Experimental hazards

FIGURE 2.5. Flow Chart for Specific Experimental Hazard Evaluation for Reactive Substances... 

For full-scale processing, more accurate and more dedicated techniques using larger samples may be necessary, following the specific experimental hazard evaluation testing scheme outlined previously in Figure 2.4. 

CHETAH is a tool for the preliminary screening of the reactivity hazards of organic chemicals. The evaluation is based on pattern recognition techniques using experimental hazard data and estimated thermochemical data. 

Performance assessments are predictions of radioactivity releases, the rate of transfer of contaminants through various media, and the potential for hazard to the pubHc. These are based on a combination of experimental data obtained in the process called site characterization and detaded computations about radionuchdes and their effects. The progressive attack on the metal or ceramic waste container, the diffusion of water into the waste form, the leaching of the radioactive compounds, diffusion out, and washing away of radionuchdes are all considered. 

Pilot plants are often more hazardous than process plants, even though they are smaller ia size, for many reasons. These iaclude a tendency to relax standard safety review procedures based on the small scale, exceptionally qualified personnel iavolved, and the experimental nature of the research operations the lack of estabhshed operational practice and experience lack of information regarding new materials or processes and lack of effective automatic iatedocks due to the frequendy changing nature of pilot-plant operations, the desire for wide latitude in operating conditions, and the lack of hill-time maintenance personnel. 

Experimental screening involves conducting experimental tests to gauge the thermal hazard of materials and processes. The goal of these tests is to provide information by which the materials and processes may be characterized. Experimental screening can be performed for the following ... 

Caution/ Although the organic azide intermediates used in this procedure ham not shown any explosive hazard under the experimental conditions. 

The hazards and safety preeautions for seleeted eommon eompressed gases are diseussed below to illustrate the general approaeh. More details should be sought from suppliers. Some methods for their preparation in situ are noted full experimental details must be obtained from the literature. 

The assessment of the hazards of a partieular proeess requires investigating the effeets of these parameters through experimental work, interpretating the results in relation to the plant situation, and defining a suitable basis for safe operation. 

The evaluation of ehemieal reaetion hazards involves establishing exothermie aetivity and/or gas evolution that eould give rise to inei-dents. Flowever, sueh evaluation eannot be earried out in isolation or by some simple sequenee of testing. The teehniques employed and the results obtained need to simulate large-seale plant behavior. Adiabatie ealorimeters ean be used to measure the temperature time eurve of selfheating and the induetion time of thermal explosions. The pertinent experimental parameters, whieh allow the data to be determined under speeified eonditions, ean be used to simulate plant situations. 

Hazard characterization, or dose-response characterization, by using experimental animals to reveal target organs and toxic doses, and the shape of the dose-response curve... 

Hazard identification, step one, means identification of new chemicals or other factors that may cause harmful health effects. Previously, novel hazards were usually observed in case studies or after accidents or other excessive exposures, usually in occupational environments. Today, thorough toxicity studies are required on all pesticides, food additives, and drugs. New chemicals also have to be studied for their potential toxic effects. Thus, earlier hazards were in most cases identified after they had caused harmful effects in humans. Today, most chemical products have been evaluated for their toxicity with experimental animals. Therefore, hazard identification has become a preventive procedure based on safety studies conducted before a chemical compound or product reaches the market, and before individuals are exposed to it. ... 

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