Issue link: https://www.e-digitaleditions.com/i/1351840
18 Pharmaceutical Technology REGULATORY SOURCEBOOK MARCH 2021 P h a r mTe c h . c o m Operations Thermal testing Achieving worker efficiency under stressful heat conditions is difficult. Over the past 50 years, the impact of heat stress on productivity has been reported by the US Army and the National Aero- nautics and Space Administration (NASA), which published technical briefs on these issues as they relate to protective garments in the 1980s. In Figure 2 and Figure 3, heat load comparisons from thermal testing are shown graphically for re- usable vs. single-use garments. The FLIR images were taken using a FLUKE Ti125 Thermal Imager. The equipment was operating in the manual set- ting with one reference point (+) recorded. The manual mode of operation automatically scales the range of colors to the range observed in the image from 15.2 °C (blue/black) to 27.2 °C (white). These figures show the operator performing the same activity in the same cleanroom on the same day with one of two different garment types: • A reusable polyester cleanroom garment set, consisting of coverall, hood, boots, gloves, and goggles) • A single-use Tyvek garment set. Heat load could impact productivity A comparison of these images indicates that the operator skin temperature is approximately 5 °C higher when he or she wears the single-use gar- ment. One of the most common complaints re- garding cleanroom garments is that they are too warm to wear. In heat-stressed workers, a differ- ence of 1.5 °C could affect productivity. In this case, the difference is greater than three times the level that would be considered significant. The billowing effect also increases particle gener- ation (6). If the body temperature is elevated, there is a risk of additional microbial contamination from personnel. The data indicate that reusable garments are 5 °C cooler than the single-use gar- ments. Personnel who perspire and do not change garments when the garment is moist could risk a breach, allowing contamination to be transmitted through the garment or from garment billowing. All of these risks must be evaluated by the user when selecting a garment system. Life cycle of reusable garments Tests were performed in the body box using vari- ous types of reusable cleanroom garments that had been laundered for 10, 30, and 50 cycles (Figures 4a–c). The Y axis represents particles per cubic foot per minute with a size range of 0.5 microns and larger. The X axis represents hours in use. The maximum wearing for the operator was four hours (which included the testing after two hours). New Figure 3. In heat testing, single-use cleanroom garb (shown) generated higher heat load and more particulates than reusables.