Removal Characteristics of Wipe Devices under Various Conditions

Abstract

Understanding the removal factor for specific conditions is essential to estimate removable surface contamination levels by wiping. The removal characteristics of dry foamed polystyrene pads and filter paper applied to polyvinyl chloride flooring are investigated using C-thymidine under various conditions (i.e., weight of contaminants, wax coating, temperature and humidity). Eight wipes were performed per flooring piece with a uniformly deposited contaminant to estimate the total removable surface contamination. The wipe devices were pressed against the surface by 2 kg-force with fingertips. The first wipe ratio (the ratio of the activity removed by the first wipe to the activity removed by eight wipes) from flooring on which was deposited 500 microg mL of C-thymidine solution varies between 24% and 71% for polystyrene pads and between 33% and 83% for filter papers, depending on the atmospheric humidity and temperature. For deposition concentrations of 1 microg mL, the mean first wipe ratio using polystyrene pads, which are almost constant vs. humidity and temperature, are 68% and 24% for waxed and unwaxed surfaces, respectively. Under the same conditions, the mean first wipe ratio for filter paper varied with both the surface and the environmental conditions. The total recovery (the ratio of the total activity removed by eight wipes to the total deposited activity) for deposition concentrations of 500 microg mL tended to increase with humidity for both wiping devices. The total recovery for deposition concentrations of 1 microg mL is generally low. The first wipe ratio in the lowest case with foamed polystyrene pads in this study was 19%. In that case, the total removable activity is speculated to increase from the sum of eight wipes, if additional wipes are performed. Therefore, the theoretical value of 0.1 recommended by ISO for the removal factor is appropriate when wiping polyvinyl chloride flooring using foamed polystyrene pads.

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“…resulting in a predicted removal factor of = -» F 1 0.46 0.11, 7 as also estimated in Shoji et al (2010). This value is close to the default value of 0.1 recommended in the ISO-7503 (1988ISO-7503 ( , 2016 standard.…”

“…Therefore, if the value of F i is known, one could consider it to be practical to use it as an estimate for f , i oth, or vice versa.hall (one compartment) with floor area The ISO-7503 (1988ISO-7503 ( , 2016 standard recommends a default value of 0.10 for the removal factor F i if experimental information on its actual value is missing. Experimental work by Shoji et al (2010) showed that this value is indeed appropriate for polyvinyl chloride flooring wiped with foamed polystyrene pads (appendix B). More information on wipe-sampling methods and on values of the removal factor (wiping or collection efficiency) can for instance be found in the following references: (Frame and Abelquist 1999), (Jung et al 2001), (Verkouteren et al 2008), (McArthur 1992, (US EPA 2011a), (Lichtenwalner 1992), (Sugiura et al 2007), (Ichiji and Ogino 2011), (Barbieri et al 2009).…”

A New Wiping Device for Detecting Removable Contamination

“…This means that wiping efficiencies might change in each case. Because various uncertainty factors exist, some studies aiming to reduce the inconsistencies in the wiping method have been conducted (Takiue et al 1989;Sugiura et al 2007;Shoji et al 2010). According to Saneyoshi et al (2006), a robot used for wiping could reduce the variability in wiping pressure.…”

Évaluation de la contamination bêta due au tritium par la réalisation de frottis et utilisation d’un appareil de scintillation liquide transportable

“…La norme prescrit une valeur de 10 %. Cette valeur basse, bien que généralement sous évaluée, est utilisée par les opérateurs, à titre conservatoire, pour le calcul de l'activité ou de la contamination surfacique labile (Shoji et al, 2010).…”