The International Organization for Standardization (ISO) standard 16900–1:2014 specifies the use of sodium chloride (NaCl) and corn oil aerosols, and sulfur hexafluoride gas for measuring total inward leakage (TIL). However, a comparison of TIL between different agents is lacking. The objective of this study was to measure and compare TIL for respirators using corn oil and NaCl aerosols. TIL was measured with 10 subjects donning two models of filtering facepiece respirators (FFRs) including FFP1, N95, P100, and elastomeric half-mask respirators (ERs) in NaCl and corn oil aerosol test chambers, using continuous sampling methods. After fit testing with a PortaCount (TSI, Inc., St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, five subjects were tested in the NaCl chamber first and then in the corn oil chamber, while other subjects tested in the reverse order. TIL was measured as a ratio of mass-based aerosol concentrations in-mask to the test chamber, while the subjects performed ISO 16900–1-defined exercises. The concentration of NaCl aerosol was measured using two flame photometers, and corn oil aerosol was measured with one light scattering photometer. The same instruments were used to measure filter penetration in both chambers using a Plexiglas setup. The size distribution of aerosols was determined using a scanning mobility particle sizer and charge was measured with an electrometer. Filter efficiency was measured using an 8130 Automated Filter Tester (TSI). Results showed the geometric mean TIL for corn oil aerosol for one model each of all respirator categories, except P100, were significantly (p < 0.05) greater than for NaCl aerosol. Filter penetration in the two test chambers showed a trend similar to TIL. The count median diameter was ~ 82 nm for NaCl and ~ 200 nm for corn oil aerosols. The net positive charge for NaCl aerosol was relatively larger. Both fit factor and filter efficiency influence TIL measurement. Overall, TIL determination with aerosols of different size distributions and charges using different methodologies may produce dissimilar results.

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Introduction -Laboratory experiments were conducted to ascertain whether Sharpie® brand black permanent marker ink will permeate through intravenous infusion bags. The practice of writing directly on infusion bags is a frequent yet controversial practice. There are no known written standards that exist which pertain to this practice. Methods -Five types of intravenous bags containing different solutions marked with black ink from a fine point felt tipped Sharpie® marker. Sample extraction occurred after infusion bags had been warmed to 40 C or remained ambient. Spectrophotometric scans and measurements were conducted at 300 to 600 NM on each solution contained in the experimental bags. Writing with Sharpie® pens on filter paper and surgical tape was also conducted. Results -A total of 17 experiments were conducted with intravenous bags of five different types of manufacture. There appeared to be no visible or ultraviolet spectrophotometric evidence of leaching of the ink from Sharpie® pens. Four different lot numbers of Sharpie® pens were used. Surgical tape that was written on using Sharpie® markers readily exhibited visible evidence of permeability. Discussion -The experiments conducted would appear to indicate that the infusion containers tested maintained an intact barrier to the application of Sharpie® brand permanent marker ink. Writing on surgical tape does not stop the permeability of Sharpie® pens. This study could serve as a suitable pilot study for others to conduct a much more comprehensive study using a greater number of intravenous containers, solutions and ink markers.