Air change rate vs airflow pathway: bioaerosol containment and removal in patient rooms

Recent studies have shown that higher air change rates may have the unintended consequence of creating turbulent airflows that entrain high concentrations of infectious particles within the breathing zone, and possibly, breakdown pressure relationships necessary to contain the spread of infectious particles to other clinical spaces

Ventilation Rates and Airflow Pathways in Patient Rooms: A Case Study of Bioaerosol Containment and Removal

Most studies on the transmission of infectious airborne disease have focused on patient room air changes per hour (ACH) and how ACH provides pathogen dilution and removal. The logical but mostly unproven premise is that greater air change rates reduce the concentration of infectious particles and thus, the probability of airborne disease transmission. Recently, a growing body of research suggests pathways between pathogenic source (patient) and control (exhaust) may be the dominant environmental factor. While increases in airborne disease transmission have been associated with ventilation rates below 2 ACH, comparatively less data are available to quantify the benefits of higher air change rates in clinical spaces. As a result, a series of tests were conducted in an actual hospital to observe the containment and removal of respirable aerosols (0.5–10 μm) with respect to ventilation rate and directional airflow in a general patient room, and, an airborne infectious isolation room. Higher ventilation rates were not found to be proportionately effective in reducing aerosol concentrations. Specifically, increasing mechanical ventilation from 2.5 to 5.5 ACH reduced aerosol concentrations only 30% on average. However, particle concentrations were more than 40% higher in pathways between the source and exhaust as was the suspension and migration of larger particles (3–10 μm) throughout the patient room(s). Computational analyses were used to validate the experimental results, and, to further quantify the effect of ventilation rate on exhaust and deposition removal in patient rooms as well as other particle transport phenomena

The Influence of National Culture on Effectiveness of Safety Trainings During Postdisaster Reconstruction

Non-English speaking workers constitute a disproportionately high number of workers involved in postdisaster reconstruction. Additionally, the rate of fatality among these workers is higher than the industry average. Research shows this population is more prone to unsafe behaviors in the working environment, conceivably because many of these workers are sent into the field prior to any formalized training. Recent studies show that the native culture of construction workers can impact risk-taking behavior. While numerous researchers have attempted to develop training materials for Hispanic workers, the number of studies that consider the impact of native culture on safety behavior is minimal. To answer this emerging knowledge gap, this paper develops a framework that will help to discern the influence of native culture, as well as other socioeconomic characteristics, on the effectiveness of safety trainings for non-English speaking workers. The formulation of this framework will pave the way for an enhanced understanding of the impact native culture plays on unsafe behaviors within a diverse workforce. Foreseeably, this understanding will play a significant role in developing culturally sensitive training materials in the future

The Visibility of (In)security: The Aesthetics of Planning Urban Defences Against Terrorism

Urban defences against terrorism have traditionally been based on territorial interventions that sought to seal off and surveil certain public and private spaces considered targets. Lately, though, a much wider range of crowded and public spaces have been viewed as potential targets and thus have been identified as requiring additional security. This has immense implications for the experience of the ‘everyday’ urban landscape. Drawing on contemporary notions that incorporate the study of aesthetics and emotions within critical security and terrorism studies, this article discusses the visual impact of counter-terrorism security measures. It analyses the ‘transmission’ of symbolic messages, as well as the variety of ways in which security might be ‘received’ by various stakeholders. The analysis takes place against the backdrop of concern that obtrusive security measures have the capacity to radically alter public experiences of space and in some cases lead to (intended and unintended) exclusionary practices or a range of negative emotional responses. The article concludes by outlining a ‘spectrum of visible security’ ranging between traditional obtrusive fortified approaches and approaches that embed security features seamlessly or even ‘invisibly’ into the urban fabric

Project IMPACT: A Case Study of Developing a Manufactured Construction Workforce through Contextualized Training

With a looming shortage of skilled craft workers forecast to exceed 2 million by 2017, prefabrication may become a necessity for many U.S. contractors attempting to remain competitive with a smaller, lower-skilled workforce. Building components manufactured in a controlled, offsite environment have proven to reduce time, cost and site logistics while improving productivity, quality, safety and sustainability. However, entry-level workers, including more than 765,000 recession displaced manufacturing workers, often lack the basic skills necessary to retrain for jobs in manufactured construction. As a result, a $ 6.3M U.S. Department of Labor grant was awarded to an institutional consortium to develop online, contextualized training in manufactured construction and related manufacturing industries. Of more than 1,020 participants from 2012-16, learning outcomes from a focus group of 70 participants were statistically analyzed to compare the effectiveness of contextualized training among non-traditional student cohorts (e.g. older adults, veterans, women, minorities, etc.). Results indicate that graphic oriented, online training used in conjunction with traditional instruction, improved access and learning outcomes particularly among older adults, ethnic minorities and women

Ventilation Rates and Airflow Pathways in Patient Rooms: A Case Study of Bioaerosol Containment and Removal

Most studies on the transmission of infectious airborne disease have focused on patient room air changes per hour (ACH) and how ACH provides pathogen dilution and removal. The logical but mostly unproven premise is that greater air change rates reduce the concentration of infectious particles and thus, the probability of airborne disease transmission. Recently, a growing body of research suggests pathways between pathogenic source (patient) and control (exhaust) may be the dominant environmental factor. While increases in airborne disease transmission have been associated with ventilation rates below 2 ACH, comparatively less data are available to quantify the benefits of higher air change rates in clinical spaces. As a result, a series of tests were conducted in an actual hospital to observe the containment and removal of respirable aerosols (0.5–10 μm) with respect to ventilation rate and directional airflow in a general patient room, and, an airborne infectious isolation room. Higher ventilation rates were not found to be proportionately effective in reducing aerosol concentrations. Specifically, increasing mechanical ventilation from 2.5 to 5.5 ACH reduced aerosol concentrations only 30% on average. However, particle concentrations were more than 40% higher in pathways between the source and exhaust as was the suspension and migration of larger particles (3–10 μm) throughout the patient room(s). Computational analyses were used to validate the experimental results, and, to further quantify the effect of ventilation rate on exhaust and deposition removal in patient rooms as well as other particle transport phenomena