Swine Finishing Room Air Infiltration: Part 1. Quantification and Prediction

Abstract. Air infiltration through unplanned inlets is an integral component of any ventilation process. Air infiltration affects the quality of the room environment and can also increase winter heating costs. Precise data on air infiltration is very important in the design of animal room ventilation systems. Nineteen mechanically ventilated (negative pressure type) swine finishing rooms in Iowa were tested for their air infiltration potential. Using the data of 17 rooms, air infiltration rate through the whole room (i.e., total air infiltration, It), curtains (Ic), fans (If), and net building shell (other components, Io) were quantified. Power law equations were developed for infiltration prediction of different room configurations grouped on the basis of their construction style, age, ceiling material, curtain perimeter, and fan backdraft shutter area. All power law models reported in this study were adjusted to predict standard (sea level) infiltration rates. At 20 Pa pressure difference across the room envelope, the predicted standard It infiltration rate for the 17 rooms was 5.96±1.49 air changes per hour (ach); whereas, the predicted standard Ic, If, and Io infiltration rates were 1.49 ±1.00 ach (about 25% of It), 1.52 ±1.38 ach (about 26% of It) and 2.90 ±1.42 ach (about 49% of It), respectively. The standard It infiltration rate trended lower for rooms (n=8) from single room layout barns (5.85 ±1.66 at 20 Pa), rooms (n=8) having a non-metal ceiling (5.85 ±2.15 at 20 Pa), and rooms (n=8) aged = 13 years (5.85 ±2.15 at 20 Pa). The infiltration resistances, calculated using standard sea level infiltration rates, indicated that the curtain, fan, and other infiltration areas of swine finishing rooms changes with barn layout, age, construction material, and pressure difference. Methodology to convert measured infiltration rates to standard sea level weather conditions and to any desired room location was included. Keywords: Infiltration, Swine finishing Barns, Swine finishing rooms, Infiltration prediction, Infiltration quantification, Ventilation.

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Swine Finishing Room Air Infiltration: Part 2. Infiltration as Affected by Room Characteristics

Applied Engineering in Agriculture ◽

10.13031/aea.12559 ◽

2018 ◽

Vol 34 (4) ◽

pp. 735-745

Author(s):

Harishchandra T Jadhav ◽

Steven J Hoff ◽

Jay D Harmon ◽

Daniel S Andersen

Keyword(s):

Linear Regression ◽

Power Law ◽

Infiltration Rate ◽

The United States ◽

Design Criterion ◽

Large Variability ◽

Infiltration Rates ◽

Air Infiltration ◽

Ceiling Height ◽

The Relationship

Abstract. Data collected on 17 swine finishing rooms from the Midwest region of the United States was used to study the relationship between infiltration rate and selected room characteristics. Effect of individual room characteristics on room infiltration rate were tested by simple linear regression (SLR) while multiple linear regression (MLR) was used to develop models for improved prediction. SLR results revealed that the total (It) and other (Io; non-curtain/fan locations) swine finishing room infiltration rates were inversely related to room width and directly related to room length and ceiling height. As expected, rooms with higher curtain end pocket overlap, curtain closure overlap distance, and in excellent condition had reduced curtain infiltration (Ic). To reduce fan infiltration (If), fan and pump-out cover perimeter and fan area should be minimized. Power law equations fitted for groups of rooms were found ineffective in accounting for the large variability in infiltration rates of swine finishing rooms as compared to MLR models. MLR models developed for It and Io prediction at 10, 20, and 30 Pa pressure differences were found to improve the prediction over power law models for groups of rooms. At 20 Pa, prediction differences compared with individual room measurements for It rate using the suggested MLR model, as compared to power law models for groups of rooms, were less by at least 61%; whereas, in the case of Io rate, prediction differences compared with individual room measurements were less by at least 49%. Recommendations made in this article, with respect to the relationship between a particular room characteristic and room infiltration rate, could be used as guiding principles along with other design criterion to reduce infiltration rates in remodeled and new swine finishing rooms. Keywords: Infiltration, Swine finishing rooms, Ventilation.

