Michal Kraus

Risk Assessment of Airtightness of Building Envelope

The paper deals with risk analysis of insufficient airtightness of the envelope construction. The risk analysis is a systematic and structured data processing to identify potential hazards. The main aim of paper is to qualified risks which arise from the danger, i.e. insufficiently airtight of the building envelope. The quality of airtight building envelope except for low energy consumption also minimizes the risk of damage to the structure associated with the spread of the heat, water vapor in the structure and fungal growth. The qualification of risks consists of choice of method and determinative indicators, input data and simulation of model with drawing results.

The importance of quality of realization on airtightness ofbuilding envelope

The paper analyzes the significance of quality of execution and ongoing controls affecting the final airtightness of building envelope. The realization of building with well airtight building envelope must be more consistent and rigorous than the realization of conventional building. There are two ways to realization of energy - efficient buildings. On the one hand, there is a realization using a professional construction companies. On the other hand, it is a realization of the building themselves (self-build). The aim of the paper is to verify the statistical dependence of the final airtightness building envelope between the realizations using by professional construction companies and self-build.

Indoor Environment in Residential Prefabricated Buildings

The contribution presents results of the experimental measurement of indoor air quality in residential prefabricated buildings. People spend about 90% of their life in the indoor environment of buildings. Hygrothermal parameters and indoor air quality are the essential component that define the quality of the indoor environment. The results of case study characterize the quality of the indoor environment of the ordinary occupants in housing unit of residential prefabricated building. A current problem of revitalized prefabricated buildings is inadequate air exchange and related thereto to poor indoor air quality. The experimental measurements were carried out just before and at the beginning of the heating season (from 1st October to 30th November 2016). Heating season was launched in the middle of experimental measurement. The wireless indoor sensor Elgato Eve Room was used for measurements. The obtained values of indoor air temperature [C], relative humidity [%] and indoor air quality [ppm] are describe and analysis in this study. The results of the study indicate that the values of temperature and indoor air quality meet optimal levels during the experiment with nuances. The mean air temperature in the indoor environment is 22.43 C. The temperature of the indoor environment is held at the optimum level (18-24 C) for 94.50% time of the experimental measurements. In addition, the indoor air quality in the context of the content of harmful volatile organic compounds (VOCs) has been excellent for almost 91% time of the total experiment. However, the values of relative humidity were less than the optimum value nearly 40% of the total observed time. The mean 10-minutes values of relative humidity during the heating season is about 10% lower than the mean 10-minutes relative humidity before the heating season.

Hygrothermal Analysis of Indoor Environment of Residential Prefabricated Buildings

Recent studies show that the relative humidity and the indoor air temperature constitute an important determinant of the quality of indoor air. Hygrothermal microclimate has a significant impact on occupants health and their comfort. The study presents the results of experimental measurement of indoor air temperature and relative humidity in selected apartment in prefabricated panel house situated in Ostrava, Czechia. The contribution describes and analysis the relation between indoor air temperature [°C] and relative humidity [%] in this apartment. The experimental object is selected with respect to the housing stock in the Czech Republic. A third of the housing stock in the Czech Republic is composed of prefabricated panel houses. Regeneration and revitalization of these buildings were in the focus of interest during recent years. Building modifications, such as thermal insulation of building envelope or window replacement, lead to a significantly higher level of airtightness of these objects. Humidity and indoor air temperature are measured in 10-minute cycles for two periods. The values of temperature and humidity are measured for the non-heating and the heating season. The length of each experimental period is 30 days. The mean value of indoor air temperature is 22.21 °C and average relative humidity is 45.87% in the non-heating period. The values of 22.62 °C and 35.20% represent average values for the heating period. A slight increase of the average temperature of the indoor environment (+1.85%) is observed. The decrease of the relative humidity is evident at first glance. The relative humidity of the internal environment is approximately 10% lower in the heating period. Long-term decline of relative humidity below 30% brings many problems. It is necessary to take measures to increase of relative humidity in residential prefabricated building. The aquarium appears to be ineffective. The solution may be forced artificial ventilation or humidifiers.

Indoor Noise Loading in Residential Prefabricated Buildings

Quality on indoor environment is among others also defined by an acoustic comfort and noise emissions. The indoor noise loading in the residential prefabricated buildings is specific problem related to structural design of these buildings. Problems with noise level of sanitary systems are mostly associated with hydraulic shock such as water distribution and sewage drainage. Another very common cause of excessive noise is also flushing the toilet or water fall on enamelled steel (bath or shower). This paper aims to analyse the acoustic properties in the residential prefabricated buildings. Sanitary core of the assessed apartment is in original condition without any alterations. The sanitary core is based on a formica (high-pressure laminate). The study discusses the maximum sound levels in the three assessed rooms for the three different noise sources. The values of maximum noise level are measured for the corridor, bedroom and living room. Sources of noise are common activities relating to the operation of sanitary core - the toilet flush in the toilet, falling water from the shower in the bathroom and the water falling on the bottom of the kitchen sink in the kitchen. Other sources of noise are eliminated or minimized during the experiment. The digital sound level meter Testo 815 is used for measurements. The measured values of maximum sound level LA,max [dB] are adjusted by the correction coefficient. The obtained values are compared with the hygienic limits for day and night period. Night hygienic limit (30 dB) is exceeded in all the rooms for all noise sources. This limit is exceeded from 17 to 73%. The values in the bedroom and the living room meet the daily hygienic limit (40 dB). The daily limit is exceeded only in the corridor. The highest values of noise are identified for the toilet flushing.

Contemporary State and Development of a Concept of Passive House

This paper deals with the development of requirements for the energy-passive construction. The main emphasis is focused on a new categorization of passive houses into classes according to the Passivhaus Institute: the Passive House Classic, the Passive House Plus and the Passive House Premium. The requirement for annual specific heating demand is unchanged, maximally 15 kWh/(m2·a). A new evaluation system of Energy Passive Houses is based on renewable primary energy (PER). The aim of the paper is a description and evaluation of various classes of energy passive houses, including feasibility analysis and model examples.

The Statistical Verification of Significance of Airtightness and Energy Performance

The main objective of the paper is to confirm or exclude a statistically significant impact of airtightness on the energy performance of buildings. Energy performance of buildings is characterized by a specific energy demand for heating and specific total primary energy. Airtightness is one of the key factors of energy efficient buildings. The quality of airtight building envelope except for low energy consumption also minimizes the risk of damage to the structure associated with the spread of the heat and water vapor in the structure.