Critically Safety Benchmark Evaluation Project (http //icsbep.inel.gov/) (Accessed date 7/26/2014). 

ICSBEP International Griticality Safety Benchmark Evaluation Project. Available at http //icsbep. inel.gov (accessed July 2014). 

Safety benchmarks, if used, should be developed by employees for operatiorrs associated with their specific departments. In this instance, they may represent very site-specific requirements, which can be measured and morritored in association with performance indicators. 

Another way of interpreting absolute risk estimates is through the use of benchmarks or goals. Consider a company that operates 50 chemical process facilities. It is determined (through other, purely qualitative means) that Plant A has exhibited acceptable safety performance over the years. A QRA is performed on Plant A, and the absolute estimates are established as calibration points, or benchmarks, for the rest of the firm s facilities. Over the years, QRAs are performed on other facilities to aid in making decisions about safety maintenance and improvement. As these studies are completed, the results are carefully scrutinized against the benchmark facility. The frequency/consequence estimates are not the only results compared—the lists of major risk contributors, the statistical risk importance of safety systems, and other types of QRA results are also compared. As more and more facility results are accumulated, resources are allocated to any plant areas that are out of line with respect to the benchmark facility. 

A P2 audit differs from most other types of audits because it makes use of a dual benchmarking approach namely, it uses both technical (environmental performance) and financial performance as its basis for making corrective actions. The status quo most often serves as the benchmark, though other standards certainly can be devised. A P2 audit can also affect non-environmental issues. The types of corrective actions can affect other types of wastes, energy, occupational safety, product quality, and worker productivity. 

The setting of quantitative goals for indoor air quality also supports an organization s quality policy in the area of safety and health. Furthermore, the introduction of the target level concept for indoor quality will enhance the development of more advanced and efficient control technologies on a voluntary basis. One can assume that the diffusion of technology will make the present-day benchmark air quality common practice in, say, 10 to 20 years. 

The counterflow configuration has been extensively utilized to provide benchmark experimental data for the study of stretched flame phenomena and the modeling of turbulent flames through the concept of laminar flamelets. Global flame properties of a fuel/oxidizer mixture obtained using this configuration, such as laminar flame speed and extinction stretch rate, have also been widely used as target responses for the development, validation, and optimization of a detailed reaction mechanism. In particular, extinction stretch rate represents a kinetics-affected phenomenon and characterizes the interaction between a characteristic flame time and a characteristic flow time. Furthermore, the study of extinction phenomena is of fundamental and practical importance in the field of combustion, and is closely related to the areas of safety, fire suppression, and control of combustion processes. 

The elucidation of actinide chemistry in solution is important for understanding actinide separation and for predicting actinide transport in the environment, particularly with respect to the safety of nuclear waste disposal.72,73 The uranyl CO + ion, for example, has received considerable interest because of its importance for environmental issues and its role as a computational benchmark system for higher actinides. Direct structural information on the coordination of uranyl in aqueous solution has been obtained mainly by extended X-ray absorption fine structure (EXAFS) measurements,74-76 whereas X-ray scattering studies of uranium and actinide solutions are more rare.77 Various ab initio studies of uranyl and related molecules, with a polarizable continuum model to mimic the solvent environment and/or a number of explicit water molecules, have been performed.78-82 We have performed a structural investigation of the carbonate system of dioxouranyl (VI) and (V), [U02(C03)3]4- and [U02(C03)3]5- in water.83 This study showed that only minor geometrical rearrangements occur upon the one-electron reduction of [U02(C03)3]4- to [U02(C03)3]5-, which supports the reversibility of this reduction. 

Gaylor, D.W., R.L. Kodell, J.J. Chen, and D. Krewski. 1999. A unified approach to risk assessment for cancer and noncancer endpoints based on benchmark doses and uncertainty/safety factors. Regul. Toxicol. Pharmacol. 29 151-157. 

Similarly, in order to avoid any quantitative estimate, an MOE approach has been recommended by, e.g., JECFA (the Joint FAO/WHO Expert Committee on Food Additives) and EFSA (the European Food Safety Authority) in the assessment of compounds that are both genotoxic and carcinogenic by using a benchmark dose (BMD) approach to estimate the BMDLio (benchmark dose lower limit) representing the lower bound of a 95% confidence interval on the BMD corresponding to a 10% tumor incidence (see Section 6.4). 

This step involves planning the process of using external potentially useful information sources, including so-called solution databases (such as compiled by Lyngby, the Danish EPA and the Dutch TNO), safety perfor-mance/benchmarking data, literature on process safety and reliability, literature on cleaner production/pollution prevention, academic experts/... 

In addition to the need for scientific improvements to allow probabilistic risk assessments to be properly performed and interpreted, there also exists a need to educate stakeholders about what the US system for tolerance establishment and monitoring does and does not do. In simplest terms, the US system can be described as a food quality system but not necessarily a food safety system. This results from the fact that the pesticide tolerances are not safety standards but rather exist as enforcement tools that allow an assessment of how well pesticide application regulations are adhered to. Violative residues demonstrate the likelihood of pesticide misuse but should not be considered, in the vast majority of cases, to represent unsafe residues. Safety considerations govern whether or not the use of pesticides on specified commodities will be permitted tolerances, when granted, serve as indicators of good agricultural practices rather than as toxicological benchmarks. 

The analysis of the potential consequences of an accident is a useful way of understanding the relative inherent safety of process alternatives. These consequences might consider, for example, the distance to a benchmark level of damage resulting from a fire, explosion, or toxic material release. Accident consequence analysis is of particular value in understanding the benefits of minimization, moderation, and limitation of effects. This discussion includes several examples of the use of potential accident consequence analysis as a way of measuring inherent safety, such as the BLEVE and toxic gas plume model results shown in Figures 4, 5, and 6. 

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