Measurement of ventilation and airborne infection risk in large naturally ventilated hospital wards

Gilkeson, Carl; Camargo‐Valero, Miller Alonso; Pickin, L.E.; Noakes, Catherine

doi:10.1016/j.buildenv.2013.03.006

Cited by 77 publications

(99 citation statements)

References 42 publications

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“…It is reported that airborne infection risk in large naturally ventilated hospital wards increases when ventilation rates decrease (Gilkeson et al 2013). Sundell et al (2011) referred that multiple health endpoints show similar relationships with ventilation rate and that there is biological plausibility for an association of health outcomes with ventilation rates.…”

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confidence: 99%

Numerical evaluation of ventilation performance in children day care centres

et al. 2014

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Modelling of ventilation is strongly dependent on the physical characteristics of the building of which precise evaluation is a complex and time consuming task. In the frame of a research project, two children day care centres (CDCC) have been selected in order to measure the envelope air permeability, the flow rate of mechanical ventilation systems and indoor and outdoor temperature. The data obtained was used as input to the computer code CONTAM for ventilation simulations. The results obtained were compared with direct measurements of ventilation flow from short term measurements with CO2 tracer gas and medium term measurements with perfluorocarbon tracer (PFT) gas decay method. After validation, in order to analyse the main parameters that affect ventilation, the model was used to predict the ventilation rates for a wide range of conditions. The purpose of this assessment was to find the best practices to improve natural ventilation. A simple analytical method to predict the ventilation flow rate of rooms is also presented. The method is based on the estimation of wind effect on the room through the evaluation of an average factor ( ) ¥ * 2 Δ / P ρ and on the assessment of relevant cross section of gaps and openings combined in series or in parallel. It is shown that it may be applied with acceptable accuracy for this type of buildings when ventilation is due essentially to wind action. Keywordschildren day care centre, air permeability, tracer gas, PFT,

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Section: List Of Symbolsmentioning

confidence: 99%

Numerical evaluation of ventilation performance in children day care centres

et al. 2014

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“…Additionally, the transmission of pathogens David Head School of Computing, University of Leeds, UK. e-mail: d.head@leeds.ac.uk 1 between individuals is facilitated by transport through artificial water lines and airways where biofilms lay dormant, detaching cells under a combination of genetic control and flow-imposed mechanical stresses to colonise new biofilms downstream [16,38] Fig. 1 Schematic representation of some issues relevant to biofilm mechanics.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrodynamic flow is known to affect biofilm formation and propagation in dental unit water lines [100], catheters (both urinary tract and intravascu-lar) and hemodialysis machines [36,50,83,103], bile drains, stents, and voice prostheses [16]. In addition, the response to surface airflow and known airborne dispersal modes should be considered in the design of nosocomial ventilation systems [38,83]. Flow is also a key consideration for industrial biofilms as overgrowth can cause clogging in biofilm reactors [52,93], although here the goal is to maximise metabolic efficacy rather than microbial eradication.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical Analysis of Infectious Biofilms

Head

2016

Biophysics of Infection

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The removal of infectious biofilms from tissues or implanted devices and their transmission through fluid transport systems depends in part of the mechanical properties of their polymeric matrix. Linking the various physical and chemical microscopic interactions to macroscopic deformation and failure modes promises to unveil design principles for novel therapeutic strategies targeting biofilm eradication, and provide a predictive capability to accelerate the development of devices, water lines etc. that minimise microbial dispersal. Here our current understanding of biofilm mechanics is appraised from the perspective of biophysics, with an emphasis on constitutive modelling that has been highly successful in soft matter. Fitting rheometric data to viscoelastic models has quantified linear and non-linear stress relaxation mechanisms, how they vary between species and environments, and how candidate chemical treatments alter the mechanical response. The rich interplay between growth, mechanics and hydrodynamics is just becoming amenable to computational modelling and promises to provide unprecedented characterisation of infectious biofilms in their native state.

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“…It is not evident from historical or contemporary literature that this area of opening has been fully studied in terms of its impact on adequate ventilation rates, specifically for dilution or airborne pollutants of pathogens. There is nevertheless research evidence pointing towards substantial increase in risk of cross-infection when such windows in multi-bed wards are closed in winter to save heating energy [7]. In summer, the current and long-term potential for overheating of naturally ventilated wards have also been shown [8] implying that better natural ventilation is desirable.…”

Section: Introductionmentioning

confidence: 99%

The Design and Simulation of Natural Personalised Ventilation (NPV) System for Multi-Bed Hospital Wards

Adamu

Price

2015

Buildings

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Adequate ventilation is necessary for thermal comfort and reducing risks from infectious bio-aerosols in hospital wards, but achieving this with mechanical ventilation has carbon and energy implications. Natural ventilation is often limited to window-based designs whose dilution/mixing effectiveness are subject to constraints of wind speed, cross ventilation, and in the case of hospital wards, proximity of patients to external walls. A buoyancy-driven natural ventilation system capable of achieving dilution/mixing was shown to be feasible in a preceding study of novel system called natural personalised ventilation (NPV). This system combined both architecture and airflow engineering principles of space design and buoyancy and was tested and validated (salt-bath experiment) for a single bed ward. This research extends the previous work and is proof-of-concept on the feasibility of NPV system for multi-bed wards. Two different four-bed ward types were investigated of using computational fluid dynamics (CFD) simulations under wind-neutral conditions. Results predict that NPV system could deliver fresh air to multiple patients, including those located 10 m away from external wall, with absolute flow rates of between 32 L·s for each patient/bed. Compared to same wards simulated using window design, ingress of airborne contaminants into patients' breathing zone and summer overheating potential were minimised, while overall ward dilution was maximised. Findings suggest the NPV has potentials for enabling architects and building service engineers to decouple airflow delivery from the visualisation and illumination responsibilities placed upon windows. OPEN ACCESSBuildings 2015, 5 382

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Measurement of ventilation and airborne infection risk in large naturally ventilated hospital wards

Cited by 77 publications

References 42 publications

Numerical evaluation of ventilation performance in children day care centres

Numerical evaluation of ventilation performance in children day care centres

Biomechanical Analysis of Infectious Biofilms

The Design and Simulation of Natural Personalised Ventilation (NPV) System for Multi-Bed Hospital Wards

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