[en] The stack effect in a building is not a negligible factor on the air infiltration during winter season, especially where the substantial difference of temperature is observed. Even for one or two storey houses, the thermal effect in winter time is known to be sufficient enough to induce significant air-infiltration. It has been shown by both experiments and analysis that the stack effect equation derived from the ideal gas equation of state for the uniform outside and inside temperature of a building in accurate for the prediction of the pressure differentials induced by the stack effect provided that the value of the neutral pressure level (NPL) is known correctly. The study also demonstrated that the existing method recommended by ASHRAE, applicable only for a simple case of openings at top and bottom levels with uniform outside and inside temperature, for the value of NPL is inadequate. Reported herein are the results of an analytical and experimental study on the stack effect in a high-rise building where the internal temperature has a non-uniform distribution. (author)

[en] The determination of the air permeability of concrete in the compressed zone of NPP’s containment under conditions of excessive air pressure in the subshell space of the reactor compartment under a maximum design basis accident is necessary to confirm the localizing functions of the containment when extending the lifetime of power units. Approaches to determining the localizing ability (air permeability) of concrete in the compressed zone of the containment of NPPs with WWER-1000 type reactors under the impact of excessive air pressure under conditions of maximum design basis accident are discussed in the article. The designed testing installation for experimental studies of the air permeability of concrete by the method of stationary radial filtration is described and the results of experimental researches of the air permeability on the installation are presented for samples simulating the composition of concrete used under construction of the containment for Power Units No. 1, 2 (series B-302 and B-338, respectively) SD “South-Ukrainian NPP”. A comparative analysis of the results of above mentioned experimental researches with the results of experimental and theoretical work on the study of air permeability of the similar samples-imitators of concrete by the method of stationary linear filtration, as well as the results of measurements for samples of concrete sampled directly from the compressed zone of containment for Power Unit No. 2 of SD “South-Ukrainian NPP” was fulfilled. The results are explained by processes of compaction of the concrete structure under a complex stress state that occurs under specific hardening conditions and during long time compression by pre-stressed reinforcing ropes, which takes place under conditions of real containment operation. It was concluded that the simulators made according to the currently accepted technology cannot provide a correct determination of the localizing ability of the NPP’s containment, since the conditions and time of containment concrete hardening, as well as the long time constant compressive action of reinforcing ropes, cannot be correctly modeled in full under the formation of samples-imitators. The issue of the containment concrete samples imitators creating in laboratory conditions requires additional study, improvement of technology and the development of new approaches with maximum physical modeling of the conditions characteristic of the operation of the NPP containment (author)

[en] The model relates radon concentration to source strength and its variations, air exchange rate and meteorological factors. Two types of sources have been studied. The pressure difference dependent source is made up of radon transported with soil pore air and driven by pressure difference due to the stack effect. The constant source is made up of radon transported by diffusion from building materials or from soil. The air exchange rate depends exponentially on indoor-outdoor temperature difference and linearly on wind speed. These two inputs have been summed in quadrature. In a house with a constant source radon concentration decreases when the air exchange rate increases due to the increasing temperature difference, whereas the pressure difference dependent source causes an increasing concentration. This is due to the fact that the effect of the source strength increase is stronger than the decreasing effect of air exchange on concentration. The winter-summer concentration ratio depends on the combination of the two types of source. A pure pressure dependent source leads to the winter-summer ratio of 2-3.5 (winter -5 deg C, summer +15 deg C, wind speed 3 m/s). A strong contribution of a constant source is needed to cause a summer concentration higher than the winter concentration. The model is in agreement with the winter-summer concentration ratios measured. This ratio increases with the increasing winter concentration. The measured ratio was near 1.0 for houses with winter concentration of 200 Bq m''3 or less and near 2.0 with concentration of 1000 Bq m''3. In a house with a constant source, the diurnal maximum occurs in the afternoon, while in houses with a pressure difference dependent source the time of maximum is early in the morning

