Hazard analysis determining considerations

Determination of criticahty (hazard analysis and consideration of assets vulnerahhity in a site). 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

Tliis cliapter is concerned willi special probability distributions and tecliniques used in calculations of reliability and risk. Tlieorems and basic concepts of probability presented in Cliapter 19 are applied to llie determination of llie reliability of complex systems in terms of tlie reliabilities of their components. Tlie relationship between reliability and failure rate is explored in detail. Special probability distributions for failure time are discussed. Tlie chapter concludes with a consideration of fault tree analysis and event tree analysis, two special teclmiques lliat figure prominently in hazard analysis and llie evaluation of risk. 

The terminology used varies considerably. Hazard identification and risk assessment are sometimes combined into a general category called hazard evaluation. Risk assessment is sometimes called hazard analysis. A risk assessment procedure that determines probabilities is frequently called probabilistic risk assessment (PRA), whereas a procedure that determines probability and consequences is called quantitative risk analysis (QRA). 

Evaluate the risks associated with the process and its safety systems taken as a whole, including consideration of people, property, business, and the environment, that could be affected by loss events and determine whether the risks have been adequately reduced (Hazard Analysis, Risk Analysis, Source Models, Atmospheric Dispersion, Estimation of Damage Effects). 

OSHA/USEPA requires employers, such as the chemical industry service sector, to perform an initial process hazard analysis (PHA) on processes covered by PSM/RMP standards. The PHA must be appropriate to the complexity of the process and must identify, evaluate, and control the hazards involved in the process. Employers are required to determine and document the priority order for conducting process hazard analyses based on a rationale that includes such considerations as extent of the process hazards, number of potentially affected employees, age of the process, and operating history of the process. 

A reactive chemicals/process hazard analysis (PHA) to be completed every three years (see Reference 11). Special consideration may be given to facilities that have lower levels of process risk and which have demonstrated superior safety performance to extend this frequency up to five years. Facilities that pose higher process risk or who have lower safety performance may be recommended to have reactive chemicals/PHA reviews more frequent than every three years. In certain countries, government regulation will determine the frequency and other requirements for Process Hazard Analysis reviews. Dow will follow the government requirements where they are more stringent. 

Many current flammability tests are based on perceived hazards and often involve flames applied to products or materials. Such tests use flames of different type, size, and duration, and test specimens of different size, shape, and orientation, although considerable rationalization has taken place recently. For historical reasons, they are often industry and or product based. The majority of these tests essentially determine whether a product will sustain combustion away from the ignition. source. When assessed in terms of fire hazard analysis, the effective differences between these flames may be minor compared to the actual fire scenario. 

Part 1910.119 presents the objectives of hazard analysis and some of the considerations that determine the choice of techniques. The material presented below in Section 16.4.2.4 is consistent with this discussion. The type of hazard analysis chosen should be appropriate to the complexity of the process studies, and there should be a system to ensure prompt action on the findings of the study. 

Sharing BPCS field devices with the SIS to achieve a redundant configuration may be acceptable, but requires additional analysis (e.g., ANSI/ISA-84.00.01-2004-1, Clause 11.2.10) to determine whether the shared devices are initiating causes for the hazard scenario under evaluation. Further, the fault tolerance requirements of ANSI/ISA-84.00.01-2004, Clause 11.4, should be examined. If the device is a potential initiating cause for the hazard scenario, it should not be used to meet the fault tolerance requirements. For example, SIL 3 requires a minimum fault tolerance of 1 for the final elements when other criteria of ANSI/ISA-84.00.01-2004, Clause 11.4.4.4, are met, yielding the requirement for a 1oo2 architecture. The control valve cannot be used to meet the fault tolerance requirement, if it is the initiating cause for the hazard scenario under consideration. 

The purpose of this step is to determine the safety requirements specification for the system under consideration which should be examined in the light of the hazard analysis carried out in Step 2. (It should be noted that a superficial analysis of the safety requirements specification should be done in this Step but only so far as to allow step 4 to be carried out the full assessment being carried out in step 5.)... 

Only when the above analysis has been completed, should consideration be given to the types of PPE to be used. A job hazards analysis (JHA), as described in Chapter 2, wiU help determine what type of PPE is needed and when and where it should be worn. 

Do a job-hazard analysis. A job-hazard analysis (JHA) is a method of identif5dng, assessing, and controlling hazards associated with specific jobs. A JHA breaks a job down into tasks. You evaluate each task to determine if there is a safer way to do it. A job-hazard analysis works well for jobs with diffiicult-to-control hazards and jobs with histories of accidents or near misses. JHAs for complex jobs can take a considerable amount of time and expertise to develop. You may want to have a safety... 

Most of the techniques for determining risk or identifying hazards that are discussed herein require analysis by committee. The committee must be formed from individuals having specific and relevent experience to the chemical process under consideration. Furthermore, the management of this committee is paramount to the success of the project. Members must focus on the problem at hand and continue to make satisfactory progress. 

Widening interest in the quaHty of the environment has led to increased demand for information on a wide range of trace-metal contents of foodstuffs. Trace metals in foodstuffs are normally determined by spectroscopic techniques after complete destruction of the organic matrix. Destruction is achieved either by wet oxidation or by dry ashing additional treatment is normally required in order to obtain the metals of interest in a form suitable for analysis. Both methods of destruction are time consuming and tedious this is particularly true of the wet-oxidation procedure, which has the additional disadvantage of being potentially hazardous the methods require considerable analytical skill and experience. Both methods are prone to produce erroneous results either by the loss of an element of interest or by adventitious contamination from the component parts... 

Considerable attention has been directed toward development of IR spectral analytical techniques for HMX and related compds. Ref 56 discusses the analysis of alpha, gamma and delta HMX in beta HMX, and presents a detailed literature survey of the properties of HMX polymorphs, and hazard.aspects connected with the transitions between the stable beta form and its polymorphs, Spectrophotometric analysis of HMX in PBX 9404 (a plastic bonded expl) is documented in Ref 53. IR techniques have also been useful in. the determination of the effects of Idw level gamma radiation on the thermal sensitivity of HMX, RDX and HMX—RDX mixts (Ref 61)... 

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