English

There is increasing evidence that indoor environmental conditions substantially influence health and performance. Macro-economic estimates show that the potential benefits from indoor environmental improvements for the society are high. Some calculations show that the estimated cost of poor indoor environment is higher than energy costs of heating and ventilation of the same buildings.

This paper gives an overview of a few quality assessment methods used for ventilation systems. They cover two categories of approaches: regulatory compliance checks, that are external to the building project actors; voluntary contract-based quality assessment procedures, e.g., embedded in a certification scheme. The examples are briefly described and analysed. Quantitative results are given where possible.

The ventilation of an attic is critical in estimating heating and cooling loads for buildings because the air temperature in the attic is highly sensitive to ventilation rate. In addition, attic ventilation is an important parameter for determining moisture accumulation in attic spaces that can lead to structural damage and reduced insulation effectiveness. Historically, attic venting has been a common method for controlling attic temperature and moisture, but there have been no calculation techniques available to determine attic ventilation rates.

Field tests were carried out in two flat ceiling, residential attics at a dedicated test site over a two year period. The scope of this paper is to present measurements of ventilation rates, indoor-attic exchange rates, temperatures and wood moisture contents at various locations in the attics. Attic ventilation rates are correlated with wind speed, wind direction, and attic-outdoor temperature difference. Wind speed is shown to be the dominant driving force for ventilation; however, wind direction is important particularly when the attic is sheltered.

The paper is devoted to the trial implementation of two different types of hybrid ventilation systems in dwelling buildings done in the scope of the EU LIFE Programme supported project ECOVENT.Recent changes in Latvian Building Codes require higher thermal resistance of buildingstructures, air tight windows and mandatory ventilation systems. Use of mechanical ventilationsystems may reduce the positive effect of improvements of thermal performance of buildingstructures by 30-40% of the achieved economy.

The objective of the project was to design an HVAC system for a lithium battery manufacturing facility in Minnesota, USA. The system was to be designed for a 7544 sq. ft. space with a 9 ft high ceiling, to be maintained at 25 F dew point temperature (1.3% relative humidity @ 70 F dry bulb temperature). The facility had to be designed and constructed inside an existing warehouse style, 14 ft high roof building, absolutely vapor tight, such that no moisture can migrate to the indoors from any interior walls, floor or roof.

Forced air distribution systems in residential buildings are often located outside conditioned space, for example in attics, crawlspaces, garages and basements. Leaks from the ducts to these unconditioned spaces or outside can change flows through the registers and change the ventilation rates of the conditioned spaces. In this study, duct leakage flows were measured in several low-rise apartment buildings. The leakage flow measurements and other data about the apartments were used to develop a prototype apartment building.

ASHRAE has recently published its first residential ventilation standard, Standard 62.2-2003. This standard defines the roles of and minimum requirements for mechanical and natural ventilation systems and the building envelope intended to provide acceptable indoor air quality in low-rise residential buildings. The standard includes a minimum whole-house ventilation rate, local exhaust rates and other kinds of source control. This report summarizes the standard and indicates the key issues.

Infiltration has traditionally been assumed to contribute to the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Some studies have indicated that application of such a simple formula may produce an unreasonably high contribution because of heat recovery within the building envelope. The major objective of this study was to provide an improved prediction of the energy load due to infiltration by introducing a correction factor that multiplies the expression for the conventional load.

Indoor Air Quality represents a very ambitious challenge in developed countries. As already shown in previous studies, four phenomena are influencing the air pollution level indoors. These are ventilation indoor emissions, chemical reactions in the bulk air-phase of the rooms, and physico-chemical interactions between pollutants and building materials.