[en] The objective of this research is to quantify the effect of varying levels of induced duct leakage on differential pressures and subsequent radon levels in a typical Florida residence. The heating and air conditioning (HAC) system of a residence was modified with the addition of a fresh air ventilation system. This modification provided the ability to simulate either a return leak or a supply leak in the HAC system. The amount of leakage induced can be varied using flow control dampers and an auxiliary fan located in the ventilation system ductwork. The house was pressurized and depressurized by adding 0.06 m³/s of ventilation air into the return side and removing 0.05 m³/s of ventilation air from the supply side of the air handling system, respectively. The subsequent changes in house pressure and ventilation rates reduced the indoor radon concentrations from 1,865 Bq/m³ to 170 Bq/m³ under pressurized conditions and to 305 Bq/m³ under depressurized conditions

[en] Radon levels, ventilation rate and pressure differences were monitored continuously in four apartment houses with different ventilation systems. Two of them were ventilated by mechanical exhaust, one by mechanical supply and exhaust, and one by natural ventilation. The two-storey houses were constructed from concrete elements on a slab and located on a gravel esker. It was surprising to find that increasing the ventilation rate increased levels of radon in the apartments. Increased ventilation caused increased outdoor-indoor pressure difference, which in turn increased the entry rate of radon and counteracted the diluting effect of ventilation. The increase was significant when the outdoor-indoor pressure difference exceeded 5 Pa. Especially in the houses with mechanical exhaust ventilation the pressure difference was the most important factor of radon entry rate, and contributed up to several hundred Bq m^-3h^-1. (Author)

[en] The technique providing the use of the clothes' model is proposed for the investigation of the principles of the interchange of air between the space under protective coating and environment. The model completely fitting the clothing design and its air permeability was made of filtering material practically impermeable for aerosols. In this case for those exposed to radioactive aerosols the contamination of the space under protective clothing measured with a radiometre, can be attributed only to the air penetrating the design looseness of the clothes

[en] With the global environmental pollution and the lack of material resources, people are aware of the importance of ecological problems, and people begin to look at sports from an ecological perspective. Martial arts is a traditional sport of the Chinese nation. It has a long history and has evolved into today’s competitive martial arts after many years. The development status of Emishi martial arts is relatively slow compared to other provinces in China. This article will investigate and study the training venues of Emishi martial arts training institutions and the degree of support for martial arts projects by relevant government departments in various regions and cities. The environmental protection values of most training institutions do not meet the standards. There are few areas with standard competition venues. Local governments lack attention to martial arts and the reward system is not perfect. The study found that the application of Emishi martial arts aerobics in martial arts research camps from the perspective of ecological sports should be reflected in venues, props and costumes, music, teaching methods and non-intellectual factors. Choose a martial arts research camp with better air for the venue, environmental protection of props and clothing, music soothing to reduce noise, teaching methods and non-intellectual factors should follow the law of student development. (paper)

[en] Natural basement ventilation has always been recommended as a means of reducing radon levels in houses. However, its efficacy has never been documented. In these experiments, natural ventilation has for the first time been studied systematically in two research houses during both the summer cooling season and the winter heating season. Ventilation rates, environmental and house operating parameters, as well as radon levels, have been monitored. It can be definitely concluded from radon entry rate calculations that natural ventilation can reduce radon levels in two ways. The first is by simple dilution. The second is by reducing basement depressurization and thus the amount of radon-contaminated soil gas drawn into the structure. Therefore, basement ventilation can be an effective mitigation strategy under some circumstances. It might be especially useful in houses with low radon concentrations (of the order of 370 Bq m^-1) or those with low levels and which cannot be mitigated cost-effectively with conventional technology. (Author)

[en] Increasing the amount of exterior air coming into a building, combined with a natural gas heating source has proven to be profitable. A study in a residence for handicapped people showed that doubling the amount of exterior air coming into the building actually improved the comfort level for the occupants while reducing the total electric energy bill by 21 per cent

[en] Air exchange rates for residences and office buildings under sheltering conditions, only, that is, with doors and windows closed and fans off, are selected from the literature and correlated with wind speed and indoor-outdoor temperature difference. These exchange rates are found to be substantially less than those used previously in calculating the protection offered by sheltering. Graphed values of the ratio of interior:outside, time-integrated concentrations (the Dose Reduction Factor, DRF) are presented as a function of time. These apply to both gases and particulates. Especially for plumes of short duration, the resultant DRF's make sheltering a highly competitive protective action against the inhalation pathway. The inhalation DRFs are not the most favorable for depositing materials. Example DRF's are calculated and graphed for 2 μm aerodynamic diameter particles, as representing respirable plutonium (Pu). (Author)