Effects of air exchange rate, particle size and injection place on particle concentrations within a reduced-scale room

Faulkner, William B.; Memarzadeh, Farhad; Riskowski, G. L.; Kalbasi, Ahmad; Chang, Audrey Chingzu

doi:10.1016/j.buildenv.2015.04.034

Cited by 22 publications

(29 citation statements)

References 38 publications

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“…The recommended minimum value of ACH is very similar in UNE 100713 and ASHRAE Standard 170, however, this parameter is not specified in EN 16244-2. On the one hand, increasing the amount of fresh air impelled improves dilution effectiveness [53] but, on the other hand, it does not guarantee an SSI rate decrease and, nevertheless, operating costs are always raised [54]. Infection hazard is reduced by controlling air movement pattern [52,55] which leads to an equipment expenditure and operating costs reduction.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of HVAC Design Parameters in High-Performance Hospital Operating Theatres

Sánchez-Barroso

García-Sanz-Calcedo

2019

Sustainability

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Unidirectional flow air-conditioning systems are suitable for achieving indoor air quality required in high-performance operating rooms (organ transplants, cardiac surgery, aorta, orthopedic, burns, etc.). This paper analyzes indoor environmental conditions and technical and hygienic requirements for the design of heating, ventilation, and air-Conditioning (HVAC) systems for high-performance operating theatres. The main standards applicable to this type of operating rooms were compiled. Standard UNE 100713:2015, ASHRAE Standard 170-2017, and the European pre-norm EN 16244 were analyzed. A case study shows the lack of uniformity in design criteria and their ranges of values, which generates different design approaches. It was concluded that using these standards applicable to high-performance operating rooms leads to very different indoor environmental conditions for patients and medical personnel—air velocity profiles, air movement pattern, temperature, relative humidity gradients, and pressure stratification. Computational fluid dynamics (CFD) studies have been shown to detect areas of haven that favor microbiological load accumulation. In this way, it is possible to define cleaning protocols to attend these anomalies in a preventive way.

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Section: Discussionmentioning

confidence: 99%

Evaluation of HVAC Design Parameters in High-Performance Hospital Operating Theatres

Sánchez-Barroso

García-Sanz-Calcedo

2019

Sustainability

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“…In the engineering field, the airborne transmission between occupants indoors is usually investigated using both experiments and Computational fluid dynamics (CFD) methods [ 20 ]. Experimental methods include quantitative measurement of the concentration field [ 21 , 22 ] and imaging visualization of expiratory flows [ 11 , 12 ]. Chamber experiments using breathing thermal manikins and ancillary machines [ 23 , 24 ] have been the primary method of investigating airborne transmission between occupants and quantifying the risk of cross-infection.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Three Ventilation Strategies in a prefabricated COVID-19 inpatient ward

Ren

Wang

Liu

et al. 2021

Building and Environment

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Prefabricated inpatient wards have been proven to be an efficient alternative to quickly extend the caring capacity for patients. In this study, three typical ventilation strategies were studied using computational fluid dynamics in a prefabricated Coronavirus disease 2019 double-patient ward. Pollutants are the respiratory droplets and aerosols injected from two manikins. They are modelled as particles with different diameters (3 μm, 6 μm, 12 μm, 20 μm, 45 μm and 175 μm) by the Eulerian–Lagrangian model. Three ventilation strategies with an identical air change rate of 12.3 h −1 but different layouts of inlets and outlets are implemented. The flow field, flow structures and particle trajectories have been analysed and compared among the three ventilation strategies. The fate of particles is analysed and compared quantitatively. It is found that small particles (<20 μm) can move along with the main flow streams. Most of them are removed by ventilation to the outlet(s). Large particles (>45 μm) cannot move with the flow streams over a long path. Most of them deposit on solid surfaces in different regions of the ward in each ventilation strategy. Health workers should pay close attention to these polluted areas. Targeted cleaning of the polluted areas is necessary in a prefabricated inpatient ward. To promote the removal of some large particles (e.g., 45 μm) by the outlet(s), the outlet(s) should be installed inside the landing area of large particles and close to the polluted source(s).

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“…Faulkner vd. [8,9] • Genel karakter olarak, artan HDK değeri ile ortalama konsantrasyon miktarı azalsa da azalma oranı ana akış bölgesi içerisinde yer alan kirletici durumunda sınırlı bir seviyede kalmakta diğer bölgelerde yer alan kirletici kaynakları durumunda ise daha belirgin olmaktadır.…”

Section: Gi̇ri̇ş (Introduction)unclassified

Hava Değişim Katsayısının Kirletici Uzaklaştırma Performansına Etkisinin İncelenmesi

2021

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Bu çalışmada, hava değişim katsayının partikül dağılımına etkisi farklı kirletici kaynak konumları için deneysel ve sayısal olarak incelenmiştir. Deneysel çalışma küçük ölçekli bir model oda üzerinde izotermal akış şartları için yürütülmüş ve kirletici olarak 0,5 µm ebatında partiküller kullanılmıştır. Partikül hareketleri, Lagrange yaklaşımı esas alınarak bir hesaplamalı akışkanlar dinamiği (HAD) yazılımı olan ANSYS Fluent programında modellenmiştir. Ana akış bölgesi dışında yer alan kirleticilerin 12 kata kadar daha yüksek konsantrasyon değerlerine yol açtığı görülmüştür. Bununla beraber, hava değişim katsayısındaki artışın bu bölgedeki kirletici konsantrasyonunu %75 oranında azalttığı tespit edilmiştir. Anahtar Kelimeler: Hava değişim katsayısı (HDK), partikül dağılımı, kirletici uzaklaştırma.

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Effects of air exchange rate, particle size and injection place on particle concentrations within a reduced-scale room

Cited by 22 publications

References 38 publications

Evaluation of HVAC Design Parameters in High-Performance Hospital Operating Theatres

Evaluation of HVAC Design Parameters in High-Performance Hospital Operating Theatres

Numerical Study of Three Ventilation Strategies in a prefabricated COVID-19 inpatient ward

Hava Değişim Katsayısının Kirletici Uzaklaştırma Performansına Etkisinin İncelenmesi

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