Local protection

Emission Data or Calculation Model for Emission Source 

The tools for this task include design tools for calculation (models) and measured data of emissions in different processes, which are defined in Source Description. 

Suhprocesses are examined in order to provide proper working conditions locally or to reduce emissions to environment (see Fig. 3.9). 

Before considering ventilation, technical measures applied to process methods must be considered. 

The last method in protection of the worker is respiratory protective equipment. 

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Local ventilation systems (see Fig. 2.2) are used for local controlled zones. These systems are air technological methods for local protection. Primarily, local protection should be made using process methods such as encapsulation or process modification (see Design Methodology, Chapter 3). Another use for local ventilation systems is source capturing. 

In case use of local protection system effect on exposure of the process, load calculations shall he revised. products... 

If the local protection has an effect on the exposure of the source, recalculate the load. 

Make additional modifications, if returned from Local Protection... 

Step 6 Effect of Local Protection on the Emission of the Process... 

Consider whether the local protection influences the emission of the process. In that case, return to Calculation of Local Loads. 

After selection, return to Local Protection (design of general ventilation system). 

Loads from different sources to the general ventilation system are determined taking into account local protection. 

It should be remembered that, even with ordinary steels, high oxygen concentrations are locally protective, so that deoxygenation is not recommended if the metal to be protected is already cathodic. With stainless steel equipment, the Eh of the system must not be taken too low, otherwise the metal may become active (Section 16.6). 

Localized protection of external secretions. Complement fixation ... 

We have learned to contain corrosive media much more successfully in the last 20 to 30 years. This can be attributed to the many-fold increase in knowhow in metallurgy, in protective coatings and in the field of plastics. The need for overall protection of the structure or building has evolved into a more localized protection and is needless to say, more sophisticated. 

Inflammation is a local protective response to infection or injury whereby cells and proteins in the blood enter to remove the pathogens and repair the damaged tissue. Edema, redness, pain, and heat are the four cardinal symptoms of inflammation. Extent of reactions is determined by inflammatory mechanisms mediated by serum protein or cellular systems. Serum protein systems include complement, coagulation, fibrinolysis, and kinin cellular systems include PMN cells, mast cells, platelets, eosinophils, lymphocytes, macrophages, and reticuloendothelial system. Insufficient responses result in immunodeficiency leading to cancer and infections excessive responses are the cause of a number of chronic diseases like diabetes, cardiovascular disease, rheumatoid arthritis, multiple sclerosis, and Alzheimer s disease (Tracey, 2002). 

The fourth means of avoiding contamination from personnel sources is by localized protection of critical operations that necessitate manual intervention. This includes point of All and other operations like connecting and disconnecting feed lines, loading rubber plugs into hoppers, taking samples for quality control checks, etc. The issue to address in connection with localized protection is the extent to which it should be applied. There are two methods (a) total containment in an isolator or glove-box, and (b) protection by means of laminar Aow Altered air. 

Total containment of critical operations in isolators or glove boxes is localized protection at its most severe. These systems totally separate the operator from the process. They are quite commonly used in the nuclear industry and for handling highly toxic substances, carcinogens, and pathogens. 

Figure 5 illustrates a vertical laminar flow canopy such as might be used for localized protection of a filling machine or the off-loading station from a sterilizer. Fixed ot portable versions of this type of unit are available and have a wide application in aseptic manufacture. 

The final zone of protection is the localized protection given to point-of-fill and to manual processes conducted within the filling room. 

Areas used for filling products to be terminally sterilized should be maintained at a positive air pressure in relation to their surroundings, with a supply of filtered air. The filling operation, where products or cleaned empty containers are exposed, should be carried out in an atmosphere complying in terms of cleanliness with Grade 3 (Appendix 1) achieved either by general ventilation or by appropriate local protection (e.g. a contained work station). 

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