Search

Since the 1990s, improvements in ventilation techniques and isolation procedures have been widely credited with the decline in nosocomial transmission of tuberculosis and other airborne diseases. Little effort, however, has been made to study the risk of isolation patients acquiring secondary infections from contaminated air migrating into negatively pressurized isolation rooms from adjacent spaces. As a result, an actual hospital was used to observe the transport of aerosol from a nursing station and general patient room to a nearby airborne infectious isolation room (AIIR). Aerosols ≤3.0μm (viruses and most airborne bacteria) were found to be capable of migrating 14.5m from a general patient room to an AIIR anteroom entrance in 3.0μm to the entrance of the general patient room (4.5m).

Approximately half of the nosocomial aspergillosis outbreaks in hospitals have been associated with renovation activities. When disturbed, spores encapsulated in building materials can be aerosoliz...

Placing an Airborne Infectious Isolation Room (AIIR) into a negative pressure has proven to protect the hospital from fatal pathogens such as tuberculosis and other airborne diseases. However, this pressurization strategy could increase the risk of isolation patients acquiring secondary infections from contaminated air drawn in from adjacent spaces. As a result, an actual hospital was used to observe the transport of aerosol from a general patient room and nurse station to a nearby airborne infectious isolation room. Two experimental studies were designed to analyze the performance of a negative anteroom. Aerosols ≤3.0 μm (viruses and most airborne bacteria) were found to be capable of migrating out of a general patient room to the vicinity of the nurse station. Concentrations of aerosols within the anteroom and isolation room increased from ambient when injected at the nurse station, indicating the capability of aerosols to migrate into the isolation room upon negative pressurization. Subsequently, a series of CFD models, validated by the experiments, were developed to simulate a positively pressurized anteroom. An anteroom with a positive pressure was shown to effectively terminate cross-contamination between the corridor and the isolation room in both directions.

Certain pathogens are transmitted through air by respiratory droplets that desiccate shortly after emission and form droplet nuclei (Nicas et al. 2005). Droplet nuclei are sufficiently small (

Benchmarking energy performance of existing residential buildings’ envelopes remains a challenge due to the complex physical and non-physical interacting factors of buildings. Regression analysis with sufficient data samples can be attractive for benchmarking application due to its capability in neutralizing the effects of noise variables. However, multicollinearity effects among explanatory variables often lead to unreliable regression models, especially in cases of high-dimensional variables. Principal Component Regression can transform co-linear variables via principal component analysis to orthogonal components and simultaneously has the neutralization function of linear regression analysis of high dimensional dataset. A new benchmarking method is developed using multivariate linear regression analysis with principal component analysis to address the multicollinearity risk with high dimensional dataset. The method was applied to datasets of a real project. The results indicate that Principal Component Regression is able to address multicollinearity risk, through using fewer orthogonal principal components that are linear combinations of original variables. The benchmarking outcome using this method is validated through infrared thermography validation. The benchmarking result is superior to that of the traditional statistical rating method using average energy consumption of buildings.

With high unemployment and structural changes to industry, workforce development in the United States is a growing concern. Many semiskilled workers lack knowledge, skills, and abilities to be competitive for reemployment to green jobs. Nebraska’s syNErgy research grant was introduced to address the training needs of unemployed and underemployed construction and related industry workers in the state. This study presents methods for determining the needs and developing the curricula for workforce development. Methodology is examined for its effectiveness in addressing an ongoing societal need. A series of curricula was developed for the purpose of retraining the State’s workforce in new and emerging green construction jobs. Research limitations and conclusions are discussed.

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 vast majority of some 22-million manufactured housing residents in the United States are ethnic, elderly, low-income populations. As the fourth most populous and second fastest growing US state, Florida is home to one of the nation’s largest concentrations of manufactured homes in one of its most geographically vulnerable regions. After-action reports from Hurricanes Charley, Jeanne, Frances, and Ivan indicate that all manufactured housing units constructed after the 1994 Federal Manufactured Housing Construction and Safety Standard survived intact, whereas units constructed before 1994 suffered damage ranging from severe to catastrophic. This paper provides manufactured housing damage-assessment data from 60 of 67 Florida counties affected by the 2004 hurricane season according to various federal and state hazard mitigation strategies implemented from 1976 to 1999.

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.

Hospitals are among the most energy intensive buildings in industrialized countries, using more than two-thirds of total energy consumption to maintain climate control and indoor air quality (IAQ). Yet, hospital acquired infections (HAIs) afflict approximately 8% of the in-patient population and claim more than 115,000 lives each year in Europe and the U.S. alone.