Exchange airflows through doorways induced by door opening and occupant movement

Petri Kalliomäki

Exchange airflows through doorways induced by door opening and occupant movement

Julkaisun otsikon käännös: Oviaukon ilmavirtaukset oven avauksen ja kulun seurauksena

Petri Kalliomäki

Energia- ja konetekniikan laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Potilaat, joilla on tai joilla epäillään olevan ilmavälitteisesti leviävä tartuntatauti, sijoitetaan alipaineisiin eristystiloihin taudinaiheuttajien leviämisen estämiseksi. Tästä huolimatta ilmaa ja epäpuhtauksia voi kulkeutua ulos eristystilasta. Esimerkiksi oven avaamisen ja sitä seuraavan kulun seurauksena ilmaa (ja ilmavälitteisiä epäpuhtauksia) voi kulkeutua oviaukon kautta ulos eristystilasta. Onkin arvioitu, että oven avaus ja kulku oviaukosta olisivat yksi merkittävimmistä tekijöistä ilmavälitteisten infektioiden leviämiselle eristystiloista. Tämän väitöskirjan tavoitteena on tutkia oven avauksen ja oviaukosta kulkemisen aiheuttamia virtauskuvioita, -rakenteita ja huoneesta toiseen kulkeutuvan ilman määrää. Keskeisenä tavoitteena oli tarkastella sarana- ja liukuovien aiheuttamia ilmiöitä ja niiden eroja. Tavoitteena oli tarkastella myös muita virtauksiin vaikuttavia tekijöitä, kuten esimerkiksi oven avausaikaa (3-8 s), aukioloaikaa (2-25 s), kulkua (1 m/s), ilmanvaihtoa (0-12 1/h), paine-eroa (0-20 Pa), lämpötilaeroa (0-3 °C) jne. Lisäksi yhtenä tavoitteena oli tutkia tehostetun nettovirtauksen vaikutusta oviaukon kautta leviävän ilmamäärän vähentämiseksi. Virtausilmiöitä tutkittiin savuvisualisoinnein, merkkikaasumittauksin ja CFD-simuloinnein, joiden avulla voitiin luoda yksityiskohtainen kuva eri tilanteista. Tutkimuksessa tehdyt kokeet suoritettiin laboratorioympäristössä, johon oli rakennettu yksinkertainen sairaalan eristystilamalli. Ihmiskulkua oviaukosta simuloitiin realistisen kokoisella mallinukella. Tutkimuksen tulokset osoittivat, että oven avauksen seurauksena oviaukon kautta kulkeutui huomattava määrä ilmaa huoneesta toiseen (0,27-2,42 m3 riippuen tutkittavasta tilanteesta). Useat tekijät vaikuttivat virtauksiin, mutta merkittävimmät olivat: ovityyppi, oven aukioloaika, kulku oviaukosta, lämpötilaero ja tehostettu nettovirtaus. Mittauksien mukaan liukuoven avauksen seurauksena oviaukon kautta kulkeutui huomattavasti vähemmän ilmaa (36-79 %) verrattuna saranaoven tapaukseen. Myös tehostettu nettovirtaus oviaukon kautta pienensi huomattavasti oviaukon kautta karkaavan ilman määrää. Esimerkiksi 90 L/s ja 190 L/s ilmavirrat oviaukon kautta (kohti eristystilaa) vähensivät sulkutilaan leviävän ilman määrää vastaavasti 38 % ja 60 % verrattuna tilanteeseen ilman tehostettua nettovirtausta. Toisaalta jo 2 °C lämpötilaero lisäsi ilman kulkeutumista oviaukon kautta huomattavasti, 41 % saranaoven tapauksessa ja 304 % liukuoven tapauksessa. Lisäksi kulku ja oven aukioloaika lisäsivät karkaavan ilman määrää mutta oven avausnopeudella ei havaittu olevan suurta vaikutusta siihen. Väitöskirjan tulokset korostavat liukuovien ja tehostetun nettovirtauksen käyttöä oviaukkojen virtausten hallinnassa. Menetelmien soveltaminen vanhoissa sairaalarakennuksissa voi olla haastavaa, mutta ne voidaan ottaa huomioon suunniteltaessa uusia ja peruskorjatessa vanhoja rakennuksia.

