AIVC - Air Infiltration and Ventilation Centre

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air tightness

A consequence analysis of new Norwegian building regulations on air infiltration.

In 1981 Norwegian building regulations introduced quantitative requirements to air leakages in different types of buildings. The requirements were formed as maximum allowed air changes per hour at 50 Pa pressure difference according to the pressurization method. To evaluate the consequences of these new requirementsimposed to Norwegian building industry a model proposed by the Nordic Committee for Building Regulations (NKB) was used. The average air leakages of residential buildings , built before the new requirements,are known through a research project performed i n 1979.

Airtightness standards for buildings - the Canadian experience and future plans.

The situation in Canada with regard to building regulations affecting the airtightness of buildings is reviewed with emphasis on a new standard test method for measuring airtightness which departs somewhat from methods used inother countries. The purpose of this test is held to be primarily to determine an important aspect of building envelope quality, namely the degree to which unintentional openings have been avoided, rather than to determine energy conservation potential.

Performance of passive ventilation systems in a two-storey house.

Air change rates were measured in one two-storey detached house with five basic types of passive ventilation systems: an intake vent in the basement wall, an outdoor air supply ducted to the existing forced air heating system, an exhaust stack extending from the basement to the roof, and two combinations of the supply systems and the exhaust stack. An expression was developed for estimating house air change rate from house airtightness, neutral pressure level and indoor-outdoor air temperature difference.

Energy performance standards regarding air infiltration of buildings in Switzerland.

The Swiss performance standard for energy conservation in buildings SIA 380/1 is explained. This standard leaves air infiltration and other detail decisions to planners if minimum performance levels are met. Calculation procedures for heat balances based on a standard occupancy are described. Tools to achieve optimum space heating and ventilation rates are explained. Instrumentation for checking the thermal performance of the house in operation is defined.

Review of building airtightness and ventilation standards.

Increased attention to the reduction of energy consumption in buildings and greater awareness of the need to maintain acceptable standards of indoor air quality have led to the development of new or revised standards of building airtightness and ventilation requirements. In this review of the existing standards of twelve countries, an attempt has been made to compare their main features and criteria. In many cases, direct comparison is not possible because of different ways of expressing the significant parameters.

Description of ASHRAE's proposed air tightness standard.

ASHRAE is preparing a standard which addresses the maximum air leakage associated with good construction. This standard, 119P, links Standard 90, which addresses energy conservation in new residential construction, and Standard 62, which specifies the minimum acceptable ventilation to achieve adequate indoor air quality. Within Standard 119P there is currently a classification scheme that groups building tightness into categories depending on envelope leakage, floor area and building height.

Constancy of air tightness in buildings.

The air tightness of 15 detached houses was measured firstly immediately after erection and secondly after a period of 1.5 to 4.5 years. All the houses were timber framed ones, equipped with mechanical ventilation systems. Only two houses out of the 15 tested showed clear changes in air tightness. Thus the air tightness behaviour of the houses seems to be fairly constant.

Better airtightness: better or worse ventilation?

In Finland there are not yet any regulations or standards concerning the airtightness of buildings. Drafts have caused discussion about whether controlled airtightness would increase the building costs too much, and improved airtightness worsen the indoor air quality. In modern Finnish buildings a good or satisfactory airtightness can be achieved with normal careful workmanship. To secure good indoor air quality, a functioning ventilation system is also necessary. There seems to be no return to traditional 'breathing' structures and natural ventilation.

Comfortable conditions - a target for climatic research workers.

Describes the work of the Department of Climate and Building Services of the National Swedish Institute for Building Research. Full scale trials, field measurement and measurement technology and methods applied to indoor climate are described. Research on airtight buildings, radon, air quality and efficient ventilation, occupant requirements and effects on human performance is also summarised. Dummies are used to measure heat transport to or from parts of the body, and for measurement of humidity.

Humidity problems in buildings Problemes d'humidite dans les batiments

Treats the causes of deterioration in buildings, thermal bridges, the indoor climate, data for the design and execution of buildings and living conditions in rooms. Section headings are The formation of moulds, Humidity in buildings, The temperature factor, tau, as a criterion of the thermal quality of thestructural elements, Conditions of occupation of buildings, Thermal bridges, Natural ventilation of buildings, Conclusions, Advice.