Explosion, preliminary hazard analysis

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS (1995a p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous reaction scenarios-checklists, Dow fire and explosion indices, preliminary hazard analysis, what-if analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error analysis, and quantitative risk analysis. 

At Pantex, the preliminary hazards analysis takes the form of a questionnaire (PX-1245), which is used to collect information about facility inventories of highly hazardous chemicals, explosives, and nuclear material. This information serves as an objective basis for facility hazard classification. The information also allows ranking of facilities based on the quantity and form of nuclear material the eonsequences associated with an explosive event, as well as the type of explosives operation and the eonsequences of a release of highly hazardous materials. 

Pantex uses its Facility Hazard Classification as the basis for determining if a facility is nuclear (which requires the development of Authorization Basis Documents) or if a facility requires control under the plant s PSM program because it is classified as an Explosive Manufacturing Operation or has threshold inventories of Highly Hazardous Chemieals. The Preliminary Hazard Analysis serves as the safety basis for facilities that are not classified as nuelear or eoveied by PSM. 

Table 21.7.2 smnmarizes die results of applicadon of a preliminary liazard analysis (PHA) to the pyrolysis section of an ediylene plant. The major liazard to the persomiel and plant is die fire or explosion hazard of die gases used or produced in die process. 

The techniques used to complete PHAs inelude What-iF analyses. Explosive Safety Checklist Analyses, General Industry Checklist analyses and FMEA analyses. The information from Preliminary Hazards Analyses, previous Final Safety Analysis Report analyses. Fire Hazards Analyses, and other... 

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