The main factors of breakthrough are known to sampling time, flow rate, concentration of the sample, temperature, humidity, and tee physical characteristics of the solid sorbent tube. However, no study has been reported the effect of temperature and sampling volume on the breakthrough of a charcoal tube during vinyl chloride monomer (VCM) sampling. The objective of this study is to suggest the optimal sampling condition during VCM sampling based on National Institute for Occupational Safety and Health(NIOSH) method.
To evaluate adequate sampling volume for VCM without breakthrough, volume of 1, 2, 3, 4, and 5 L each from VCM of 1, 5, 10, 15, and 20ppm at flow rate of 0.05 L/min were sampled in 22℃ and 40℃. At 22℃, in the case of 1, 5, 10, and 15ppm, VCM was absorbed completely in first section of charcoal tube regardless of sampling volume. But in 20ppm, detection rates are 99.56℃ in first section and 0.44℃ in second section. At 40℃ of 1ppm. VCM was adsorbed completely in first section. in 10, 15, and 20ppm, detection rates of second, third, and forth sections were decreased significantly by reduction of sampling volume, In determination of breakthrough based on NIOSH method, no breakthrough was occurred in 20ppm at 22℃. At 40℃, breakthrough was occurred in 10, 15, and 20ppm when sampling volume was 5L. Although no breakthrough was occurred when sampling volume was 3L.
Finally, in environment of temperature around 22℃, breakthrough may not occurred up to 20ppm during sampling for VCM. During sampling for VCM in environment of temperature around 40℃, no breakthrough occurred in 1-5ppm and 10-20ppm when sampling volume is 5L and 3L respectively. This result suggests that the sampling volume should be considered when VCM sampling under hot conditions (>22℃) by the NIOSH method No. 1007.
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