HAZAN

If the consequences of failure are serious then we need a way of assessing the likelihood of the failure. The techniques used for this are known collectively as hazard analysis (Hazan), and their use requires expert advice. 

Kazan is carried out by a small team similar to that used in Hazop. The three steps in Kazan are  

The usual method of assessing the frequency of an incident is to constmct a fault tree. 

A fault tree is a diagram showing how primary causes produce events which can contribute to a particular hazard. There may be several ways in which a single primary cause can combine with other primary causes or events, so a single cause may be implicated in more than one hazard and may occur at different locations in the fault tree. 

The graphical structure of the fault tree makes it easy to see how primary causes and secondary events combine to produce hazards. Furthermore, by inserting the probabilities of occurrence of causes and events on the fault tree, one can compare the relative contributions of the different events to the probability of the hazardous outcome. 

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Kletz, T.A. (1999) HAZOP and HAZAN Identifying and Assessing Process Industry Hazards, 4th edn. Institutional Chemical Engineers, Rugby. 

Hazard analysis (HAZAN) is a quantitative way of assessing the likelihood of failure. Other names associated with this technique are risk analysis, quantitative risk assessment (QRA), and probability risk assessment (PRA). Keltz [44] expressed the view that HAZAN is a selective technique while HAZOP can be readily applied to new design and major modification. Some limitations of HAZOP are its inability to detect every weakness in design such as in plant layout, or miss hazards due to leaks on lines that pass through or close to a unit but cany material that is not used on that unit. In any case, hazards should... 

You liave been hired as a consultant to a company administrator who has a limited budget for die mitigation of hazards in a certain chemical plant. The plant employs two kinds of workers day employees tliat work one 8 hour sliLft daily, and sliift employees that rotate tlirougli tliree 8 hour shifts each day. A HAZOP-HAZAN report reveals two kinds of accidents are possible during plant operation. 

Kletz, T.AT (1983) HAZOP and HAZAN — Notes on the Identification and Assessment of Hazards, Instn of Chem. Eng., London. 

Kletz, T. A. (1999b) Hazop and Hazan Identifying Process Industry Hazards (Institution of Chemical... 

App, H., Hazan, R., Zilberstein, A., Ullrich, A., Schlessinger, J., and Rapp, U. (1991). Epidermanl growth factor (EGF) stimulates association and kinase activity of raf-1 with the EGF receptor. Mol. Cell. Biol. 11 913-919. 

Colin, J.-M. Hazan, C. Monticello, D. J., et al., Conversion of organosulfur compounds to oxyorganosulfur compounds for desulfurization of fossil fuels. Patent No. US6071738. 

Trevor A. Kletz, HAZOP and HAZAN, 3d ed. (Warwickshire, England Institution of Chemical Engineers, 1992). 

Basic engineering final flow sheets final PID data sheets for equipment, piping, process data on equipment, piping and instruments operating, start-up and shut-down procedures Dow F E Index, Mond Index, Hazop, Hazan, Fault tree, RISKAT... 

Kletz T.A., 1974. HAZOP and HAZAN - Notes on the Identification of Hazards, Institute of Chemical Engineers, Rugby. 

Canari, R. Hazan, B. Bloch, R. Eyal, A. M. Value Adding Through Solvent Extraction, (Proc ISEC 96) Shallcross, D. C., Paimin, R., and Prvcic, L. M., Univ. Melbourne Press, 1996, Vol. 2, 1517p. 

Funabashi Y, Floriguchi T, linum S, Tanida S, Harada S (1994) J Antibiot 47 1202-1218 Gellerman G, Hazan E, Kovaliov M, Albeck A, Shatzmiler S (2009) Tetrahedron 65 ... 

Hazard and risk analysis is a vast subject by itself and is extensively covered in the literature [22]. In order to plan to avoid accidental hazards, the hazard potential must be evaluated. Many new methods and techniques have been developed to assess and evaluate potential hazards, employing chemical technology and reliability engineering. These can be deduced from Fault Tree Analysis or Failure Mode Analysis [23], In these techniques, the plant and process hazard potentials are foreseen and rectified as far as possible. Some techniques such as Hazards and operability (HAZOP) studies and Hazard Analysis (HAZAN) have recently been developed to deal with the assessment of hazard potentials [24]. It must be borne in mind that HAZOP and HAZAN studies should be properly viewed not as ends in themselves but as valuable contributors to the overall task of risk management... 

HAZAN, on the other hand, is a process to assess the probability of occurrence of such accidents and to evaluate quantitatively the consequences of such happenings, together with value judgments, in order to decide the level of acceptable risk. HAZAN is also sometimes referred to as Probabilistic Risk Assessment (PRA) and its study uses the well-established techniques of Fault Tree Analysis and/or Event Tree Analysis ... 

A HAZOP study is cumbersome and time-consuming. However, it is believed that the outcome of a perfectly carried out HAZOP study is that no HAZAN (or PRA) study is needed. 

Kletz, "HAZOP and HAZAN - Identifying and Assessing Process Hazards", 3rd edition, IChemE, Rugby, 1992... 

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