AIVC - Air Infiltration and Ventilation Centre

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Natural ventilation of modern tightly constructed houses.

Presents results of a survey of natural infiltration rates in 2 identical modern homes-one gas fuelled and one electric-over aperiod of a year. Infiltration rates were determined by releasing tracer gas, usually ethane, into the main return duct and measuring concentration every half hour. Discusses results and dependence of infiltration rates on wind speed and direction. Gives preliminary result that wind probably exerts agreater effect on infiltration than any other variable.

Air leakage characteristics of low-income housing and the effectiveness of weatherization techniques for reducing air infiltration

Reports measurements of air change rates made on approximately 250 dwellings, occupied by low income households in 14 cities, in all major climatic zones of the United States. Two types of measurements were used : a tracer-gas decay technique using air sample bags and a fan depressurization test that measures induced air exchange rates. Shows that for this group of dwellings natural air infiltration rates have an approximate lognormal distribution.

Infiltration in residential structures

Briefly reviews methods of estimating infiltration rates in dwellings. Describes tracer gas method using methane. Gives results of measurements of air change rate made in houses in Minneapolis, Kansas and Denver. Concludes that technique works well for measuring residential infiltration.

Measurements of the ventilation of dwellings.

Reports 312 measurements of ventilation rate in 31 rooms in old and new blocks of flats, 3 villa residences and a modern university building, made using coal gas as a tracer. Describes buildings and gives main results. Examines effect on air change rate of sealing flues and gratings, opening windows and weather conditions. Finds outside wind speed has most influence on ventilation rate. Discusses recommended standards of air supply.

Indoor air pollution due to chipboard used as a construction material

Chipboard is a common building construction material which continuously emanates formaldehyde. Reports measurements of concentrations of formaldehyde in 24 rooms in 23 Danish dwellings where chipboard was used for walls, floors and ceilings. Gives results in table 1 of concentrations underdifferent combinations of temperature, humidity and ventilation rate. Finds average concentration of 0.62 mg/m3 and in some rooms concentration exceeded the German threshold limit for occupational exposure. Develops mathematical model for the room air concentration of formaldehyde.

Adventitious ventilation of houses.

Describes the research being undertaken by the British Gas Corporation on adventitious ventilation. Outlines a test house programme which has quantified adventitious areas for both room components and progressively sealed rooms in dwellings of varying age and construction. Describes a model scale approach to natural ventilation aimed at predicting room air movements and ventilation rates. This work is compared with full-scale results and theoretical models.

Measurement of infiltration in two residences part 1: technique and measured infiltration.

Reports investigation of air infiltration in two residences using helium as a tracer gas. Describes the residences, instrumentation and test procedure. Gives results of decay rate of tracer gas and measured infiltration rates. Summarizes test conditions in tables of temperature, wind speed and direction, internal to external pressure differences and height of the neutral zone. Concludes that in houses with warm-air heating systems a single helium analyzing cell in the return air-stream would provide a satisfactory indication of house infiltration rate.

Comparative measurements of wind pressure on a model of the full-scale experimental house at Aylesbury, England.

The two-storey house at Aylesbury, England, built by the Building Research Establishment for the full-scale measurement of wind pressures has been modelled at 1:500 scale in a boundary layer wind tunnel to verify the reliability of simulation forlow-rise buildings. Describes wind tunnel tests of buildings models of 5 and 22.5 roof slope. Compares surface pressure measurements with full-scale data for various wall and roof locations. For the model terrain best modelling conditions, the results show agreement which is encouraging.

Shelterbelt influences II, the value of shelterbelts in house heating.

Describes experiments aiming to estimate the protection afforded by a shelterbelt on the plains area of America. Describes three test houses and gives test results. The three houses were unprotected, partially protected and closely protected by a slat fence. Gives basic data in the form of fuel use, wind and temperature. Concludes that the reduction in wind speed by windbreaks is of the general order of 35% with a proportional saving in fuel. Finds that the area of tree shelterbelts has themost important effect on the degree of wind reduction.

The measurement of wind pressures on two-storey houses at Aylesbury.

Reports project to measure wind pressures on low-rise buildings. Describes site and houses in the estate selected for investigation. Gives details of an associated experimental building. Outlines positioning of the pressure transducers andgives details of the cabling and the reference pressure system. describes velocity measurement, recording equipment and methods of calibration, processing and analysis. Gives details of records taken in tabular form.