air tightness

Studies on buildings’ airtightness have shown that several issues can arise from uncontrolled airflow leakages in buildings (e.g., higher energy cost, thermal comfort and health of occupants, building components and equipment preservation). Indeed, the ne

This paper presents an approach to evaluate the sensitivity of a roof design to condensation problems, given the uncertainty to achieve continuity of airtightness in practice. The approach consists of a repeated number of simulations with a 2D heat, air and vapour transfer model to predict the variation in roof moisture performance due to various discontinuities in roof geometry. The set of discontinuities is calibrated by comparing measuring data of roof airtightness to simulation results.

Air infiltration through the exterior envelope of a residential building impacts significantly on the heating energy consumption and cost, especially in a cold climate such as Montreal's. Therefore to renovate existing houses to the level of new well-built houses in terms of airtightness will lead to a reduction of the heating energy costs. By considering the life-cycle energy consumption and the initial cost of renovation, and the CO2 tax credits, the paper estimates the cost-effectiveness of this type of renovation.

States that 80% or more of infiltration is due to the many imperfections designed into the building envelopes. Discusses the problem and the role of ANSI/ASHRAE Standard 62-1999.

Attempts to determine the influence of the installation of highly insulated windows and central heating systems on indoor climate, and mite-allergen (Der f 1) and mould spore concentrations. A before and after study was carried out on 98 apartment bedrooms, with measurements taken of air exchange rate, temperature and humidity. A lifestyle and housing conditions questionnaire was undertaken by the occupants and dust on carpets and mattresses was analysed for mould spores and Der f 1.

Outlines a 'healthy house' design for suburban Australia. The design incorporated a tight building envelope and a ducted mechanical ventilation (and heat recovery) system, providing a minimum ventilation rate of 0.35 air changes per hour. Partial filtration and dehumidification of the air was also included. Low-VOC building materials were chosen. Total volatile organic compound (TVOC) concentrations were approximately 4,000 microgrammes per m3 just after construction, decreasing by a double-exponential model to 300 microgrammes per m3 by eight months, which is good.

States that with the ill effects of poor indoor air quality often in the news these days, it pays to design and build a house that is healthy from the start. States that a comprehensive approach to residential design has emerged in recent years that makes both energy conservation and good indoor air quality achievable in homes.

The airtightness performances of buildings and ventilation systems can have a major impact on the indoor climate (IAQ, thermal comfort,...) and on the energy performance. Measurement results for Belgian buildings clearly show that the airtightness is often moderate to very poor. As part of the proposed energy performance legislation for the Flemish Region, it is envisaged to pay attention to the airtightness of buildings and ductwork. In the first part of the paper, results found for Belgian buildings and systems are briefly presented and discussed.

Ventilation plays an important role in the RT 2000 regulation. The ventilation system is of course taken into account, but also the building envelope airtigthness on which this paper focuses.

The NEN 5128 "Energy performance of dwellings and residential buildings- Determination method" [1] describes a procedure to calculate the energy performance coefficient EPC. The requirements are given in the Dutch Building Decree [2]. The energy performance is expressed as an Energy Performance Characteristic (EPC). In this EPC procedure ventilation and air tightness play an important role. This paper describes the role of ventilation and air tightness in the Energy Performance Standard. Moreover it gives the alternative way of the so called equivalence principle.