Hazardous operation

Some operations need to be carried out at low temperature, which requires refrigeration. The refrigeration fluid might, for example, be propylene and present a major hazard. Operation of the process at a... 

Reduce the frequency of hazardous operations such as sampling or maintenance. What is the optimum balance between rehability and maintenance ... 

Ways in whieh these prineiples are applied in praetiee are illustrated in the following seetion using eommon potentially hazardous operations or substanees ... 

Recognized systematic approaches include hazard operability study (HAZOP) event tree analysis fault tree analysis. 

Are work positions, machinery, pits or holes, and/or hazardous operations adequately guarded ... 

W. R. Acorn. Code Compliance for Advanced Technology Facilities A Comprehensive Guide for Semiconductor and Other Hazardous Operations. Park Ridge, NJ Noyes Publications, 199.3. 

In between, there will almost certainly be a numb of cases that are far less clearcut. For example, you may find situations in which PSM programs are well developed but fail to fully address a high-hazard process or a worst-case scenario in others, a facility engaged in relatively low-hazard operations may have a proportionately low level of PSM systems. 

Error free operation and maintenance can only occur within an effective management system. At the level of the task itself, this is provided by operating instructions. However, at a more global level, separate tasks have to be organized in a systematic manner, particularly if hazardous operations are involved, and where several individuals need to coordinate to achieve an overall objective. This section illustrates some accidents due to poor organization of work or failure to carry out checks. 

The analysis set out above demonstrates the importance of a comprehensive evaluation of the human aspects of a hazardous operation, from the point of view of identifying all contributory events and recovery possibilities. It also indicates the need for a complete evaluation of the operational conditions (procedures, training, manning levels, labeling, etc.) which could impact on these probabilities. 

Tliis particular case study does illustrate how event tree and fault tree analysis can be used in a hazard operability (HAZOP) study. 

Thresher, Applications of Suppressive Shielding in Hazardous Operation Protection , EM-TM-76-003 (June 1975)... 

A three-step nitration process of toluene is described. The advantages of the modified process are reduced waste, less hazardous operation, reduced oleum requirement, partial replacement of coned HN03 with dil HN03, and higher rate of toluene flow into the reactor (Ref 86) The continuous process of H.C. Prime (Ref 73) for preparing TNT was studied by thin-layer chromatography on silica gel with a starch binder and a fluorescent indicator. The nitration... 

Casey, Facility Design Reviews Program for Munitions Production Base Modernization and Expansion, Status Report , PATM 2178 (1975) 33) B.W. Jezek et al, Applications of Suppressive Shielding in Hazardous Operation Protection , Rept No EM-TR-76008, Edgewood Arsenal, APG (1975) 34) W.F. Nekevis et... 

New systems or processes may also need to be qualified from an operational safety perspective. This is particularly relevant in the case of chemical synthesis involving exothermic reactions. Critical safety aspects are usually identified using hazard operability or HAZOP assessments and studies. For example, a HAZOP analysis of an exothermic reaction vessel would involve consideration of the consequence of failure of the motors for mixers or circulation pumps for cooling water. Thus, the qualification of such a system would involve checks and assessment to ensure that the system/process can be operated safely and that pressure relief valves or other emergency measures are adequate and functional. 

Ways in which these principles are applied in practice are illustrated below by reference to common, potentially hazardous operations/substances ... 

Green II Landfill, Logan, OH (ACAP project) MSW and hazardous Operational 2000... 

Careful attention to such detail is necessary as a second line of defence against the effects of reactive hazards. The level of protection considered necessary may range from the essential and absolute minimum of effective eye protection, via the safety screen, fume cupboard or enclosed reactor, up to the ultimate of a remotely controlled and blast-resistant isolation cell (usually for high-pressure operations). In the absence of facilities appropriate to the assessed level of hazard, operations must be deferred until such facilities are available. 

United States Air Force. Development of Candidate Chemical Simulant List The Evaluation of Candidate Chemical Simulants Which May Be Used in Chemically Hazardous Operations, Technical Report AFAMRL-TR-82-87, Washington, DC Government Printing Office, 1982. 

Other factors that contributed to the severity of this disaster were also cited (1) proximity of high-occupancy structures (control rooms) to hazardous operation, (2) inadequate separation between buildings, and (3) crowded process equipment. 

Enclosures Enclose room or equipment and place under negative pressure. Enclose hazardous operations such as sample points. Seal rooms, sewers, ventilation, and the like. Use analyzers and instruments to observe inside equipment. Shield high-temperature surfaces. Pneumatically convey dusty material. 

Safety reviews A safety review (HAZOP study or equivalent study for hazardous operations) must be conducted by engineers, operators, and design specialists while the modification project is in the design phase. This allows (and encourages) safety changes to be made with minimum effort. Once the system is constructed, changes are difficult and costly to make. 

Blast resistant doors and conveyor gates to seal material handling penetrations during hazardous operations. 

SUMMARY. The safety record associated with the use of APE operated remotely or within operational shields is excellent. Operational shields that are properly designed, fabricated, and tested do provide operators with adequate protection, and ensures their safety during hazardous operations. 

Many hazardous operations require the use of pipelines to convey product material from one location to another. In time, these pipelines become lined with the hazardous product to the extent they could serve as a media for propagation of an incident from station to station. Therefore, periodically cleaning these lines of the hazardous residue is important to operational safety. Additionally, removing accumulations of residue in the pipelines will increase flow volume, operating efficiency, and will minimize the possibility of product contamination. 

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