Julkaisun otsikon käännös	Oviaukon ilmavirtaukset oven avauksen ja kulun seurauksena
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Kosonen, Risto, Vastuuprofessori Wei-Tze Tang, Julian, Ohjaaja, Ulkoinen henkilö
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-0274-1
Sähköinen ISBN	978-952-64-0275-8
Tila	Julkaistu - 2021
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

oven avaus
kulku
ilmavirta
epäpuhtauksien leviäminen
eristystila

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-64-0275-8

Siteeraa tätä

@phdthesis{2043460188fa4636a7eeddfe8bc9eccb,

title = "Exchange airflows through doorways induced by door opening and occupant movement",

abstract = "In healthcare settings, patients with infectious airborne diseases are typically placed in negative pressure isolation rooms to reduce the spreading of the infections. Nevertheless, containment failures can still happen, and it has been assessed that the combined effect of door opening and occupants movement through the doorway can be among the most relevant factors causing the containment failures in hospital isolation rooms. The aim of this thesis was to study the air volume exchange and airflow patterns across an isolation room doorway generated by door opening and occupant motion. The main focus of the study was on examining the differences between flows induced by hinged and sliding doors. The effects of several factors like door opening time (3-8 s), hold open time (2-25 s), passage (1 m/s) through the doorway, ventilation rate (0-12 ACH), pressure difference (0-20 Pa), temperature difference (0-3 °C) etc. on the exchange flows were investigated. The effect of directional airflow (net flow) was examined as a potential solution for reducing the contaminant escape through the doorway. Smoke visualizations, tracer gas measurements and CFD-simulations were used to examine the air volume exchange and airflow patterns across the doorway. All the experiments were carried out in a controlled laboratory environment consisting of a full-scale isolation room model. Occupant movement throught the doorway was simulated with a moving manikin in the experiments. The results show that the door opening generated a notable air volume exchange across the doorway (0.27-2.42 m3 depending on the examined case). Several factors affected the magnitude of these exchange flows, the clearest being the door type, door hold-open time, manikin passage,temperature difference and directional airflow. The sliding door opening was found to induce substantially smaller air exchange across the doorway compared to the hinged door. The reduction of the air volume migration with the sliding door varied between 36-79 % compared to the hingeddoor induced exchange. The directional airflow across the doorway reduced the air volume migration substantially as well. The reduction was 38 % and 60 % with 90 L/s and 190 L/s directional airflow through the doorway respectively compared to reference case without notable directional airflow (only the hinged door type was tested). On the other hand, even a small temperature difference (2 °C) increased the air volume transfer notably, i.e. by 41 % and 304 % with the hinged and sliding doors respectively. Also, the manikin passage and door hold-open times were found to increase the exchange flows. Door opening time was not found to affect the air volume transfer notably. The findings emphasize the effectiveness of sliding doors and the directional airflow in reducing the escape of contaminants through doorways induced by door operation. Even though utilization of sliding doors and directional airflows might not be directly feasible in old buildings, the installations should be at least considered when constructing new hospitals or remodeling the old.",

keywords = "door opening, occupant movement, airflow, contaminant dispersion, isolation room, oven avaus, kulku, ilmavirta, ep{\"a}puhtauksien levi{\"a}minen, eristystila, door opening, occupant movement, airflow, contaminant dispersion, isolation room",

author = "Petri Kalliom{\"a}ki",

year = "2021",

language = "English",

isbn = "978-952-64-0274-1",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "21",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Exchange airflows through doorways induced by door opening and occupant movement

