airtightness

Origins of toxic gas clouds may be diverse, including accidental releases due to industry or to hazardous materials transportation, or biological or chemical attacks. A protection to such a phenomenon consists in taking advantage of the protection offered by buildings against airborne pollutants. In this event, people can shelter in a building and wait until the toxic plume has gone.

In 1998, Persily published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the myth of the airtight commercial building. Since that time, the U.S. National Institute of Standards and Technology (NIST) has maintained a database of measured airtightness levels of U.S. commercial building leakages, in part to support the development and technical evaluation of airtightness requirements for national and state codes, standards and programs.

In France, starting on January 1st, 2013, a minimum airtightness value for all residential building will be required by the energy performance regulation (RT 2012). It will be compulsory to justify for any new residential building that its airtightness is below 0.6m3/h.m² at 4 Pa (Q4Pa_surf) for single-family houses and 1 m3/h.m² for multi-family buildings. 

The thrust of airtightness specification and testing is derived from energy considerations. The application to healthcare buildings and specialist laboratory facilities embodies the same principles but derives the appropriateness of the criteria with reference to [a] producing controlled and controllable cascading pressure zones and [b] specifying or quantifying the potential exposure in the event of failure of mechanical ventilation.

The feasibility of good air-tightness in new buildings can be determined based on the obtained air tightness classes as defined in EN 12237. In this paper a model is described which allows to calculate the energy loss caused by leak losses in ventilation systems based on the air tightness class and the feasibility of realising a good air-tightness.

Air leakage test was carried out according to ASTM E779-03, Standard Test Method for Determining Air Leakage Rate by Fan Pressurization to meet the requirements of the LEED-NC v2.2(EQp2). Air leakage tests for quality assurance can be performed once all work on the air barrier has been completed and all windows and doors have been installed in two high-rise residential buildings. Test units selection was carried out in accordance with the following guidance, California’s 2001 Energy Efficiency Standards.

This report summarizes the state of the art on building air tightness by reviewing the current and recent literature on both research and practice. The focus of this report is on techniques to measure the tightness of the building envelope and on what has been learned by doing so. This report reviews over 100 of the most important publications relating to the topic. The report covered the fundamentals of air leakage including the hydrodynamics of leaks, which has led to all of the measurement techniques currently in use.

In 1995 and 1996 radon concentrations and effective air flows were measured in about 1500 Dutchdwellings built between 1985 and 1993. The goal of this investigation was to describe the trend inthe average radon concentration by supplementing the first survey on dwellings built up to 1984and to quantify the contributions of the most important sources of radon. In the living room of newdwellings the average radon concentration was 28 Bq m-3, which is 50% higher than in dwellingsbuilt before 1970.

The traditional house of Japan, Kominka, is constructed of wooden pillars and beams, and clay walls.The indoor space in the Kominka remains cool in summer because overhanging eaves block solarradiation and the open frame airs out. Technology to make small cracks airtight is undeveloped.Consequently, drafts enter the indoor space and chill occupants during winter. Improvements of indoorclimate have not been realized. This report describes "Yukis house," which is a Kominka built in thelatter 1700s, defined as a residence of the privileged class.

International building legislation is setting stronger and stronger requirements for the energy performance of buildings. The most recent example is the Energy Performance of Buildings Directive in the European Union. The improved energy performance of buildings can't be achieved by additional insulation or more effective building systems only. A major influence factor on the energy quality is the ventilation technology and also the airtightness of the building.