Air flow through cracks

Baker, Paul; Sharples, Steve; Ward, Ian

doi:10.1016/0360-1323(87)90022-9

Cited by 84 publications

(38 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Few studies have been published focusing on leakage flow in vehicles. However, leakage flow from building cracks has been studied and can be calculated using the following equation (Baker et al 1987).…”

Section: Mechanical Airflow (Q S ) and Leakage Airflow (Q L )mentioning

confidence: 99%

Quantitative Analysis of the Parameters Affecting In-Cabin to On-Roadway (I/O) Ultrafine Particle Concentration Ratios

Zhu

2009

Aerosol Science and Technology

View full text Add to dashboard Cite

A mass-balance indoor particle dynamic model was adopted and modified to investigate how on-roadway ultrafine particle (UFP, diameter < 100 nm) concentrations and vehicle ventilation settings affect UFP levels inside vehicles. The model was first parameterized focusing on a mechanistic, simulation-based interpretation of in-cabin data reported in Zhu et al. Under condition (3), the effects of penetration factor, deposition coefficient, and vehicle speed were comparable. The modeled I/O ratio was inversely proportional to the airflow rate from mechanical ventilation in the whole range (0-360 m 3 h −1 ) with 10-20% influence depending on the particle size.

show abstract

Section: Mechanical Airflow (Q S ) and Leakage Airflow (Q L )mentioning

confidence: 99%

Quantitative Analysis of the Parameters Affecting In-Cabin to On-Roadway (I/O) Ultrafine Particle Concentration Ratios

Zhu

2009

Aerosol Science and Technology

View full text Add to dashboard Cite

show abstract

“…This model employs a quadratic relationship of the form P = aQ + bQ² where Q is the volume flow rate [Baker, Sharples, and Ward 1987]. CONTAM uses the mass flow version of that formula: P = aF + bF² where P is the pressure drop and F is the mass flow rate.…”

Section: Quadratic Model: Crack Descriptionmentioning

confidence: 99%

“…Baker, Sharples, and Ward [Baker 1987] indicate that infiltration openings can be more accurately modeled by a quadratic relationship of the form (37) This form can be used as an airflow element by solving the quadratic equation for F (= Q). Letting a = A/ and b = B/ 2 allows equations (37) to be rewritten as (38) These quadratic equations solve as (39) with the partial derivatives given by (40) Equations (39) require that b be nonzero to prevent a division by zero and equations (40) requires that a be nonzero to prevent a division by zero as F goes to zero.…”

Section: Quadratic Flow Elementsmentioning

confidence: 99%

“…Theoretical relationships have been developed between the coefficients A and B of the quadratic airflow element model and the physical characteristics of the openings [Baker 1987]. These are (45) where = viscosity, = density, z= distance along the direction of flow, d= crack width, L= crack length, and C= 1.5 + number of bends in the flow path.…”

Section: Crack Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

CONTAM User Guide and Program Documentation Version 3.2

Dols¹,

Polidoro²

2015

125

View full text Add to dashboard Cite

This manual describes the computer program CONTAM version 3.2, developed by NIST. CONTAM is a multizone indoor air quality and ventilation analysis program designed to help determine airflows, contaminant concentrations, and personal exposure in buildings. Airflows include infiltration, exfiltration, and room-to-room airflow rates and pressure differences in building systems, and can be driven by mechanical means, wind pressures acting on the exterior of the building, and buoyancy effects induced by temperature differences between zones, including the outdoors. Contaminant concentrations include the transport and fate of airborne contaminants, due to airflow, chemical and radio-chemical transformation, adsorption and desorption to building materials, filtration, and deposition to and resuspension from building surfaces. Personal exposure includes the exposure of building occupants to airborne contaminants, for eventual risk assessment.CONTAM can be useful in a variety of applications. Its ability to calculate building airflow rates and relative pressures between zones of the building is useful for assessing the adequacy of ventilation rates in a building, for determining the variation in ventilation rates over time, for determining the distribution of ventilation air within a building, for estimating the impact of envelope air-tightening efforts on infiltration rates, and for evaluating the energy impacts of building airflows. The program has also been used extensively for the design and analysis of smoke management systems. The prediction of contaminant concentrations can be used to determine the indoor air quality performance of buildings before they are constructed and occupied, to investigate the impacts of various design decisions related to ventilation system design and building material selection, to evaluate indoor air quality control technologies, and to assess the indoor air quality performance of existing buildings. Predicted contaminant concentrations can also be used to estimate personal exposure based on occupancy patterns. Version 2.0 contained several new features including: non-trace contaminants, practically unlimited number of contaminants, contaminant-related libraries, separate weather and ambient contaminant files, building controls, scheduled zone temperatures, improved solver to reduce simulation times and several user interface related features to improve usability. Version 2.1 introduced more new features including the ability to account for spatially varying external contaminants and wind pressures at the building envelope, more new control elements, particlespecific contaminant properties, total mass released calculations and detailed program documentation. Version 2.4 introduced two new deposition sink models, a one-dimensional convection/diffusion contaminant model for ducts and user-selectable zones, new contaminant filter models, control super nodes, super filters, a duct balancing tool, building pressurization and model validity tests and several other usability enhanceme...

show abstract

“…The building has a plan area of 8.7 m x 10.4 m; the basement and footers represent standard construction practice and are depicted in Figure 2 (a). A 1 mm L-shaped crack provides the route for advective entry of radon into the basement Advective flow through this channel is modeled with the equation (Baker et al, 1987) ( 1) where p is the disturbance pressure (pa), ex and f3 are empirically determined constants that are functions of the crack geometry, and vis the soil-gas velocity vector (m sol). For this study ex is 1.2xlO-3 m 3 s kg-l and f3 is 0.035 s mol (Gadgil et al, 1991).…”

Section: House Substructure and Soil Characteristicsmentioning

confidence: 99%