Respirator performance testing

Subjects undergoing respirator protection tests are often required to perform simple exercises. Different testing and regulatory authorities require different exercises, but they typically include the following ... 

Comfort of the facepiece is also important. If the face-piece does not fit comfortably, the user may resist wearing respiratory protection, may become distracted and less attentive on the job, or may need to take additional breaks to find relief fiom the discomfort. The respirator fit test should always include a comfort assessment, especially when evaluating a facepiece the user has not worn in the past When performing the comfort assessment, consider the use of other personal protective equipment (PPE) such as safety glasses to ensure these can be worn properly and effectively with the selected facepiece. 

Bioassays. The biological activities of the synthetic peptides were determined using assay methods that were adapted to require only small amounts of peptide. Antifungal and antibacterial bioassays were performed in 96-well microtiter plates. Potential phytotoxicity was routinely evaluated using an oxygen electrode to measure inhibition of photosynthesis or respiration. All tests included magainin 1 or magainin 2 as a standard reference. Assay conditions were established to compare the relative activities of peptides, the absolute values cannot be extrapolated directly to activities in the field. 

Porphyrins and chlorophylls are the most widespread natural pigments. They are associated with the energy-converting processes of respiration and photosynthesis in living organisms, and the synthesis of specific porphyrin derivatives is often motivated by the desire to perform similar processes in the test tube. The structurally and biosynthetically related corrins (e.g. vitamin B,j) catalyze alkylations and rearrangements of carbon skeletons via organocobalt intermediates. The biosyntheses of these chromophores are also of topical interest. 

Experimental exposure studies have attempted to associate various neurological effects in humans with specific trichloroethylene exposure levels. Voluntary exposures of 1 hours resulted in complaints of drowsiness at 27 ppm and headache at 81 ppm (Nomiyama and Nomiyama 1977). These are very low exposure levels, but the results are questionable because of the use of only three test subjects per dose, lack of statistical analysis, sporadic occurrence of the effects, lack of clear dose-response relationships, and discrepancies between the text and summary table in the report. Therefore, this study is not presented in Table 2-1. No effects on visual perception, two-point discrimination, blood pressure, pulse rate, or respiration rate were observed at any vapor concentration in this study. Other neurobehavioral tests were not performed, and the subjects were not evaluated following exposure. 

For the Respiration Inhibition (RI) test performed routinely at the aforementioned laboratory the range of EC50 values obtained over a period of several months ranged from 4.5 to lO.Omg l-1. The AQC plot of these values is given in Figure 3.1.5. 

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