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Evaluating methods for estimating whole house air infiltration rates in summer: implications for overheating and indoor air quality

International Journal of Building Pathology and Adaptation ◽

10.1108/ijbpa-06-2021-0085 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Ben M. Roberts ◽

David Allinson ◽

Kevin J. Lomas

Keyword(s):

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Infiltration Rate ◽

Estimation Methods ◽

Tracer Gas ◽

Content Type ◽

Infiltration Rates ◽

Air Infiltration ◽

Fan Pressurisation

PurposeAccurate values for infiltration rate are important to reliably estimate heat losses from buildings. Infiltration rate is rarely measured directly, and instead is usually estimated using algorithms or data from fan pressurisation tests. However, there is growing evidence that the commonly used methods for estimating infiltration rate are inaccurate in UK dwellings. Furthermore, most prior research was conducted during the winter season or relies on single measurements in each dwelling. Infiltration rates also affect the likelihood and severity of summertime overheating. The purpose of this work is to measure infiltration rates in summer, to compare this to different infiltration estimation methods, and to quantify the differences.Design/methodology/approachFifteen whole house tracer gas tests were undertaken in the same test house during spring and summer to measure the whole building infiltration rate. Eleven infiltration estimation methods were used to predict infiltration rate, and these were compared to the measured values. Most, but not all, infiltration estimation methods relied on data from fan pressurisation (blower door) tests. A further four tracer gas tests were also done with trickle vents open to allow for comment on indoor air quality, but not compared to infiltration estimation methods.FindingsThe eleven estimation methods predicted infiltration rates between 64 and 208% higher than measured. The ASHRAE Enhanced derived infiltration rate (0.41 ach) was closest to the measured value of 0.25 ach, but still significantly different. The infiltration rate predicted by the “divide-by-20” rule of thumb, which is commonly used in the UK, was second furthest from the measured value at 0.73 ach. Indoor air quality is likely to be unsatisfactory in summer when windows are closed, even if trickle vents are open.Practical implicationsThe findings have implications for those using dynamic thermal modelling to predict summertime overheating who, in the absence of a directly measured value for infiltration rate (i.e. by tracer gas), currently commonly use infiltration estimation methods such as the “divide-by-20” rule. Therefore, infiltration may be overestimated resulting in overheating risk and indoor air quality being incorrectly predicted.Originality/valueDirect measurement of air infiltration rate is rare, especially multiple tests in a single home. Past measurements have invariably focused on the winter heating season. This work is original in that the tracer gas technique used to measure infiltration rate many times in a single dwelling during the summer. This work is also original in that it quantifies both the infiltration rate and its variability, and compares these to values produced by eleven infiltration estimation methods.

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Air infiltration rates in the bedrooms of 202 residences and estimated parametric infiltration rate distribution in Guangzhou, China

Energy and Buildings ◽

10.1016/j.enbuild.2017.12.062 ◽

2018 ◽

Vol 164 ◽

pp. 219-225 ◽

Cited By ~ 20

Author(s):

Pok Lun Cheng ◽

Xiaofeng Li

Keyword(s):

Infiltration Rate ◽

Rate Distribution ◽

Infiltration Rates ◽

Air Infiltration

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The pattern of the tectonic joints and the development of the Vlychada karst show cave in Diros, Peloponnesus, Greece

10.5194/egusphere-egu21-14290 ◽

2021 ◽

Author(s):

Christos Filis ◽

Emmanuel Skourtsos ◽

Nikolaos Karalemas ◽

Vasilios Giannopoulos ◽

Ioannis Giannopoulos ◽

...

Keyword(s):

