Ventilation systems are known to influence radon concentrations indoors considerably. However, the initial results of the largest radon survey in 3660 Norwegian kindergartens conducted during heating seasons from 1996 to 1998 showed marginal effect of such systems. Clarification of this surprising result required a more detailed secondary investigation in a smaller group of kindergartens with balanced ventilation systems operating under special ventilation regime.
The wind speed and wind direction affected concentration of indoor radon in seven houses, which arelocated in three region of southern Finland. In the case of houses (B - F) which are built on upperslope of a permeable esker, according to the analysis of covariance the highest concentration of indoorradon, 20 - 33% over grand mean, was observed when wind (v?0.4 m.s-1) direction was perpendicularthe esker, leading to increasing pressure of soil gas and consequently to increased radon entry andconcentration.
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.
Within the Belgian Radon Programme the Belgian Building Research Institute is responsible for theinvestigation of techniques for prevention and mitigation of radon problems in dwellings. One of themost regular actions is the installation of a sub-slab depressurisation (SSD) system. As there are noready-to-use systems available on the Belgian market, a system has to be designed for every specificsituation.
A thermally conductive building envelope must be constructed to be permanently airtight - this has been compulsory according to German building regulations since 1 Jan. 1995. That 6 Para. 1 of the current Energy Saving Regulations, in force since 1 Oct. 2007, nevertheless requires construction of a airtight building envelope...
The Blower Door procedure has shown itself to be a very effective instrument for analysing and quantifying the various components of the total problem for complex ventilation issues...
Conventional techniques for the measurement of adventitious leakage of building envelopes are based on steady pressurisation at high pressures (e.g. 50 Pa) that are not normally encountered with natural or mechanical ventilation. It is the leakage at low pressures (e.g. 4 Pa) that is of interest and it is shown that...
For preselected totals of dwelling houses this article describes how statistical procedures on basis of small samples can be transferred into the prognosis whether the tolerable upper limit of airtighness is fulfilled or not. Necessary requirements on both sides are discussed - quality assurance during production of dwelling houses...
Thermography is often used to locate leaks in connection with an airtightness check. In this context it is important to know under what conditions the inspection system can recognise defects to a degree of certainty and reproducibility. Applications of leak location in checking airtightness use the excitation of the building envelope...
Implementing the EU-directive 2002/91/EF in Danish legislation led to regulations in the Danish Building Regulations on air tightness in buildings set out by the Danish Enterprise and Construction Authority, a department of the Danish Ministry of Economics and Business Affairs. From 2006 air leakage through the building envelope...
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