Hygienic efficiency

For evaluation the velocity distribution and capture velocity could be used. Since the worker is quite close to the contaminant-generating place, occupational hygiene efficiency is possible (Section 10.5). 

For exterior hoods, the measurement of capture velocity provides a quick check of the ideal design conditions. However, it must be remembered that capture velocity is not a direct measure of the ability of an exterior hood to provide personnel protection. Other efficiency measures are required in order to evaluate its performance in practice. The following two efficiency measurements could be useful capture efficiency and occupational hygiene efficiency. These measures complement each other. 

The occupational hygiene efficiency (tj ,) is defined as the ratio of the contaminant concentrations in the operator s breathing zone (Cj,) with the exhaust hood operating and not operating ... 

This gives a direct measure of the benefits obtained by the hood. In practice, the best way to determine the occupational hygiene efficiency is to measure the actual concentrations in the operator s breathing zone for those two cases. A tracer can also be used with the limitations described above. 

Note 2 Consider other important use-attributes convenience, domestic or Institutional use. heat retention, aesthetics, safety (e.g., insulation, breakage/leak resistance), hygiene (efficiency of washing process). 

A typical example of partial efficiency is the so-called "hygienic efficiency" used as a criterion to verify ambient air quality, which includes particles in the range of 0.5-5 pm considered harmful for the human respiratory system. 

Cleaning membranes to restore their efficiency is normal in UF. Food and dairy systems require daily cleaning in any event for hygiene more frequent cleaning is economically intolerable. A few industrial systems operate for six months between cleanings. Cleaning shortens membrane life, and it is often the major determinant of membrane-replacement frequency. 

SHEL (Safety Healthy Environmental and Loss Prevention Reviews) These reviews are performed during design. The purpose of the reviews is to have an outsider s evaluation of the process and layout from safety, industrial hygiene, environmental, and loss prevention points of view. It is often desirable to combine these reviews to improve the efficiency of the use of time for the reviewers. 

If the oxygen content of the contaminated air is deficient (refer to page 72), breathing apparatus is essential. The degree of protection required is determined by the level of contamination, the hygiene standard for the contaminant(s), the efficiency of any filter or adsorber available, and the efficiency with which the facepiece of the device seals to the user s face (this is reduced by beards, spectacles etc.). The level of comfort and user acceptability are further considerations. 

Defensive Measures Immunizations (which are questionable in efficiency), good personal hygiene, physical conditioning, wearing protective mask, and practicing good sanitation. Avoid unpasteurized milk products or raw meat. 

Determination of Desorption Efficiencies in the 3M 3500 Organic Vapor Monitor," presented at American Industrial Hygiene Conference, Houston, Texas, May 20, 1980. 

Phase Equilibrium. An equation has been derived (14) which relates the desorption efficiency to the volume of solvent and the amount of sorbent. The equation assumes the system is in equilibrium and can be approached from either direction. That is, the same desorption efficiency should be obtained when the compound is initially in the solvent or the solid phase. This has been shown to apply to most organic compounds in the concentration range of interest in Industrial Hygiene analyses. The equations below can be used to optimize the solid/liquid ratio when developing an analytical procedure ... 

All surface waters contain particles of different origin, sizes and materials, which must be removed efficiently before water distribution. There is a renewed interest in improved particle separation due to the hygienic problems with infectious cysts and oocysts of parasites (Gia-rdia, Cryptosporidium), which are particles in the size range of 3-12 (am. Depending on the raw water quality, particle separation may be accomplished typically by ... 

Efficient water usage and the application of alternative energy systems, as well as hygienic measures for diseases prevention, play a crucial role in the self-sufficiency approach. Sustainable changes of land use systems are unthinkable without investments in those sectors. 

The EUROPOEM expert group intended to extend the analysis on default values in the near future, taking account of the experimental evidence for protective efficiency in field studies. For the time being, a reduction factor of 10 is used for each body part and inhalation in case of appropriate hygienic behavior. The recent developments will be discussed in the final section, ( Conclusions and Recommendations ). 

Use adequate hygienic practices and respective efficiency assessment... 

---