scholarly journals Estimating the background ventilation rates in new-build UK dwellings – Is n50/20 appropriate?

2016 ◽  
Vol 26 (4) ◽  
pp. 502-513 ◽  
Author(s):  
David Johnston ◽  
Anne Stafford
Keyword(s):  
Preliminary Investigation ◽  
The Other ◽  
Tracer Gas ◽  
Related Factors ◽  
Change Rate ◽  
Rule Of Thumb ◽  
Air Change Rate ◽  
Ventilation Strategies ◽  
The Uk ◽  
Ventilation Rates

In the UK, a rule of thumb applied to air permeability is commonly employed when estimating background ventilation rates from pressurisation test data. However, this may lead to significant errors in estimating the infiltration rates in UK new-build dwellings, resulting in poor estimation of the dwellings in-use energy and CO2 emissions, and the adoption of ventilation strategies leading to either unacceptable indoor air quality or unnecessary energy consumption. In this paper, a preliminary investigation into the applicability of the rule of thumb is undertaken. Background ventilation rates in four new-build dwellings in the UK are determined using the tracer gas decay method and also the pressurisation (blower door) method coupled with both the conventional n50/20 and (in the UK) q50/20 rule of thumb, and Sherman’s modified rule of thumb, which takes into account other building-related factors. The conventional method overestimated the air-change rate in two of the dwellings and underestimated it in the other two dwellings. The modified rule of thumb produced comparable results for two of the dwellings, but significantly underestimated the air-change rate in the other two dwellings. These results suggest that more work needs to be done to devise appropriate climate and building-related correction factors for the UK.

scholarly journals A Discussion Regarding the Measurement of Ventilation Rates Using Tracer Gas and Decay Technique

2020 ◽  
Vol 5 (10) ◽  
pp. 85
Author(s):  
Ricardo M. S. F. Almeida ◽  
Eva Barreira ◽  
Pedro Moreira
Keyword(s):  
Cross Contamination ◽  
Single Family ◽  
Outdoor Temperature ◽  
Time Dependency ◽  
Tracer Gas ◽  
Large Variability ◽  
Change Rate ◽  
Air Change Rate ◽  
Ventilation Rates

The measurement of ventilation rates is crucial in understanding buildings’ performances, but can be a rather complex task due to the time-dependency of wind and buoyancy forces, which are responsible for the pressure differences that induce air movement across the envelope. Thus, assessing air change rate through one-time measurements during brief periods of time may not be a reliable indicator. In this paper, the variability in the measurement of ventilation rates using the decay technique was evaluated. To that end, two compartments of a typical single-family detached dwelling were selected as a case study and 132 tests were performed, considering two different boundary conditions (door closed and door open). This work allowed the large variability of the results to be highlighted, as the coefficient of variation ranged from 20% to 64%. Wind speed had a key effect on the results, especially because during the measurements indoor–outdoor temperature differences were not so significant. The possibility of using occupant-generated carbon dioxide as tracer gas was also analyzed, but problems of cross-contamination were identified.

scholarly journals Danish Dwellings with Cold Attics—Ventilation Rates and Air Exchange between Attic and Dwelling

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 64
Author(s):  
Tessa Kvist Hansen
Keyword(s):  
Mould Growth ◽  
Single Family ◽  
Tracer Gas ◽  
Change Rate ◽  
Air Change Rate ◽  
Humidity Measurements ◽  
Excess Moisture ◽  
Ventilation Rates ◽  
And Diffusion ◽  
Air Exchange

Naturally ventilated cold attics are traditional in many Danish single-family homes. The moisture balance of these attics is dependent on sufficient ventilation for removal of excess moisture. Moisture is generated in the dwelling below, and transported to attic spaces through convection and diffusion. Therefore, airtight ceilings are vital for reduction of excess moisture, which may yield mould growth in the attic. If mould spores migrate to the dwelling it can cause risk of health concerns for occupants. The presents study includes analysis of tracer gas and temperature/relative humidity measurements, in 30 dwellings/attics. The measurements yielded results of both air change rates in attics and dwellings, as well as air exchange between the two zones. Four of 30 houses, met the recommended air change rate of 0.5 h−1, and only in summer. The air change rate in the attics was found to be higher, and with larger variation compared to the dwelling. Visible mould growth was found in three attics, which all exhibited low air change rates. Air exchange between zones occurred in houses both with and without vapour barriers. The downward air exchange in summer, was however slightly larger in cases without vapour barriers. These results highlight the importance of airtight ceilings for both dwelling and attic performance.

scholarly journals Airflow as a Possible Transmission Route of Middle East Respiratory Syndrome at an Initial Outbreak Hospital in Korea

