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2025 Vol.19, Issue 5 Preview Page

Research Article

Derivation of Conversion Factor N for Evaluating Natural Air Infiltration Rates

기밀성능 데이터를 이용한 자연상태 침기량 산정을 위한 변환계수 N 도출

Su-Jin Lim1
,
Jae-Hun Jo2*
,
Ji-Hyoung Kim3
,
Ju-Hee Seo4
,
Ha-Kyung Shin4
,
Doo-Yeon Kim4
,
Hyeon-Chul Jeong4
임 수진1
,
조 재훈2*
,
김 지형3
,
서 주희4
,
신 하경4
,
김 두연4
,
정 현철4
1Master Course Student, Department of Architectural Engineering, Inha University, Incheon, Korea
2Professor, Division of Architecture, Inha University, Incheon, Korea
3Master Course Student, Department of Smart City Engineering, Inha University, Incheon, Korea
4Bachelor, Department of Architectural Engineering, Inha University, Incheon, Korea
1인하대학교 건축학부 건축공학전공 석사과정
2인하대학교 건축학부 교수
3인하대학교 스마트공학전공 석사과정
4인하대학교 건축학부 건축공학전공 학사
*Corresponding Author
30 October 2025. pp. 201-211
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Abstract

The evaluation of natural air infiltration rates in buildings commonly uses the ACH50 value divided by an N-factor, but the standard N-factor of 20, derived from foreign contexts, may not accurately reflect Korean conditions. This study seeks to propose a more suitable N-factor using a theoretical model that incorporates pressure differences arising from the stack effect, wind, and mechanical systems. Pressure differences were calculated by analyzing 25 years of wind speed and outdoor temperature data (2000–2024) and validated through statistical methods, including normality tests. Additionally, Blower Door Test results from over 1,400 residential buildings were analyzed, with outlier removal conducted during preprocessing. The representative pressure differences were applied to leakage functions to compute N-values, and probability density functions were used to calculate weighted representative values. Findings reveal significant variations based on building height and seasonal changes. High-rise buildings are especially impacted by the stack effect, while low-rise buildings show less variation. The highest N-factor was observed in summer, reflecting the smaller temperature difference between indoor and outdoor environments, which results in a lower estimated infiltration rate. Conversely, the larger temperature difference exceeding 10℃ during winter enhances stack-driven infiltration, leading to a lower N-factor.By deriving an N-factor tailored to Korea’s building environment, this study improves the accuracy of natural air infiltration rate calculations and enhances energy modeling efficiency.

Keywords
Natural Infiltration
Pressure difference
Conversion factor
Weather data
Airtightness
키워드
자연 침기량
압력차
변환계수
기상 데이터
기밀성능
References
1

Ji, K.H., Choi, S.J., Jo, J.H. (2023). Field Study on Impact of Mechanical Pressurization on Pressure Distribution in High-Rise Buildings. Buildings, 13(12), 3039.

10.3390/buildings13123039
2

Jo, J.H. (2010). Measurements of the Dwelling Unit Airtightness in High-rise Residential Buildings. Journal of the Architectural Institute of Korea, 26(10), 337-344.

3

Jo, J.H., Yeo, M.S., Kim, K.W. (2005). Pressure distribution due to Stack Effect in high-rise residential Buildings. Journal of the Architectural Institute of Korea, 21(5), 207-214.

4

Lozinsky, C.H., Touchie, M.F. (2023). Quantifying suite-level airtightness in newly constructed multi-unit residential buildings using guarded suite-level air leakage testing. Building and Environment, 236, 110273.

10.1016/j.buildenv.2023.110273
5

Mun, J.H., Lee, J.I., Kim, M.S. (2020). Study on Estimation of Infiltration Rate (ACH natural) using Blower Door Test Results. Journal of Korean Institute of Architectural Sustainable Environment and Building Systems, 14(6), 687-698.

6

Pang, S.K. (2012). Heat Transfer Characteristics and Temperature Decay Behavior of Building Shaft using CFD Simulation. Construction and Environment Research Institute, 7(2), 93-100.

7

Sadineni, S.B., Madala, S., Boehm, R.F. (2011). Passive building energy savings: A review of building envelope components. Renewable and Sustainable Energy Reviews, 15(8), 3617-3631.

10.1016/j.rser.2011.07.014
8

Emmerich, S.J., Persily, A.K., McDowell, T.P. (2005, September). Impact of infiltration on heating and cooling loads in US office buildings. In Proceedings of the 26th IEA Conference of the Air Infiltration and Ventilation Center. 21-23.

9

Kang, K.N., Lee, S.W., Lee, E.J., Park, M.J., Lim, J.H., Jo, B.R., Lee, J.C. (2015). Infiltration : Just ACH50 Divided by 20? - Concentrated on a Residential Building. Proceedings of the SAREK 2015 Summer Annual Conference, 435-438.

10

Henderson, H., Harley, B. (2022). Infiltration Guidance for Buildings at Design Conditions. New York. NYS Clean Heat Program.

11

U.S. Department of Energy. (2023). EnergyPlus™ Version 23.2.0 Documentation:　Engineering Reference. Chapter 8.3. Infiltration/Ventilation.

12

ASHRAE. (2017). ASHRAE Handbook-2017:Fundamentals. Chapter 24. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers.

13

Liddament, M.W. (1986). Air Infiltration Calculation Techniques-An Applications Guide, AIVC.

Information
  • Publisher :Korean Institute of Architectural Sustainable Environment and Building Systems
  • Publisher(Ko) :한국건축친환경설비학회
  • Journal Title :Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
  • Journal Title(Ko) :한국건축친환경설비학회논문집
  • Volume : 19
  • No :5
  • Pages :201-211
  • Received Date : 2025-08-19
  • Revised Date : 2025-09-05
  • Accepted Date : 2025-09-09
  • DOI :https://doi.org/10.22696/jkiaebs.20250018
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