Terms, Definitions and abbreviations

68 A safety function shouid prevent a specified hazardous event. For exampie, prevent the pressure in vessei ABC456 exceeding 100 bar. A safety function may be achieved by 

71 Safety instrumented functions are derived from the safety function, have an associated safety integrity ievei (SiL) and are carried out by a specific safety instrumented system (SiS). For exampie, ciose vaive XY123 within 5 s when pressure in vessei ABC456 reaches 100 bar . Note that components of a safety instrumented system may be used by more than one safety instrumented function. 

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Confer, R. and Confer, T. 1994. Occupational Health and Safety Terms, Definitions, and Abbreviations. Boca Raton, EL Lewis Publishers. 

Now, in the following clauses, various standards pertinent to different PHAs shall be discussed in brief. Mostly lEC standards wiU be covered. Each of these standards contains scope, normative references, terms, definitions, and abbreviations. These are not individually mentioned in the discussions while narrating the mtgor headings of a particular standard. For these, the reader is advised to refer to the corresponding standard. 

Confer, R. G. and T. R. Confer. 1999. Occupational Health and Safety Terms, Definitions, and Abbreviations, 2nd ed. Boca Raton, FL Lewis Publishers. This covers about 5,000 terms in the areas of industrial hygiene, safety, occupational medicine, and other related areas in acoustics, chemistry, physics, and biology. Terms on bacteriology, environmental health, epidemiology, illumination, mathematics, and microscopy are also included. 

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