AIVC - Air Infiltration and Ventilation Centre

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Indoor air pollution.

Indoor concentrations of pollutants often equal or exceed outdoor concentrations, and since most people spend 90% of their time indoors this constitutes a health threat much greater than that posed by outdoor pollution, which has received most of the attention in the U.S.A. The problem has been made worse by energy conservation measures which reduce ventilation. Thisarticle reviews recent research findings and their implications for pollution control programmes, and considers the further research that is needed.

Changes of indoor climate in dwellings because of renewal of windows and tightening of joints. Indeklimaforandringer i bolige efter vinduesudskiftninger og fugetaetning.

In order to reduce heating energy consumption, single glazed windows are commonly replaced by double glazing and joints tightened in Danish dwellings. Reports investigation of the influence of such tightening of dwellings on the indoor climate. 25 tightened and 25 not-tightened identical flats were investigated. Finds an improvement in thermal climate and a significant reduction in heat consumption in the retrofitted flats. Finds absolute humidity of indoor air was significantly higher in improved flats, probably due to reduced ventilation.

New regulations on radiation in buildings. Nya bestammelser om stralning i byggnader.

Tests carried out during the sixties and seventies showed that there was a correlation between lung cancer and the existence of radon gas in mines and that there was radon gas in homes built of aerated concrete based on slate. This led to political activity with regulations for limits on emanation in new, re-built and existing buildings. Provisions were also made for grants to help house owners finance the improvements specified.< In the new bye-laws, SBN 80, gamma radiation is not to exceed 50 mu.R/h, the radon content is not to exceed an annual mean of 70 Bq/cu.m.

Investigating CO2 concentrations in a classroom. Untersuchung der CO2 Konzentration in einem Klassenraum.

Discusses acceptable levels of CO2 contamination in occupied rooms. Describes measurements in a classroom over 3 days using an infra-red analyser with natural ventilation via the windows. Illustrates curves for CO2 concentrations in 8 graphs for closed windows. Notes that limiting value of 0.1% by volume CO2 (1000ppm) is reached in from 5 to 15 minutes. Repeated sudden ventilation by opening windows is not practicable. Evaluates air change rate. Concludes energy saving for ventilation in heavily populated rooms is only attainable by mechanical ventilation with heat recovery.

Requirements for ventilation.

Reviews ventilation criteria for occupied buildings. Considers minimum ventilation for the control of carbon dioxide, odours, cigarette smoke, moisture and radon. Discusses future work to improve ventilation routes.

The airtightness of a sound-proof dwelling house and its ventilation plan.

Reports investigation of the air quality in a sound-insulated dwelling house. Measurements of ventilation rate and concentrations of CO, CO2, and NO2 were measured in a tight sound-insulated dining-kitchen, with and without the operation of a gas range, instantaneous hot-water heater and ventilation fan. Finds that natural ventilation was inadequate when the gas appliances were operating and recommends that an instantaneous gas hot-water heater should be provided with an exclusive air exhauster.

Design of ventilation systems in low infiltration detached house.

The air-tightness of various houses is revealed by testing with the pressurization method, and the equivalent open area of air infiltration per floor area is proposed as the index of air-tightness of a house.< Then the heating system, indoor air quality, indoor temperature and humidity and house planning which affect the ventilation design are discussed in connection with the air-tightness of a house.

Contaminant control in the built environment: state of the art summary.

The reduction of ventilation in buildings as an energy saving measure may result in a deterioration in indoor air quality. Suggests use of contaminant control devices and summarises devices available. These are filters, electrostatic precipitators, mechanical dust collectors, scrubbers, and contaminant combustors Suggests five areas where further research is necessary.

The effect of reduced ventilation on indoor air quality and energy use in schools.

Indoor air quality in an air conditioned California high school has been measured over a variety of ventilation rates ranging from 13.3 cubic feet of outside air per minute for each classroom occupant to approximately 1.5 cfm per occupant.< Parameters measured include outside air supply rate, the occupants' subjective perception of indoor air quality, airborne microbes, carbon dioxide, carbon monoxide, nitrogen oxide, sulphur dioxide and ozone in two classrooms, a halland outdoors.

An investigation into the air quality of three working men's clubs.

Working men's clubs are commercially thriving organisations catering for a wide range of social activities commonly held in a single room holding 300-400 people. Packaged air conditioning is being introduced into Working Men's Clubs to provide air recirculation and cleaning when the buildings are occupied. Air cooling and dehumidification is also available. One club was dissatisfied and an investigation was started to investigate the difference. Measurements showed that the unsatisfactory installation was unusual in two ways.

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