air change rate

Assesses the indoor air quality at Oakland Gardens Elementary School in New York City under 3 different ventilation rates. Uses a mobile laboratory to monitor air quality in 2 classrooms, a hallway and outdoors. Parameters measured include air exchange rates, particulates, odour perception, carbon dioxide, carbon monoxide, sulphur dioxide, ozone, nitrogen oxides, radon, formaldehyde and total aldehydes. When the ventilation rate is reduced, carbon dioxide concentrations increase significantly, but do not exceed current occupational standards.

Describes a programme of ventilation measurements performed on a group of energy efficient houses built in the mid-1970's and situated in Abertridwr, S.Wales. Pressurization, tracer decay and British Gas autovent techniques were employed. Results show satisfactory whole-house ventilation rates (0.5 ac/h), but the living room and bedrooms had very low ventilation rates. Some cases showed serious condensation. "Trickle" ventilation installed in 18 of the houses improved internal ventilation patterns and condensation levels were substantially reduced.

Outlines project where 25 representative dwellings from Birmingham Local Authority Housing stocks were monitored before and after energy retrofitting. Findings are presented as a set of case studies encompassing both fabric and infiltration measures. Suggests that simple energy conservation measures are successful but that more sophisticated combinations tend to under-achieve. Ventilation changes in several cases are impaired by increased use of windows and/or permanent ventilation. Where these effects are'nt operating, reductions of between 0.3 - 0.6 ac/hr appear typical.

Describes the measurement of infiltration and air change rates in one flat in an apartment block containing 24 flats. Gives the general principles of the pressurization method and tracer gas method for measuring air change rate and infiltration rate. In this situation uses N2O as the tracer gas and measures concentrations with an infra-red gas analyser. Measures the effects of opening and sealing windows, and of closing internal doors on the air change rate and air movement in the flat.

Gives a brief overview of:< 1. Measurement of air change rate using tracer gas.< 2. Measurement of air leakage using steady state and alternating pressure.< 3. Calculation methods (by hand and by computer) for predicting air exchange in a building.< Indicates where relevant research in these areas is being carried out, and outlines the role of the Air Infiltration Centre.

Analyses an infiltration heat loss calculation in accordance with Standard CSN 06 0210, with regard to the minimum air exchange rate (0.3 ach/hr). Concludes that aeration through windows should be graded for buildings which are differently located in the landscape and thus differently exposed to the wind effect.

Compares the air change rates measured with SF6 and CO2 using the tracer gas decay technique and the fan extraction method over a wide variety of test chamber sizes and mixing systems. Shows that the conventional air handling orportable floor fans can provide adequate mixing for SF6 tracer gas decay measurements of infiltration. Warns that the mixing operation may become the dominant driving force of infiltration during calm climatic conditions. Finds that +-0.08 ach/h is a reasonable measure of experimental error at the 95%confidence level using SF6 as the tracer gas.

Presents the first of two sections of report 34020, detailing measurements carried out over the winter period of 1975/76 in Swiss dwellings with mainly hot water heating and some extract ventilation in kitchens and bathrooms. The aim of the research was to obtain a general picture of air change conditions in typical Swiss dwellings and to determine the effect of influencing parameters. The overall aim was to take a step towards the establishment of more surely founded rules of calculating ventilation heat loss as a function of influencing parameters.

The second of two sections of a report of air change measurements in the winter period 1975/76 of non-air conditioned buildings in Switzerland, chiefly dwellings. Recapitulates the reasons for the research, the theoretical bases, measurement method used and aims of the experimental investigations. Sets outin tables detailed results of measurements carried out in a wide range of Swiss dwellings of different ages, locations, construction, design and type.

Two series of pressurisation and ventilation measurements have been made in a low-energy house. One of the objectives of the work was to assess the extent to which the ventilation pattern of the house could be improved by modifying its leakage distribution. The first series of measurements was interpreted to understand the ventilation pattern and to make recommendations for the modifications. The second series was used to find out the effects of the modifications.