The effect of contaminant source location on worker exposure in the near-wake region

Kulmala, Ilpo

doi:10.1016/0003-4878(96)00003-8

Cited by 21 publications

(17 citation statements)

References 13 publications

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“…In agreement with Malek, (5) Kim and Flynn (14) and Kulmala et al, (19) concentrations near the chest were higher than concentrations at the nose. Values of C chest in this study were almost always (34 of 36 samples) higher than the corresponding C nose values.…”

Section: Discussionsupporting

confidence: 88%

“…In nearly all Back orientation cases, as velocity increased, measured concentrations at all five sampler locations increased exponentially (Figures 3 and 4). That appears to disagree with the findings of Kim and Flynn (14) and Kulmala et al, (19) who found decreasing concentrations at increasing velocities. The findings cannot be compared directly with Kim and Flynn due to the much lower velocities in this study, but the highest two velocities overlap those in Kulmala et al The measured chest concentrations for both studies were taken at points in a horizontal plane in front of the mannequin rather than on the body of the mannequin, so the C chest results may not be directly comparable.…”

Section: Discussionmentioning

confidence: 62%

“…Kulmala et al (19) released a tracer gas at various horizontal and vertical distances from a lifesize mannequin in a wind tunnel. They found that tracer gas released above the shear layer of a downwash over the head produced little exposure at the mouth.…”

Section: Theoretical and Experimental Studiesmentioning

confidence: 99%

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Air Sampling at the Chest and Ear as Representative of the Breathing Zone

Guffey

Flanagan

Belle

2001

AIHAJ - American Industrial Hygiene Association

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Tracer gas concentrations were measured on a 60%-sized mannequin holding a pure sulfur hexafluoride source in its hands at waist height while it stood in a wind tunnel. Samplers were placed at the mannequin's mouth, in front of the ear, and at three chest locations at lapel level. Simultaneous 15-min time-weighted average samples were taken by drawing air into different sampling bags with sampling pumps. For the factorial study design, test conditions included cross-draft velocities of 10, 22, 47, and 80 ft/min; three mannequin orientations (facing to, side to, and back to cross-draft), and rotating speed through an 80 degrees arc (fast, slow, and no movement). Each study condition was tested twice. Concentrations at all sampling locations when the mannequin faced to the front and side were less than a tenth of the levels measured at the nose (Cnose) when the mannequin faced downstream. Higher velocities significantly increased concentration at the Back orientation and generally reduced it at the Side and Facing orientations. Concentrations at the nose were different from concentrations at other sites. For 34 of 36 samples the mean chest concentration (Cchest,) was higher than the Cnose (geometric mean three times higher). The ratio of ear (Cear) and Cnose varied with orientation. At the Back orientation, Cear, was lower than Cnose, whereas Cear was higher than Cnose at the Side and Facing to flow orientations. Velocity affected the ratios of concentrations. At the Back orientation, the chest sampler provided lower overestimates of Cnose, at higher velocities than at lower values. Mannequin movement, done only at the Back orientation, proved important only for the ear location. Results showed significant and substantial differences between concentrations at the nose and lapel. However, these findings should be interpreted with caution because a very dense tracer gas and an unheated, nonbreathing mannequin were used. In more realistic conditions, the findings probably would show far smaller differences in concentrations at different sampling sites.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 62%

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Air Sampling at the Chest and Ear as Representative of the Breathing Zone

Guffey

Flanagan

Belle

2001

AIHAJ - American Industrial Hygiene Association

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“…Kim and Flynn (1991) observed experimentally a strong downwash above chest level for an isothermal mannequin. Kulmala et al (1996) found a mean recirculation length of 1.5 diameter behind a mannequin, which depended little on the freestream velocity. Edge et al (2005) confirmed by RANS the existence of a recirculation region behind the torso, contributed by asymmetric vortex shedding.…”

Section: Wake Dynamics In Finite Bluff Body Flowsmentioning

confidence: 91%

Vortex dynamics and scalar transport in the wake of a bluff body driven through a steady recirculating flow

Poussou

Plesniak

2012

Exp Fluids

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The air ventilation system in wide-body aircraft cabins provides passengers with a healthy breathing environment. In recent years, the increase in global air traffic has amplified contamination risks by airborne flu-like diseases and terrorist threats involving the onboard release of noxious materials. In particular, passengers moving through a ventilated cabin may transport infectious pathogens in their wake. This paper presents an experimental investigation of the wake produced by a bluff body driven through a steady recirculating flow. Data were obtained in a water facility using particle image velocimetry and planar laser induced fluorescence. Ventilation attenuated the downward convection of counter-rotating vortices produced near the free-end corners of the body and decoupled the downwash mechanism from forward entrainment, creating stagnant contaminant regions.

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“…Studies investigated the effects of cross draft velocities on airflow patterns around a worker (Fletcher and Johnson, 1996;Kim and Flynn, 1992;Kulmala et al, 1996;Welling et al, 2001;Heist et al, 2003). They found that recirculation length downstream of the manikin (wake zone) depended on cross draft velocities and can be estimated using the manikin 1/2 dimensions.…”

Section: Manikins: Unheated and Non-breathingmentioning

confidence: 99%

Effect of breathing, posture, and air velocity on breathing zone gas concentrations for human subjects in a wind tunnel

El-Sotouhy¹

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Industrial hygienists generally place air-sampling probes on the mid to upper torso of workers when attempting to determine inhaled concentrations. There is no convincing evidence that concentrations measured on the chest are equal to inhaled concentrations. To determine how well surrogate locations matched concentrations at the mouth (C mouth), low concentrations of ethanol in nitrogen were released between the hands of standing and seated human subjects while they moved children's blocks back and forth over the source. I would like to extend my sincere appreciation and deep gratitude to Dr. Steve Guffey for making this accomplishment possible. I would like to thank him for having confidence and faith and willingness to spend all that time with me and giving me the opportunity to work on this project. Through his care and keen efforts, I have passed many difficulties and achieved immensely.

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The effect of contaminant source location on worker exposure in the near-wake region

Cited by 21 publications

References 13 publications

Air Sampling at the Chest and Ear as Representative of the Breathing Zone

Air Sampling at the Chest and Ear as Representative of the Breathing Zone

Vortex dynamics and scalar transport in the wake of a bluff body driven through a steady recirculating flow

Effect of breathing, posture, and air velocity on breathing zone gas concentrations for human subjects in a wind tunnel

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