Contamination control

Contamination Control. In a number of developing technologies, contamination by small particles is a serious problem. To the extent that... 

The minienvironment approach to contamination control has been increasing in use. A minienvironment is a localized environment created by an enclosure that isolates the product wafer from contamination and people (48). Another approach is using integrated processing, where consecutive processes are linked in a controlled environment (32). Both requite in situ sensors (qv) to measure internal chamber temperatures, background contamination, gas flow rates, pressure changes, and particularly wafer temperature (4). 

Before any remedial or preventive actions are implemented, an evaluation should be conducted as to appHcabiUty to the specific plant. The evaluation should continue while the actions are in progress. The main action should be to take measures to reduce the ingress of contaminants into the steam generator by using more rehable materials, such as in the condenser tubes, to reduce leakage. Contaminant control equipment, such as full-flow condensate deminerali2ers, should also be employed. 

Pesticides vary widely in their chemical and physical characteristics and it is their solubility, mobility and rate of degradation which govern their potential to contaminate Controlled Waters. This, however, is not easy to predict under differing environmental conditions. Many modern pesticides are known to break down quickly in sunlight or in soil, but are more likely to persist if they reach groundwater because of reduced microbial activity, absence of light, and lower temperatures in the sub-surface zone. 

Potable water treatment Granular activated carbons (GAC) installed in rapid gravity filters Removal of dissolved organic contaminants, control of taste and odor problems... 

Effective planning is again the key. We need to keep in mind that proper decontamination can be costly, but improper decontamination can be even more costly. One large but variable cost is the time it takes workers to decontaminate. The time that decontamination will take should be estimated and incorporated into the budget. In addition, contamination control and decontamination strategies and procedures should be outlined in the safety plan, communicated to workers, and implemented before any worker enters any area where there is a potential to become contaminated. 

As a general rule, contamination control procedures depend on... 

This chapter describes calculation models for building energy demand and air flow in and around industrial buildings. Special attention is paid to simulation of airborne contaminant control. 

Goodfellow, Howard D. Advanced Design of Ventilation Systems for Contaminant Control, Elsevier, Amsterdam, 1985. 

Fleikkinen, M, Study of Contaminant Sources in the Manufacturing hidustry, Proceedings of the 4th International Symposium on Ventilation for Contaminant Control, Stockholm, Sept S-9, 1994. 

R. Nicmela, P. Kalliokoski, J. Rantanen, A. Tossavainen, V. Riihimaki, and J Raisanen. In Ven-tilatinn 97 Global development in industrial ventilation. Proceedings of the Sth Internationa Symposium on Ventilation for Contaminant Control, ed. by H. Goodfellow and V.. Tahti, 1.53-140, 1997. 

G.J. farquharson. Building and facility design for clean and sterile pharmaceutical product manufacture. In J.H. Vincent, ed. Ventilation SS Proceedings of the Second International Symposium on Ventilation for Contaminant Control, pp. 231-236, Pergamon Pre.ss, Oxford, 1989,... 

Zhivov A. M., E.O, Shilkrot, P. V. Nielsen, and G. L. Riskowski. 1997, Displacement ventilation design. In Ventilation 97 Proceedings of the 5th International Symposium on Ventilation for Contaminant Control, vol. 1, pp. 427-438. Ottawa, Canada. 

Hoods are either enclosing or nonenclosing. Enclosing hoods provide better and more economical contaminant control because their exhaust rates and the effects of room air currents are minimal compared with nonenclosing hoods. For more detail regarding nonenclosing hoods, see Chapter 10. 

It the main reason for the stratification strategy is contaminant control in [he occupied zone, the same strategy should be applied in winter conditions, too. Thus, the selected hearing method has to fulfill two requirements to siip-pttrt the creation of the vertical stratification and not to create disturbing airflows into the hall. In this case one option would be the floor heating method see Fig. 8.16c. Additionally, one should consider the prevention of boundary layer flows along the outer walls using, for example, passive methods. -... 

The specific problems for BEOs are mostly related to the specific processes at which they are used. One problem that does not, directly, depend on the process is the use of the exhaust system. If an exhaust is not used, naturally it cannot remove contaminants. Although BEOs are less efficient than total or partial booths, their use is still justified. When the location of the BEO is not perfect, higher flow rates are usually required for contaminant control. However, it is better to use this type of hood than to have no local exhaust. 

Fume cupboards are frequently referred to as laboratory fume hoods and are a primary method of contaminant control within laboratories. 

Pckkinen, ]. Eloranta, M. Hyvarinen, J. Muttilainen, and E. Kahkonen. In Ventilation 94 Proceedings of the 4th International Symposium on Ventilation for Contaminant Control, Stockholm, Sept. 5-9 1994 (eds. A. Jansson and L. Olander). (Arbete och Hdlsa no. IS), Sweden National Institute for Working Life, 1994, pp. 276-280. 

L. M. Conroy and M. J. Ellenbecker. In Ventilation SS Proceedings of the 2nd International Symposium on Ventilation for Contaminant Control, 20-23 September 1988, London, England UK (ed. J. H. Vincent). Oxford, England Pergamon Press, 1989, 41-46. 

B. Fletcher and A. E. Johnson. In Ventilation 91 Proceedings of the 3rd International Sympo. Slum on Ventilation for Contaminant Control, September 16-20, 1991, Cincinnati, Ohio, USA (eds. R. T. Hughes, H. D. Goodtellow, and G. S. Rajhans). Cincinnati, OH American Conference of Governmental Industrial Hygienists, 1993, pp. 489-497. 

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