2018 ◽  
Vol 15 (12) ◽  
pp. 2757 ◽  
Author(s):  
Minki Sung ◽  
Seongmin Jo ◽  
Sang-Eun Lee ◽  
Moran Ki ◽  
Bo Choi ◽  
...  
Keyword(s):  
Middle East ◽  
Infected Patient ◽  
Close Contact ◽  
Middle East Respiratory Syndrome ◽  
High Concentration ◽  
Tracer Gas ◽  
Long Distance ◽  
Indoor Airflow ◽  
Change Rate ◽  
Air Change Rate

In this study, the results of an airflow investigation conducted on 7 June 2015 as part of a series of epidemiologic investigations at Pyeongtaek St. Mary’s Hospital, South Korea, were investigated. The study involved 38 individuals who were infected directly and indirectly with Middle East Respiratory Syndrome (MERS), by a super-spreader patient. Tracer gas experiments conducted on the eighth floor, where the initial patient was hospitalized, confirmed that the tracer gas spread to adjacent patient rooms and rooms across corridors. In particular, the experiment with an external wind direction and speed similar to those during the hospitalization of the initial patient revealed that the air change rate was 17–20 air changes per hour (ACH), with air introduced through the window in the room of the infected patient (room 8104). The tracer gas concentration of room 8110, which was the farthest room, was 7.56% of room 8104, indicating that a high concentration of gas has spread from room 8104 to rooms across the corridor. In contrast, the tracer gas was barely detected in a maternity ward to the south of room 8104, where there was no secondary infected patient. Moreover, MERS is known to spread mainly by droplets through close contact, but long-distance dispersion is probable in certain environments, such as that of a super-spreader patient hospitalized in a room without ventilation, hospitals with a central corridor type, and indoor airflow dispersion due to external wind.

Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone

2017 ◽  
Vol 115 ◽  
pp. 173-181 ◽  
Author(s):  
K.E. Anders Ohlsson ◽  
Bin Yang ◽  
Alf Ekblad ◽  
Christoffer Boman ◽  
Robin Nyström ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Rate Measurement ◽  
Stable Carbon ◽  
Tracer Gas ◽  
Change Rate ◽  
Air Change Rate

The Minimum Ventilation Intensity Research Using Selected Parameters

2013 ◽  
Vol 353-356 ◽  
pp. 3029-3033
Author(s):  
Richard Nagy ◽  
Danica Košičanová
Keyword(s):  
Ventilation System ◽  
Ventilation Rate ◽  
Cfd Simulations ◽  
Change Rate ◽  
Air Change Rate ◽  
Distribution Scheme ◽  
Air Ventilation ◽  
Ventilation Rates ◽  
The Impact ◽  
Selection Of

The air ventilation rates defined in Standard STN EN 15 251:2007 present air change rate in which the objective benefit of proper selection of ventilation system and air distribution scheme is lost (erased) in relation to IAQ [1,2]. With help of sensory evaluation in research the total minimum ventilation rate was estimated. It was reason how to determine major boundary condition (air quantity = air ventilation rate) for minimizing of responsibility size of air quantity (quantitative component of ventilation) and maximize the impact of the choice of distribution scheme and the distribution element (qualitative component of ventilation) for transfer and distribution of pollutants in research. The total air ventilation rate for next experimental measurements was established as the intersection of three air ventilation rates according to research harmonogram. This air ventilation rate was necessary to supply to occupant to experimental classroom and also as input value to CFD simulations.

The Impact of Gymnasium Form’s Tilting Side Interfaces on Natural Ventilation and Thermal Comfort of Exercise Site

2014 ◽  
Vol 587-589 ◽  
pp. 490-497
Author(s):  
Jin Li ◽  
Yuan You
Keyword(s):  
Thermal Comfort ◽  
Wind Velocity ◽  
Natural Ventilation ◽  
Change Rate ◽  
Symmetrical Mode ◽  
Air Change Rate ◽  
Window Opening ◽  
Symmetrical Model ◽  
Ventilation Strategies ◽  
The Impact

To improve air change rate and exercise site’s thermal comfort of gymnasium under natural ventilation in hot and humid areas, taking Guangzhou as an example, symmetrical model, unsymmetrical model, and unsymmetrical model with corbel table were simulated and calculated with Fluent and other software. The result indicates that, compared with symmetrical mode, unsymmetrical model and unsymmetrical model with corbel table can improve exercise site’s wind velocity and integral air change rate, and the latter model improves more. Based on unsymmetrical model with corbel table, window-opening ventilation strategies for competition are further put forward. In the end, it discusses about the influence towards thermal comfort of exercise site by natural ventilation in different form models and different use modes.

scholarly journals Developing a new passive tracer gas test for air change rate measurement

2020 ◽  
pp. 1-11
Author(s):  
Sarah L. Paralovo ◽  
Maarten Spruyt ◽  
Joris Lauwers ◽  
Rudi Swinnen ◽  
Borislav Lazarov ◽  
...  
Keyword(s):  
Passive Tracer ◽  
Rate Measurement ◽  
Tracer Gas ◽  
Change Rate ◽  
Air Change Rate
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