Models for nearly every occasion: Part I - One box models.
The standard “well mixed room,” “one box” model cannot be used to predict occupational exposures whenever the scenario involves the use of local controls. New “constant emission” one box models are proposed that permit either local exhaust or local exhaust with filtered return, coupled with general...
| Publicado en: | Journal of Occupational & Environmental Hygiene Vol. 14; no. 1; pp. 49 - 58 |
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| Autores principales: | , |
| Formato: | equations & formulas research tables/charts Journal Article |
| Publicado: |
Taylor & Francis Ltd
Jan2017
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=120263475&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 120263475 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 15459624 V1L jtl: Journal of Occupational & Environmental Hygiene issn: 15459624 maglogo: Y pubinfo: dt: Jan2017 vid: 14 iid: 1 pid: 377 pub: Taylor & Francis Ltd place: Philadelphia, Pennsylvania artinfo: ui: 120263475 120263475 120263475 10.1080/15459624.2016.1213392 120263475 ppf: 49 ppct: 9 formats: fmt: – @attributes: type: T – @attributes: type: P tig: atl: Models for nearly every occasion: Part I - One box models. aug: au: Hewett, Paul Ganser, Gary H. affil: Exposure Assessment Solutions, Inc., Morgantown, West Virginia sug: subj: Occupational Exposure Analysis Ventilation Air Pollution, Indoor Prevention and Control Occupational Safety Human Structural Equation Modeling Methods Work Environment ab: The standard “well mixed room,” “one box” model cannot be used to predict occupational exposures whenever the scenario involves the use of local controls. New “constant emission” one box models are proposed that permit either local exhaust or local exhaust with filtered return, coupled with general room ventilation or the recirculation of a portion of the general room exhaust. New “two box” models are presented in Part II of this series. Both steady state and transient models were developed. The steady state equation for each model, including the standard one box steady state model, is augmented with an additional factor reflecting the fraction of time the substance was generated during each task. This addition allows the easy calculation of the average exposure for cyclic and irregular emission patterns, provided the starting and ending concentrations are zero or near zero, or the cumulative time across all tasks is long (e.g., several tasks to a full shift). The new models introduce additional variables, such as the efficiency of the local exhaust to immediately capture freshly generated contaminant and the filtration efficiency whenever filtered exhaust is returned to the workspace. Many of the model variables are knowable (e.g., room volume and ventilation rate). A structured procedure for calibrating a model to a work scenario is introduced that can be applied to both continuous and cyclic processes. The “calibration” procedure generates estimates of the generation rate and all of remaining unknown model variables. pubtype: Academic Journal doctype: equations & formulas research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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