The Leakage Rate Index (LRI) is a numerical value used in airtightness testing to quantify the level of air leakage within a building’s envelope. It serves as a crucial parameter in assessing the airtightness performance of a structure. The LRI provides a standardized measure of the air leakage rate per unit of building envelope area, expressed in units such as cubic meters per hour per square meter (m³/h·m²) or cubic feet per minute per square foot (CFM/ft²).
By measuring and calculating the LRI, building professionals can evaluate the efficiency of the building’s envelope in containing conditioned air. A lower LRI value indicates a higher level of airtightness, suggesting that the building envelope has minimal air leakage points. This is desirable as it helps improve energy efficiency by minimizing the loss of conditioned air and reducing the need for excessive heating or cooling.
The LRI is commonly used in airtightness standards and regulations to set performance targets and assess compliance. It enables accurate comparisons between different buildings or components, allowing for benchmarking and identification of areas that require improvement. By addressing areas of excessive air leakage indicated by the LRI, building owners and professionals can implement effective strategies to enhance the building’s airtightness, leading to improved energy efficiency, thermal comfort, and indoor air quality.