AU - Kalliomäki, Petri

PY - 2021

Y1 - 2021

N2 - In healthcare settings, patients with infectious airborne diseases are typically placed in negative pressure isolation rooms to reduce the spreading of the infections. Nevertheless, containment failures can still happen, and it has been assessed that the combined effect of door opening and occupants movement through the doorway can be among the most relevant factors causing the containment failures in hospital isolation rooms. The aim of this thesis was to study the air volume exchange and airflow patterns across an isolation room doorway generated by door opening and occupant motion. The main focus of the study was on examining the differences between flows induced by hinged and sliding doors. The effects of several factors like door opening time (3-8 s), hold open time (2-25 s), passage (1 m/s) through the doorway, ventilation rate (0-12 ACH), pressure difference (0-20 Pa), temperature difference (0-3 °C) etc. on the exchange flows were investigated. The effect of directional airflow (net flow) was examined as a potential solution for reducing the contaminant escape through the doorway. Smoke visualizations, tracer gas measurements and CFD-simulations were used to examine the air volume exchange and airflow patterns across the doorway. All the experiments were carried out in a controlled laboratory environment consisting of a full-scale isolation room model. Occupant movement throught the doorway was simulated with a moving manikin in the experiments. The results show that the door opening generated a notable air volume exchange across the doorway (0.27-2.42 m3 depending on the examined case). Several factors affected the magnitude of these exchange flows, the clearest being the door type, door hold-open time, manikin passage,temperature difference and directional airflow. The sliding door opening was found to induce substantially smaller air exchange across the doorway compared to the hinged door. The reduction of the air volume migration with the sliding door varied between 36-79 % compared to the hingeddoor induced exchange. The directional airflow across the doorway reduced the air volume migration substantially as well. The reduction was 38 % and 60 % with 90 L/s and 190 L/s directional airflow through the doorway respectively compared to reference case without notable directional airflow (only the hinged door type was tested). On the other hand, even a small temperature difference (2 °C) increased the air volume transfer notably, i.e. by 41 % and 304 % with the hinged and sliding doors respectively. Also, the manikin passage and door hold-open times were found to increase the exchange flows. Door opening time was not found to affect the air volume transfer notably. The findings emphasize the effectiveness of sliding doors and the directional airflow in reducing the escape of contaminants through doorways induced by door operation. Even though utilization of sliding doors and directional airflows might not be directly feasible in old buildings, the installations should be at least considered when constructing new hospitals or remodeling the old.

AB - In healthcare settings, patients with infectious airborne diseases are typically placed in negative pressure isolation rooms to reduce the spreading of the infections. Nevertheless, containment failures can still happen, and it has been assessed that the combined effect of door opening and occupants movement through the doorway can be among the most relevant factors causing the containment failures in hospital isolation rooms. The aim of this thesis was to study the air volume exchange and airflow patterns across an isolation room doorway generated by door opening and occupant motion. The main focus of the study was on examining the differences between flows induced by hinged and sliding doors. The effects of several factors like door opening time (3-8 s), hold open time (2-25 s), passage (1 m/s) through the doorway, ventilation rate (0-12 ACH), pressure difference (0-20 Pa), temperature difference (0-3 °C) etc. on the exchange flows were investigated. The effect of directional airflow (net flow) was examined as a potential solution for reducing the contaminant escape through the doorway. Smoke visualizations, tracer gas measurements and CFD-simulations were used to examine the air volume exchange and airflow patterns across the doorway. All the experiments were carried out in a controlled laboratory environment consisting of a full-scale isolation room model. Occupant movement throught the doorway was simulated with a moving manikin in the experiments. The results show that the door opening generated a notable air volume exchange across the doorway (0.27-2.42 m3 depending on the examined case). Several factors affected the magnitude of these exchange flows, the clearest being the door type, door hold-open time, manikin passage,temperature difference and directional airflow. The sliding door opening was found to induce substantially smaller air exchange across the doorway compared to the hinged door. The reduction of the air volume migration with the sliding door varied between 36-79 % compared to the hingeddoor induced exchange. The directional airflow across the doorway reduced the air volume migration substantially as well. The reduction was 38 % and 60 % with 90 L/s and 190 L/s directional airflow through the doorway respectively compared to reference case without notable directional airflow (only the hinged door type was tested). On the other hand, even a small temperature difference (2 °C) increased the air volume transfer notably, i.e. by 41 % and 304 % with the hinged and sliding doors respectively. Also, the manikin passage and door hold-open times were found to increase the exchange flows. Door opening time was not found to affect the air volume transfer notably. The findings emphasize the effectiveness of sliding doors and the directional airflow in reducing the escape of contaminants through doorways induced by door operation. Even though utilization of sliding doors and directional airflows might not be directly feasible in old buildings, the installations should be at least considered when constructing new hospitals or remodeling the old.

KW - door opening

KW - occupant movement

KW - airflow

KW - contaminant dispersion

KW - isolation room

KW - oven avaus

KW - kulku

KW - ilmavirta

KW - epäpuhtauksien leviäminen

KW - eristystila

KW - door opening

KW - occupant movement

KW - airflow

KW - contaminant dispersion

KW - isolation room

M3 - Doctoral Thesis

SN - 978-952-64-0274-1

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Exchange airflows through doorways induced by door opening and occupant movement

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

Sormenjälki

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