Characteristic Feature ◽

Sea Level ◽

Carbonate Rocks ◽

Meteoric Water ◽

Weather Conditions ◽

High Angle ◽

Tectonic Structures ◽

Joint System ◽

Factors Influencing ◽

Show Cave

The most characteristic feature of carbonate rocks is that they are prone to dissolution due to the meteoric water circulation which is enriched in CO2. One of the factors influencing this phenomenon is the existence of discontinuities within the mass of carbonate rocks. The Diros Vlychada show cave, on the peninsula of Mani in Peloponnese, Greece, has developed in marbles that belong to the Plattenkalk geotectonic unit. Most of the cave is flooded with water and its level changes depending on the external weather conditions and variations in sea level. The deformation of the marbles is represented by tectonic structures formed during the Lower Miocene metamorphism and their subsequent exhumation. The final uplift stage took place during the Pliocene-Quaternary and is still active. Five joints systems were distinguished:A NW-SE joint system which is subdivided into a subsystem with low-angle dips, mainly towards to the NW, related to the main foliation of the marbles and a second subsystem characterized by stretching joints of the same strike (elongated joints), which have high-angle dips, also towards the NW. The latter system intersects the former but is confined between marble bedding and does not extend to more than three beds (the bedding is defined by the first subsystem).A NW-SE striking joint system characterized by stretching joints with high-angle dips, which intersects diagonally the two previous. This system extends between more than three marble beds.Two systems show E-W and N-S strike with the first one much better expressed. Those joints have developed diagonally to the previous ones. These are mainly shear joints that intersect the first system and are propagated within many marble beds.The chambers of the cave have been developed along NW-SE and E-W directions. The first one is identified with the joint system that has been developed transversely to the strike of the marble foliation and the second in parallel with the main system of the shear joints. It is interesting that the bays forming the coastline of the Mani peninsula, have developed in an E-W direction, which coincides with both one of the growth directions of the cave and one of the joints systems, which correspond to shear joints developed during the folding of the marbles. Stalactites and stalagmites grow in a NE-SW direction that is identical to the elongated joints which form the system that is parallel to the foliation strike. Groundwater flow along these branches may be slower as these branches appear to be restricted between marble bedding.

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Spatial and Temporal Evolution of the Infiltration Characteristics of a Loess Landslide

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9010026 ◽

2020 ◽

Vol 9 (1) ◽

pp. 26 ◽

Cited By ~ 2

Author(s):

Dongdong Yang ◽

Haijun Qiu ◽

Yanqian Pei ◽

Sheng Hu ◽

Shuyue Ma ◽

...

Keyword(s):

Slope Stability ◽

Slope Failure ◽

Temporal Evolution ◽

Infiltration Rate ◽

Middle Part ◽

Loess Landslide ◽

Infiltration Rates ◽

Disturbed Soil ◽

Landslide Body ◽

Over Time

Infiltration plays an important role in influencing slope stability. However, the influences of slope failure on infiltration and the evolution of infiltration over time and space remain unclear. We studied and compared the infiltration rates in undisturbed loess and disturbed loess in different years and at different sites on loess landslide bodies. The results showed that the average initial infiltration rate in a new landslide body (triggered on 11 October 2017) were dramatically higher than those in a previous landslide body (triggered on 17 September 2011) and that the infiltration rates of both landslide types were higher than the rate of undisturbed loess. The initial infiltration rate in the new landslide body sharply decreased over the 4–5 months following the landslide because of the appearance of physical crusts. Our observations indicated that the infiltration rate of the disturbed soil in a landslide evolved over time and that the infiltration rate gradually approached that of undisturbed loess. Furthermore, in the undisturbed loess, both the initial and quasi-steady infiltration rates were slightly higher in the loess than in the paleosol, and in the previous landslide body, the infiltration rate was highest in the upper part, intermediate in the middle part, and lowest in the lower part. This study can help us to better understand the evolution process of infiltration in undisturbed loess, previous landslides, and new landslides.

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A Sensitivity Analysis of Simulated Infiltration Rates to Uncertain Discretization in the Moisture Content Domain

Water ◽

10.3390/w11061192 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1192

Author(s):

Lulu Liu ◽

Han Yu

Keyword(s):

