Assessment criteria

Afterwards, the vessels were pressurized according a proof test and a burst test with acoustic emission measurements. Acoustic emission data recorded during these tests are analysed in order to determine assessment criteria. The criteria are mainly based on ... 

The specific test was made into a specialized bunker of one partner of the CIAPES program. All the vessel was covered by AE sensors to locate witli accuracy AE sources. The corrosion defect was situated on the bottom of the vessel. The service pressure of the vessel was 8 bars, so the vessel was first submitted to a proof test at 12 bars. During this test, the pressure was increased with load holds in order to verify the assessment criteria. After the first hold at 4 bars, a cluster was located at the position of the defect. The number of events located in this cluster increased during all the test (figure 1). 

Clearly defined assessment criteria. Clearly defining the criteria against which existing PSM programs will be evaluated helps to minimize the margin for error and maximize objectivity. Ill-defined evaluation criteria require the person conducting the assessment to rely solely on individual skill and experience, which may or may not yield objective results. 

Bir, C.A. and Viano, D.C. Design and injury assessment criteria for hlunt ballistic impacts, J. Trauma, 57, 1218, 2004. 

Following a theoretical analysis of distributed small-plant manufacture, Benson and Ponton define assessment criteria for processes suitable for such processing [139]. Since micro reactors are one of the favorite and natural tools for distributed manufacture, this selection list also defines micro-reactor applications. In this context, the authors, probably in one of the first regular citations, emphasize that formulation processes, especially those with multiple ingredients, are particularly suited for distribution. The making of paint on-site is referred to as an already existing way to do so. It stands to reason to augment the scope from formulations to functional chemicals. 

A new 510(k) paradigm provides guidance for sponsors of 510(k)s to consider and use national and international standards and a mechanism for declaration of conformity assessment criteria for these standards. It is expected that many domestic and international standards will address, in part or full, certain aspects of... 

ESCIS 1993. Thermal Process Safety Data, Assessment Criteria, Measures. Safety Series, Booklet 8. Basel, Switzerland Expert Commission for Safety in the Swiss Chemical Industry. April. Order online at www.escis.ch/seiten/englrsh/ publication.htm. 

Laboratories meeting the assessment criteria shall be presumed to fulfil the criteria referred to in paragraph 1. Laboratories which do not meet the assessment criteria shall not be considered as laboratories referred to in Article 7 of the said Directive. 

Evaluation of the Army s Draft Assessment Criteria to Aid in the Selection of Alternative Technologies for Chemical Demilitarization (December 1995)... 

Oehlmann, J. (2002). Baseline study on intersex in Littorina Httorea with recommendations for biological TBT assessment criteria. Report, Johann Wolfgang Goethe University, Frankfurt am Main. SIME 02/6/1-E. 

Gygax, R. (1993) Thermal Process Safety, Data Assessment, Criteria, Measures,... 

The six key questions presented above ensure that the essential knowledge about the thermal safety of a process is addressed. In this sense, they represent a systematic way of analysing the thermal safety of a process and building the cooling failure scenario. Once the scenario is defined, the next step is the actual assessment of the thermal risks, which requires assessment criteria. The criteria used for the assessment of severity and probability are presented below. 

A proposal for assessment criteria on a four levels scale is presented in Table 3.1. This four levels scale for the severity is commonly used in the fine chemicals industry [4] and has its roots in the Zurich Hazard Analysis (ZHA) developed by the Zurich Insurance Company [5]. If the assessment is performed on a three levels scale, the upper levels critical and catastrophic may be merged into one level, high. ... 

Table 3.1 Assessment criteria for the severity of a runaway reaction.

For the assessment of probabilities, a six levels scale is often used [4], as proposed by the ZHA method [5]. Assessment criteria based on such a scale is presented in Table 3.2. 

The cooling failure scenario presented above uses the temperature scale for the assessment of severity and the time-scale for the probability assessment. Starting from the process temperature (TP), in the case of a failure, the temperature first increases to the maximum temperature of the synthesis reaction (MTSR). At this point, a check must be made to see if a further increase due to secondary reactions could occur. For this purpose, the concept of TMRad is very useful. Since TMRad is a function of temperature (see Section 2.5.5) it may also be represented on the temperature scale. For this, we can consider the variation of TMRad with temperature and look for the temperature at which TMRad reaches a certain value (Figure 3.4), for example, 24 hours or 8 hours, which are the levels in the assessment criteria presented in Sections 3.3.2 and 3.3.3. 

In the present chapter, some important aspects of reactor stability and the corresponding assessment criteria for normal operating conditions will be presented. In a second section, the assessment criteria for deviating conditions, such as cooling failure, are introduced. 

The thermal data of the reaction are summarized in Table 5.4. It should be noted that these criteria do not use any explicit kinetic data, but only the results of calorimetric experiments. For the decomposition reaction, by taking the activation energy into account, the safety limits of TD24 = 113 °C and Tm = 122 °C may be established, according to the assessment criteria presented in Section 3.3.3. The activation energy may be determined, for example, from DSC experiments, as described in Chapter 11. Without knowledge of the process conditions of temperature and feed rates, the assessment remains global, as shown in Table 5.4. More detailed assessment will be provided in the next chapters for different reactor types and process conditions. 

Table 10.1 Assessment criteria for the severity, using the energy (ATalt), the pressure for closed systems, and the extension for open systems.

The effectiveness of the implemented measures obviously depends on the technical environment in the plant unit where the process is to be implemented. Thus, the technical characteristics must be known for the assessment. The assessment of the controllability is based on the time-scale of the runaway reaction (TMRad), on the achievable pressure level, and on the gas or vapor velocities. A proposal for these assessment criteria is summarized in Table 10.2 ... 

For an open system, the vapor or gas velocities serve as assessment criteria. These velocities may be adapted and so are different of those encountered in emergency pressure relief, since here the aim is to control a runaway before it becomes critical. Criteria are provided for the velocities in a piping system and for the velocity across the liquid surface in a vessel, by assessing the swelling effect... 

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