Safety distance

A great deal of experimental work has also been done to identify and quantify the ha2ards of explosive operations (30—40). The vulnerabiUty of stmctures and people to shock waves and fragment impact has been well estabUshed. This effort has also led to the design of protective stmctures superior to the conventional barricades which permit considerable reduction ia allowable safety distances. In addition, a variety of techniques have been developed to mitigate catastrophic detonations of explosives exposed to fire. 

The scraper or knife discharge consists of a blade that removes the cake from the dmm by direct contact with the filter cake. It is normally used for granular materials with cake thickness greater than about 6 mm. In order not to damage the filter cloth, a safety distance of 1 to 3 mm between the blade and the cloth must be observed. If the residual layer is made not of filter aid but of the product, there is danger of its blocking by fine particles and by successive consoHdation by the scraper blade. 

Janet, D. E. 1968. Derivation of the British Explosives Safety Distances. Ann. NY Acad. Sci. 152. 

For the purposes of safety distances in connection with the issue of licences for factories and magazines, explosives have been categorized as X — fire or slight explosion risks or both, with only local effect Y — mass fire risks or moderate explosion risk, but not mass explosion risk Z — mass explosion risk with serious missile effect ZZ — mass explosion risk with minor missile effect. 

Plant layout is a crucial factor in the safety of a process plant because of e.g. segregation of different risks, containment of accidents and limitation of exposure. Safe plant layout is designed on the basis of design standards and local regulations. These are often expressed as minimum clearances between equipment. Safety distances between plant items can in principle be calculated by estimating the size of possible leaks, the probability of ignition and explosion... 

The importance of this case is that OS-CFAR can be analytically analysed without any approximations. Furthermore the resulting scaling factor Tos is completely independent of p. Figure 14 shows the typical behaviour of OS-CFAR in clutter edge and multiple target situations. The threshold follows the clutter contour with a certain safety distance. In two target situations the threshold is more or less unchanged compared with a pure noise situation. 

The activities at Picatinny Arsenal have been separated to comply with safety distances and all known means are employed to safeguard workers. When accidents have occurred, it has been due to these precautions that injuries to employees and loss of material or damage to buildings have been kept to a minimum at Picatinny... 

The individual operations are carried out in danger buildings , separated by safety distances. These distances are reduced if the buildings are mounded. For unmounded buildings the average safety distance is 50 m. A blow-out construction... 

Absperrzone = blast area 36 Abstand Sicherheitsabstand = safety distance 138... 

British Explosives Safety Distances , See Ref 8, pp 18-35 13) H.L. Callaghan, Practical... 

Any process heat plant design implies piping through the containment to connect the reactor vessel with the chemical plant. The fracture of a pipe could result in the accumulation of a flammable gas mixture in the containment. Precautions must be taken to minimize the risk of a fire or gas explosion such as avoidance of explosive gas ingress, proper detection devices, inerting, sufficient safety distances, appropriate layout of secondary coolant boundary, explosion-proofed wall, plant isolation valve. For the PNP-500, the use of two concentric pipes for the process gas carrying lines were recommended. Alternatives are concrete channels around the gas lines or inerting of the containment [10]. 

An argument for a safety distance reduction could be the deployment of an underground, non-pressurized LNG storage tank and ventilation system [34]. 

For a nuclear coal gasification plant, the above safety distance relation is probably not practicable. Therefore it has to be guaranteed by respective studies, that the load upon the nuclear reactor building in case of an outdoors explosion is covered by the design limits. 

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