ASME HPS-2003 pdf download.HIGH PRESSURE SYSTEMS.
6400 SITING RISK CLASSIFICATION 6410 Objective The purpose of this paragraph is to provide a general procedure for assessing potential problem siting areas and planning appropriate actions. This Section provides means of estimating general qualitative values of risk, severity of hazardous consequences, and protection ef- fectiveness. This Section identifies four areas that shall be evaluated: (u) the facility (or system) relative to its surroundings (b) the permanent location of personnel (c) secondary equipment (d) protective systems This Section provides general information regarding the siting of systems protecting personnel and property against the effects of failure. A comprehensive probabi- listic methodology is recommended as a means to provide a greater assessment of effects of system charac- teristics, historical data, source-receptor (facility). This Section is used after the hazards have been identified (para. 6100), and estimates of the hazards magnitude is performed (para. 6200), and the criteria for hazards exposure to personnel is assessed (para. 6300). If neces- sary, protective systems (para. 6500) may be utilized to reduce the risk of injury and damage.
6422.1 Probability Estimate. This is the likeli- hood that an identified source event hazard will occur and result in a mishap or receptor event based on an assessment of such factors as: location, exposure in terms of cycles or hours of operation, and population density and distribution. The probability shall be esti- mated as follows: (a) Probability Estimate A. Likely to occur 2 (greater than or equal to) 10’ eventdyear or 1 evenuyear- source-receptor. (b) Probability Estimate B. Probably will occur in time 2 (greater than or equal to) to less than 10’ eventdyear or 1 event/l year to 1 event/100 years- source-receptor. (c) Probability Estimate C. May occur in time 2 (greater than or equal to) to less than loe2 events/ year or 1 evenu100 years to i event/10,000 years- source-receptor. (d) Probability Estimate D. Unlikely to occur < (less than) eventdyear or 1 event/10,000 years-source receptor. Two methods of probability estimate for source and/ or receptor are provided for the user of this Standard to assess each hazard posed by each facility, system (or component). Each of the two methods will have a rating category of event probability estimate A, B, C, D. The above event probability estimate A, B, C, and D are roughly modeled on the frequency versus fatality for total natural events as shown in Fig. 6422.1. Method #i allows the user of this Standard to collect existing operational data from specific facility, system, or component which has operated in an acceptable manner and use this data to develop frequency versus fatality criteria curve and thus develop probability esti- mates A, B, C, D.ASME HPS pdf download.