TN

Due to the rapid urbanization and modernization of Korea, the demand for housing has increased considerably more than in other countries. As a result, the apartment building has become the prevalent housing type in many cities and suburbs in Korea. Today, the demand for an improvement in the qualitative aspects of housing is growing considerably due to the increase in the housing supply rate.

The Czech Republic is a landlocked country located in the centre of Europe. The area of the Czech Republic is 78,866 km² and its population is about 10.4 million people. The Czech Republic was part of the former Czechoslovakia until 1993 and it has been a member state of the European Union since May 2004. The Czech Republic is an industrialized country enjoying a decent gross domestic product (GDP) growth (6.6 percent in 2007). The GDP per capita is currently at about 82 percent of the average of the 27 EU member states.

Low income households in developed and less developed countries suffer from serious indoor environmental problems like heat stress, lack of comfort and poor indoor air quality. This has a very serious impact on the quality of life and health of poor citizens. More than 2 million deaths per year are attributable to indoor air pollution from inadequate use of fuels, while thousands of low income citizens die because of high indoor temperatures.

Because of specific urban characteristics, the potential of natural ventilation can be seriously decreased in the urban environment because of reduced wind speeds, high ambient temperatures and increased external pollutant and noise levels. Besides, the performance of hybrid ventilation systems is also affected and they are expected to work most of the times with mechanical ventilation.

Ventilation standards and guidelines typically treat ventilation as a constant and specify its value. In many circumstances a designer wishes to use intermittent ventilation, rather than constant ventilation, but there are no easy equivalencies available. This report develops a model of efficacy that allows one to calculate how much intermittent ventilation one needs to get the same indoor air quality as a the continuous value specified.

This AIVC Technical Note has been produced in the frame of the EU RESHYVENT project, conducted from January 2002 to December 2004. An outline of this project is given in the introduction of this report. The report initially was aimed at the project participants; however, many information may also be of general interest to manufacturers and designers of hybrid residential ventilation systems. Therefore it has been made available to a wider audience by publication as an AIVC TN.

The basic strategy for providing indoor air quality in residences is to dilute indoor sources with outdoor air. This strategy assumes that the outdoor air does not have pollutants at harmful levels or that the outdoor air is, at least, less polluted than the indoor air. When this is not the case, different strategies need to be employed to ensure adequate air quality in the indoor environment. These strategies include ventilation systems, filtration and other measures.

Ventilation is required to provide to remove or dilute pollutants and incidentally meets metabolic oxygen requirements for occupants. In addition ventilation may also be required to provide oxygen for combustion devices and as a means of summer cooling.

Ductwork is used for transport of air used for ventilation or air conditioning in buildings. The supply air is typically conditioned (filtered, warmed or cooled, sometimes humidified or dehumidified). It is important that the air is distributed properly in the building. Thus the duct system must be well balanced regarding airflow rates, or have provisions controlling the air distribution. The ducts should have a low leak rate. A primary function is also thermal insulation to protect the heat content of the air.

This review attempts to summarise available airtightness, minimum ventilation rate and indoor air quality requirements, standards, codes of practice and regulations. It also attempts to determine the nature and type of thermal insulation requirements and the rationale behind the data outlined in this report. Attempts have also been made to normalise the data, where appropriate to enable comparisons to be undertaken.