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The Auditor’s Tools and How to Use Them
Published in Stan Harbuck, Donna Harbuck, Residential Energy Auditing and Improvement, 2021
So, blower doors are used to create an artificially high-pressure difference between the inside and outside of the home to determine how leaky a home is. Blower door leakage numbers can then be used to calculate an estimated leakage in the home under natural conditions. A blower door test is used for at least two very important reasons: determining the air leakage rate of the home at -50 Pascals and determining the location of air leaks in the home.
Infiltration and Natural Ventilation
Published in T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl, Heating and Cooling of Buildings, 2016
T. Agami Reddy, Jan F. Kreider, Peter S. Curtiss, Ari Rabl
There is another problem in applying Equation 6.20 to buildings: The width of an opening can change with pressure. Blower door tests (described in Section 6.3 on actual walls have shown that the apparent leakage area can be significantly higher for overpressurization than for underpressurization; external pressure tends to compress the cracks of a building (Lydberg and Honarbakhsh, 1989). Blower door tests do not directly yield the necessary leakage areas. The test data obtained are analyzed in the framework of mathematical models to yield design leakage values. The leakage values shown in Table 6.2 apply for a pressure difference of 4 Pa, a somewhat arbitrary selection as discussed in Section 6.9.1. Thus, Equation 6.20 is an approximation, valid only for a certain range of pressures and flows; different n and K values may have to be used for other ranges. ASHRAE Fundamentals (2013) gives formulas to convert air leakage areas and airflow rates in residences determined under one reference pressure to other operating pressures.
Balancing Trade-offs between Deep Energy Retrofits and Heritage Conservation: A Methodology and Case Study
Published in International Journal of Architectural Heritage, 2022
Larissa Ide, Michael Gutland, Scott Bucking, Mario Santana Quintero
The temperature setpoint for heating was supposed to be 21°C, but because of the thermostat proximity to the entrance of the house, the house may be heating more often as if the setpoint were greater. This was accounted for in the calibration by increasing the temperature setpoint. The radiant hydronic heating system was modelled using a baseboard radiant convective water system. A baseboard radiator was assigned to each conditioned space. The radiators were connected to the gas boiler with a water outlet temperature of 82°C indicated by the boiler. The initial air infiltration was modelled using the calculated flow coefficients based on air changes per hour measured in a blower door test in 2017 which indicated 11 ACH at 50 Pa. The method used to calculate the air infiltration for the house in the energy model was the AIM-2 model by Walker and Wilson (1998) which is appropriate for smaller, residential buildings. The flow coefficient was calculated rearranging the equation in the AIM-2 model:
Application of passive measures for energy conservation in buildings – a review
Published in Advances in Building Energy Research, 2019
Farhad Amirifard, Seyed Amirhosain Sharif, Fuzhan Nasiri
For rating of airtightness in buildings, there are three methods of fan pressurization including blower door method (Jeong, Firrantello, Bahnfleth, Freihaut, & Musser, 2008; Kim et al., 2013) tracer gas method (ASTM, 2011) and simple acoustical method (Hassan, 2013). The fan pressurization including blower door method determines flow rate over the inner building envelope at different pressures, especially at 50 Pa pressure difference. When using this method, results are not impacted by climatic conditions (Finch, Straube, & Genge, 2009; Sfakianaki et al., 2008). However, the main drawback of this method emerges when building size increases and the air leakage of a high rise building needs to be measured. In that case, it is required to consider stack and wind effects and the large flow rate by many blower fans should be used to attain a pressure difference of at least 50 Pa (Bahnfleth, Yuill, & Lee, 1999). Some modified methods have been suggested efforts to tackle this problem including ‘The US Army Corps method’ (Zivov, Bailey, & Herron, 2009), The German ‘Fachverband Luftdichtheit im Bauwesen e.V.’ (Erhorn-Kluttig, Erhorn, & Lahmidi, 2009) method and the ‘guarded-zone method’ (Finch et al., 2009; Urquhart et al., 2015) All of these methods are based on the fan pressurization method with some modifications to make it applicable for high-rise buildings with varying numbers of units.
An indoor air quality evaluation in a residential retrofit project using spray polyurethane foam
Published in Journal of Occupational and Environmental Hygiene, 2018
Shen Tian, Scott Ecoff, John Sebroski, Jason Miller, Harold Rickenbacker, Melissa Bilec
Blower door tests were conducted using a Minneapolis Blower Door System (Model 3, The Energy Conservatory). One whole house blower door test was conducted before SPF was installed, and 3 blower door tests were conducted after SPF was installed. The goal was to evaluate the ACH for each floor. The blower door test measured 1 ACH50 (ACH at 50 pascals of negative pressure) which was then converted into ACHnatural (ACH at natural ventilation) by dividing an adjustment factor (N). N is a function of local climate, number of stories, sheltering and crack size of the house.[50,51] For the house studied, the factor N was calculated as 10.5, about half of the typical value (N = 20)[50] because this house was under major renovation and leakier than a typical residential building.