Date of Graduation
Statler College of Engineering and Mineral Resources
Industrial and Managements Systems Engineering
Steven E Guffey
Ethanol concentrations were measured on an anthropometrically correct, heated, breathing manikin holding a source in its hands at waist height while both sitting and standing in a wind tunnel. The manikin was oriented with its back to the cross draft velocity. Sampling probes were placed at the manikin's mouth, nose, forehead, neck, both collars, center chest and both lapels. Samples were taken from each probe concurrently for 15 minutes by drawing air at 0.15 L/min into separate Teflon(TM) bags using separate sampling lines. The work was divided into two studies each having factorial study designs and two replications of each treatment combination. Study I test conditions were 5 levels of cross-draft velocities (11, 27, 48, 82 and 104 ft/min), two levels of body heat (unheated/heated), and two levels of posture (sitting/standing). Study II conditions included the same postures and levels of velocities as well as two levels of breathing (breathing/no breathing) and two levels of hair style (wig/no wig) for a heated manikin.;The results of Study I showed that wind tunnel velocity (V), heating, the interaction of heating and velocity, and the interaction of posture and velocity each had a statistically significant (p<0.001) effect on log-transformed concentrations for all sampling locations. For the unheated manikin, concentrations for all sampling locations declined monotonically with wind tunnel velocity. However, for the heated conditions, concentrations varied with an inverted-V relationship with wind tunnel velocity. As expected, the effect of body heat was found to be more substantial at lower velocities (11 to 48 fpm) than at higher velocities (48 to 104 fpm). No unheated conditions were investigated in the second study because the first study established the importance of heating the manikin. The results of the heated conditions of Study II showed the same inverted-V relationship with velocity and similar effects of posture for all combinations of wig and breathing. Breathing was significant at all sampling locations. The interactions of breathing with other variables were significant at some locations but not at others.;In comparing ratios of concentrations of other locations to the concentrations measured at the mouth the ideal ratio is unity, but a ratio that varies little with velocity, posture, and other variables would allow use of correction factors. The results showed that the ratios deviated substantially from unity for most treatment combinations for every sampling location both for unheated and heated conditions and their deviations varied significantly with treatment conditions. These ratios were significantly related (p<0.01) to velocity and posture at every location. Heating and the interaction of heating with other variables were significant (p<0.05) for nearly all sampling locations. Likewise, breathing and wig and their interactions with other variables were significant for nearly all locations.;At the middle range of velocities, the collars, lapels, and lower sternum produced large (e.g., 100%) over-estimations for standing and large underestimations (e.g., 50%) for sitting. Surprisingly, the nose deviation ranged from 60% to 155%. The most reliable location was the neck followed by the forehead, but neither was consistently within 20% of the mouth.
Elnahas, Waleed Mahmoud, "Effects of heating, breathing, hair style, posture, and air velocity on breathing zone concentrations for an anthropometrically-correct manikin in a wind tunnel" (2005). Graduate Theses, Dissertations, and Problem Reports. 4146.