Safety performance subjective methods

The assessment and analysis of the inherent safety performance in the hydrogen system requires sound and appropriate metrics. Several valuable proposals for inherent safety metrics (Cozzani et al. 2007, Tugnoli et al. 2007) as well as the main issues needed for such assessment are well summarized in the literature (Roller ef a/. 2001, Khan eta/. 2003). Recently, a novel consequence-based approach for inherent safety key performance indicators (KPI) assessment was proposed (Tugnoli et al. 2007). The approach bases the calculation of safety indicators on the evaluation of the expected outcomes of the hazard present in the system, by runs of specific physical consequence models. The KPI method was preferred in the current assessment framework, since, unlike other approaches, it allows easily fitting the peculiarities of the analysed systems and does not require subjective judgment. Furthermore, the KPI method was newly reviewed to describe some particular features of the hydrogen chain. In particular the assessment of transport units was added and new index aggregation rules were defined. 

What are some subjective methods for assessing safety performance ... 

Antioxidants should be used only when it can be shown that their incorporation cannot be avoided by appropriate manufacturing methods or packaging. Their intended performance in the product should be clearly stated—e.g., whether for the benefit of the active ingredient or an excipient. Their efficacy can depend on their nature, their concentration (subject to safety considerations), when they are incorporated in the manufacture of the finished product, the container, and the formulation (particularly their compatibility with other constituents). All of these issues should be addressed. Their activity should also be determined in the finished product under conditions simulating the use of the product. The extent of degradation should be determined with and without the antioxidant. 

Another subject of scientific debate is still the bioavailability and toxicity of bound residues (2). Data on this particular topic are sparse but tend to suggest the absence of hazardous effects of bound residues rather than the contrary. Answers that remain to be provided on this subject concern the relevance of these toxicological effects and, if the effects are viable, the best and most reliable method by which they can be measured and evaluated for a specific compound. As long as these questions are not answered satisfactorily, any attempt to address them can only be considered as a shot in the dark and a potential waste of finance and time. The industry is prepared to perform any additional safety evaluation as long as the answers are reasonable and can result in a greater guarantee of protection for the consumer. 

The process for converting the vegetation sample to a soluble form is selected for convenience, familiarity, safety, and optimal removal of interfering substances. A problem in dissolving salts of heavier Group IIA elements with mineral acids is that they may be insoluble sulfates. The most common method for bringing insoluble sulfates into solution is to subject the sample to hydroxide-carbonate fusion (fusion is discussed in Section 4.6.2 of your Radioanalytical Chemistry text). The fusion is performed in a metal crucible that is relatively insoluble under the fusion conditions. The temperature must be sufficiently high to melt the sulfates and convert them into carbonates. The carbonates are then dissolved to prepare the sample for analysis. 

Class II devices are those for which general controls alone are insufficient to assure safety and effectiveness, and existing methods are available to provide such assurances. In addition to complying with general controls, Class II devices are also subject to special controls. Special controls may include special labeling requirements, mandatory performance standards, and postmarketing surveillance. Examples of Class II devices include powered wheelchairs, infusion pumps, and surgical drapes. 

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