Moisture Content ◽

Nonlinear Dynamical System ◽

Infiltration Rate ◽

Hydrologic Model ◽

Water Infiltration ◽

Nonlinear Dynamical ◽

Pore Sizes ◽

Infiltration Rates ◽

The Difference ◽

Region Scale

An unconditionally mass conservative hydrologic model proposed by Talbot and Ogden provides an effective and fast technique for estimating region-scale water infiltration. It discretizes soil moisture content into a proper but uncertain number of hydraulically interacting bins such that each bin represents a collection of pore sizes. To simulate rainfall-infiltration, a two-step alternating process runs until completion; and these two steps are surface water infiltration into bins and redistribution of inter-bin flow. Therefore, a nonlinear dynamical system in time is generated based on different bin front depths. In this study, using rigorous mathematical analysis first reveals that more bins can produce larger infiltration fluxes, and the overall flux variation is nonlinear with respect to the number of bins. It significantly implies that a greater variety of pore sizes produces a larger infiltration rate. An asymptotic analysis shows a finite change in infiltration rates for an infinite number of bins, which maximizes the heterogeneity of pore sizes. A corollary proves that the difference in the predicted infiltration rates using this model can be quantitatively bounded under a specific depth ratio of the deepest to the shallowest bin fronts. The theoretical results are demonstrated using numerical experiments in coarse and fine textured soils. Further studies will extend the analysis to the general selection of a suitable number of bins.

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In-Flight Hypoxemia in a Tracheostomy-Dependent Infant

Case Reports in Anesthesiology ◽

10.1155/2017/3210473 ◽

2017 ◽

Vol 2017 ◽

pp. 1-5

Author(s):

Jason Quevreaux ◽

Christopher Cropsey

Keyword(s):

Sea Level ◽

Healthcare Providers ◽

Barometric Pressure ◽

Federal Aviation Administration ◽

Anesthesia Resident ◽

Cardiac Pathology ◽

Mechanically Ventilated ◽

Good Samaritan ◽

Medical Supplies ◽

Commercial Flight

Millions of passengers board commercial flights every year. Healthcare providers are often called upon to treat other passengers during in-flight emergencies. The case presented involves an anesthesia resident treating a tracheostomy-dependent infant who developed hypoxemia on a domestic flight. The patient had an underlying congenital muscular disorder and was mechanically ventilated while at altitude. Although pressurized, cabin barometric pressure while at altitude is less than at sea level. Due to this environment patients with underlying pulmonary or cardiac pathology might not be able to tolerate commercial flight. The Federal Aviation Administration (FAA) has mandated a specific set of medical supplies be present on all domestic flights in addition to legislature protecting “Good Samaritan” providers.

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Effects of earthworm communities on water infiltration in wet soils with energy crops

10.5194/egusphere-egu2020-7628 ◽

2020 ◽

Author(s):

Lena Wöhl ◽

Stefan Schrader

Keyword(s):

Ecosystem Services ◽

Ecological Impact ◽

Live Weight ◽

Allyl Isothiocyanate ◽

Infiltration Rate ◽

Energy Crops ◽

Water Infiltration ◽

Energy Crop ◽

Negative Effects ◽

Infiltration Rates

Maize (Zea mays) is the most commonly cultivated energy crop throughout Europe. However, its cultivation has severe negative effects such as loss of biodiversity and its delivery of ecosystem services, soil compaction and enhanced greenhouse gas emissions. These negative effects tend to be even more pronounced in wet soils such as pseudogleys. As an alternative to annual maize, the perennial cup plant (Silphium perfoliatum) is known to produce a similar yield, especially under waterlogging conditions, while management impacts of its cultivation are assumed to be less harmful to soil biota. Therefore, the aim of the present study was to quantify the provision of ecosystem services (here: control of the soil water balance) delivered by earthworm communities in wet soils under cultivation of cup plant compared with maize and to assess the ecological impact of both energy crops.Fieldwork was conducted cup plant and maize fields (n = 4) in South Western Germany in spring and autumn 2019. The overall soil type was pseudo gleyic luvisol. All fields are managed for commercial purposes by farmers in the area. Sampling included earthworm extraction with allyl isothiocyanate (AITC) while the infiltration rate was measured simultaneously. Afterwards, hand sorting completed the earthworm sampling. Earthworm species, their abundance and biomass (live weight) were determined.On average, earthworm abundance and biomass were higher in cup plant fields than in maize fields. In addition, variations in earthworm communities were found. While endogeic earthworms, especially of the genus Aporrectodea, were present in all fields, anecic earthworms were more abundant in cup plant fields. Higher infiltration rates were measured in maize fields. Hints to a correlation between the infiltration rates and the functional earthworm groups were found.Our results suggest that cup plant fields host overall more diverse earthworm communities. These communities are able to produce a wider range of ecosystem services, even though the link between the infiltration and the crops studied in this stud is not yet validated.

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