[en] Airtightness at building component scale deserves much more focus than it gets. Unfortunately, the most popular method (i.e., indirect method) for its in-situ measurement suffers from substantial uncertainties. An alternative method is the direct component testing: a pressure chamber isolates the component from the rest of the building. This paper presents the method performed on three different newly-installed windows. These applications highlight three difficulties encountered: the chamber must resist to pressure differences higher than 50 Pa, the duct linking the fan to the chamber should be straight and the measured leakage should be perfectly identified. Then, authors performed two series of tests (10 and 12) in repeatability conditions. These allow to compare the uncertainty of the direct component testing (0.29 m³/h, 9.7%) with the expected uncertainty of the indirect method for a similar case (1.53 m³/h, 51.2%). These findings indicate a strong potential for the direct component testing to be used for in-situ measurements. Further work should tackle three limitations of this study identified by authors: other building component should be tested; other repeatability tests should be performed to identify factors responsible for the results variation; and both methods (i.e., direct and indirect) should be compared on the same case. (paper)

[en] The state of the art is presented for testing procedures for tightness inspections of WWER-440 type reactor hermetic spaces, using measurements of the time dependence of pressure. A new evaluation method is described providing an unambiguous value of leak rate even if this value is extrapolated from low level overpressure measurements to maximum accident overpressure. If the leak test initial overpressure is different in two measurements for one hermetic space, the extrapolated leak rates have equal values. Application of this method allows NPP operators to find physically well-founded results for hermetic spaces tightness quality evaluation which can be used for time reviews of tightness development and also as basic data for nuclear power plant safety calculations. (J.B.) 11 figs., 3 refs

[en] The Energy Performance Certificate (EPC) allows building users to be informed and aware of the quality of the buildings in terms of energy needs. Additionally, the EPC includes a future for existing buildings, which is the incorporation of a Recommendation list of Measures (RLMs) to improve their energy performance in a cost-effective way. Which have risen the question if this tool can provide trustful Cost-effective recommendations due despite the uses of standardized inputs. This study focuses on estimating the impact of using measure ventilation rate, heating set point and airtightness on the profitability of the recommendations. The study is based on common dwelling in Norway, comparing results obtained with a Building Performance Simulation Software, following the Norwegian standard for energy certification and with the uses of measured ventilation rate, airtightness and real heating set points. The results show that the performance gap can be reduced significantly just by adopting these inputs, increasing the confidence on the RLMs and reducing the uncertainty of the investment. (paper)

[en] When the temperature in the airtight radon chamber was adjusted, it would induce the frequent changes of the air pressure in chamber, then the radon concentration in the radon chamber would continuously reduce, which could seriously destroy the stability of the radon concentration in radon chamber. In this paper, on the study of the effect reasons to the stability of radon concentration in airtight radon chamber due to the thermoregulation, a new amendment scheme was put forward, and the solutions of the relevant parameters were discussed. The amendment scheme had been successfully applied to HD-6 radon chamber, and achieved good results. (authors)

[en] More than one million and a half houses have too important levels of radon. This gas is a carcinogen gas but it is easy to get rid of it. This article reviews the different possible techniques. (N.C.)

[en] The hot summer and cold winter zone in China belong to the non-central heating area. In recent years, with the improvement of people’s living standards, more and more residential building have begun to adopt various heating methods. However, many existing buildings have poor air tightness level, and the indoor thermal environment is in a bad condition, which also causes a great waste of energy. Based on the actual measurement of the airtightness of a demonstration building, this paper studies the effects of residential airtightness on heating and air conditioning energy consumption and indoor thermal environment in winter. The simulation results show that in the hot summer and cold winter zone, the level of air tightness also influence the heating and air conditioning energy consumption, but the impact on heating energy consumption is more obvious. In addition, when selecting energy-saving measures, the relationship between the level of air tightness and the level of insulation should be weighed. We should not reduce energy consumption only by improving the airtightness level. Otherwise, the investment is large and the energy saving effect is very poor. (paper)

[en] Indoor radon concentrations were estimated for various ventilation conditions, the differences being mainly related to the airtightness of the dwelling and the ventilation behavior of its occupants. The estimations were aimed at describing the variation in air change rates and radon concentrations to be expected in the representative newly built Dutch dwellings and identifying the most important parameters determining air change rate and indoor radon concentration. The model estimations were compared with measurements. Most of the air was predicted to enter the model dwelling through leaks in the building shell, independent of the ventilation conditions of the dwelling. Opening the air inlets was shown to be an efficient way to increase infiltration and thus to decrease radon concentration. The effect of increasing the mechanical ventilation rate was considerably less than opening the air inlets. The mechanical ventilation sets the lower limit to the air change rate of the dwelling, and is effective in reducing the radon concentration when natural infiltration is low. Opening inside doors proved to be effective in preventing peak concentrations in poorly ventilated rooms. As the airtightness of newly built dwellings is still being improved, higher radon concentrations are to be expected in the near future and the effect of occupant behavior on indoor radon concentrations is likely to increase. According to the model estimations soil-borne radon played a moderate role, which is in line with measurements. (au)

[en] Subject of a research project carried out at Material Testing Institute (MPA) University of Stuttgart was the investigation of bolted flange connections (DN100 PN100 and PN160) of metal-to-metal contact type. In a special test rig external loadings (axial forces, bending and torsional moments as well as shearing forces) can be applied in addition to the internal pressure. Further on an analytical approach was developed for the determination of the loading in different cross sections of the flanges and for the tightness proof by means of the gap between the flanges at the position of the gasket. On the basis of a comparison of the experimental results and those of numerical calculations with results according to the new developed analytical approach the latter can be regarded as validated as far as investigated. In the nuclear code KTA 3211.2 (draft 2003) [1] the flange rotation at metal-to-metal contact (MMC) is restricted globally to 0.1 . This limitation does not comply with a lot of bolted flange connections in service although the strength and tightness criteria are met. This problem is now resolved with the new developed analytical approach which takes also into consideration the non-negligible influence of the assembly bolt load exceeding the minimum required bolt load for metal-to-metal contact. In a following project for defined boundary conditions the basis for the strength and tightness proof for bolted flange connections (MMC type) without explicit calculation shall be created. (orig.)

[en] Radon measurements in some buildings in the town of Jachymov indicated that the limiting volume activities were exceeded substantially. Remedial actions were made in the nursery school building. These included gravitational ventilation of the cellar, fitting of all doors and passages between the cellar and school rooms with packing, installation of overpressure ventilation with heat recuperation, and sealing of all window gaps. (J.B.). 2 refs

[en] Radon concentrations and external exposure by nuclides of the U-238 decay chain were quantified for a typical Dutch townhouse using a series of interconnected computer models. The effect is studied of changes in parameter values which have simulated changes in building practices over the past decades. Three groups of parameters were distinguished: (1) the air-tightness of the building shell and the distribution of leaks over outer walls and ground floor, (2) the radon-relevant characteristics of the building materials, and 3) those characterising 'habits of the occupant', such as changing mechanical ventilation rate and opening of air inlets or doors. The relative importance of increased air-tightness and of substitution of concrete by other building materials in new dwellings is illustrated. On average changes in building practices clearly enhanced the radon concentration in the living room without affecting external exposure. In new, airtight dwellings the relative effect of occupant behaviour is demonstrated as considerably larger than in old ones