Safety performance risk” defined

The government agency (or other procuring organization) for whom a system (or product) is being developed must determine the objectives and specifications for the project. The specifications should include standards of safety performance and define the levels of acceptable risk. The specific system safety tasks and requirements must also be defined. 

Arrester Testing and Standards Regulatory and approval agencies and insurers impose acceptance testing requirements, sometimes as part of certification standards. The user may also request testing to demonstrate specific performance needs, just as the manufacturer can help develop standards. These interrelationships have resulted in several new and updated performance test procedures. Listing of an arrester by a testing laboratoiy refers only to performance under a defined set of test conditions. The flame arrester user should develop specific application requirements based on the service involved and the safety and risk criteria adopted. 

There are four main uses of injury statistics (1) to identify high-risk jobs or work areas, (2) to evaluate company health and safety performance, (3) to evaluate the effectiveness of hazard-abatement approaches, and (4) to identify factors related to illness and injiuy causation. An illness and injuryreporting and analysis system requires that detailed information must be collected about the characteristics of illness and injuries and their frequency and severity. The Occupational Safety and Health Act (1970) established iUness and injury reporting and recording requirements that are mandatory for aU employers, with certain exclusions such as small establishments and government agencies. Regulations have been developed to define how employers are to adhere to these requirements (BLS 1978). 

Top-level criteria and requirements are defined primarily from two sources the regulator, whose concern is primarily public health and safety, and the user, whose concern is all encompassing (e.g. safety, performance, availability, and economics). Each of the four Goals has been quantified by a series of top-level criteria and requirements (Ref. 1, 2). The Top-Level Regulatory Criteria are a necessary and sufficient set of direct quantitative statements of acceptable health and safety consequences (doses) or risks to the public that are independent of reactor type and site. Demonstration of... 

A quantitative target for measuring the level of performance needed for safety function to achieve a tolerable risk for a process hazard. It is a measure of safety system performance, in terms of the probability of failure on demand. There are four discreet integrity levels, SIL 1-4. The higher the SIL level, the higher the associated safety level and the lower the probability that a system will fail to perform properly. Defining a target SIL level for a process should be based on the assessment of the likelihood that an incident will occur and the consequences of the incident. Table S.2 describes SIL for different modes of operation. 

Quantitative Risk Assessment. Previous sections in this chapter dealt with the identification, measurement, and mitigation of hazards in a chlor-alkali plant. Plant safety and Responsible Care programs define the objectives of continuous improvement in safety performance. The discussion of mitigation immediately above naturally leads on to the larger question of the most direct and cost-effective approach to this improvement. 

Safety functions are defined by lEC 61508-4 as operating in the high demand or continuous mode of operation if the demand rate is greater than one per year or greater than twice the proof test frequency. In this case, as discussed below, the measure of the safety performance of the safety function is the limit of hazard rate, h, that achieves tolerable risk. The relationship between the quantified safety performance and the SIL is given in lEC 61508-1 table 3, see Figure 2. 

The ERDEC Safety Office has since performed risk assessments on various detectors brought to government facilities for testing. Such procedures, when followed, permit the return of contaminated items to manufacturers. In the following, assessments of two detectors, the MiniRae and the M43A1 upgrade, are used as examples of how risks were assessed. Tables 3.16 and 3.17 define hazard severity and probability levels used as the criteria for assessing risk. 

Directive No. 89/391/EC, on the introduction of measures to encourage improvements in the safety and health of workers, defines the employer s commitment to perform risk analyses at a workplace (Section II, Article 6, Paragraph 2, 3) and notify workers of same (Section II, Article 10, Paragraph 1). The enactment defines principles of occupational health and safety with the main principles being the commitment of designers, project engineers, and users of machines and machinery to assess risks. 

In 1993, the Center for Chemical Process Safety (CCPS) published Guidelines for Safe Automation of Chemical Processes (referred to henceforth as Safe Automation). Safe Automation provides guidelines for the application of automation systems used to control and shut down chemical and petrochemical processes. The popularity of one of the hazard and risk analysis methods presented in Safe Automation led to the publication of the 2001 Concept Series book from CCPS, Layer of Protection Analysis A Simplified Risk Assessment Approach. This method builds upon traditional process hazards analysis techniques. It uses a semiquantitative approach to define the required performance for each identified protective system. 

Before scientifically sound research can be performed on a subject, clear definitions must be set. Although, this may seem a logical step, Osborn (Osborn et al., 1988) highlighted that this has been a stumbling block for research in safety science since its inception. Definitions of concepts like accidents, incidents, near misses, risk, and safety, are known in the field of safety science, but interpreted differently in various situations. Unclear and ambiguous definitions lead to misinterpretations and confusion and must be avoided. Therefore, some general concepts used in safety science and the definitions used in this thesis are discussed in this Section. In the remainder of this thesis specific concepts will be defined where appropriate and can also be found in a list of acronyms and definitions presented in the beginning of this thesis. 

It is widely understood within the industry that risk is defined as the combination of the probability of harm and the severity of that harm. Within the pharmaceutical industry whenever risk is considered the equipment or product being assessed must be viewed in the context of the protection of the patient. From our perspective, analytical instruments may impact on the validity of data that determines the safety and efficacy of drug products, or on the quality of the drug product. They may also impact on the identity or potency of the drug product and therefore it is important to ensure that risk management is performed throughout the complete life cycle of the instrument. 

There are of course many mathematically complex ways to perform a risk assessment, but first key questions about the biological data must be resolved. The most sensitive endpoint must be defined along with relevant toxicity and dose-response data. A standard risk assessment approach that is often used is the so-called divide by 10 rule . Dividing the dose by 10 applies a safety factor to ensure that even the most sensitive individuals are protected. Animal studies are typically used to establish a dose-response curve and the most sensitive endpoint. From the dose-response curve a NOAEL dose or no observed adverse effect level is derived. This is the dose at which there appears to be no adverse effects in the animal studies at a particular endpoint, which could be cancer, liver damage, or a neuro-behavioral effect. This dose is then divided by 10 if the animal data are in any way thought to be inadequate. For example, there may be a great deal of variability, or there were adverse effects at the lowest dose, or there were only tests of short-term exposure to the chemical. An additional factor of 10 is used when extrapolating from animals to humans. Last, a factor of 10 is used to account for variability in the human population or to account for sensitive individuals such as children or the elderly. The final number is the reference dose (RfD) or acceptable daily intake (ADI). This process is summarized below. 

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