Reports on 2 methods of measuring ventilation rates in the 8-storey San Francisco Social Services Building, using occupant-generated CO2 as a tracer gas. Measures CO2 concentration at regular intervals on the first floor using an infra-red gas detector. Uses the tracer gas decay method and the constant concentration (integral) method to determine ventilation rates. Finds that the CO2 decay method compares favourably with both SF6 tracer gas measurements and with air-flow measurements in the ducts.
Compares the air change rates measured using the decay method with several different tracer gases. Tracer gas measurements were conducted in a tightly sealed room where constant air leakage rates were maintained using an exhaust fan. Tracer gases investigated were CH4, CO, CO2, N2O and SF6. Agreement between tracer gas measurements and measured flow rates of the exhaust fan was very good for CH4, CO and N2O. The agreement was also satisfactory for CO2 and SF6, but the scatter in tracer gas data was much greater then it was for the other three gases.
Reports on the metabolic CO2 method for ventilation measurement which has been extended from mechanically ventilated rooms to naturally ventilated ones. The analysis, which under some circumstances is also relevant to tracer gas decay measurements, allows assessments of the individual incoming flows of air.
Mechanical ventilation systems usually provide a fixed quantity of "fresh" air to a building space based upon the maximum number of people expected to occupy that particular space. When the use of a building space is below its design maximum, the amount of outside air brought into that space can be reduced, thus generally also reducing energy consumption through lower heating and cooling loads. One method of determining the necessary ventilation rate for aparticular space is to utilize an air quality detector (eg CO2 or O2) sensitive to building occupancy and activity load.
Uses occupant-generated CO2 as an indicator of the actual ventilation rate in a San Francisco office building. Employs two techniques, a decay method and an integral method, and measurements are conducted simultaneously at several locations. The decay method compares favourably with the conventional measurement methods in both the all-outside-air and recirculation modes, whereas the integral method shows a considerable deviation from the other methods in the recirculation mode.
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.
Describes detailed experimental analysis of the low energy Plainevaux House with regard to:< 1. Air infiltration, measured by the decay rate of CO2 tracer gas< 2. Air tightness, measured by the fan pressurization technique< 3. The evolution of inside temperature in a period of no-heating< 4. The corresponding air contamination.
Presents new data acquired by experiments on the ventilation rates and the indoor air pollution caused by combustion in the dining-kitchens of sound-insulated houses. Ventilation rates were measured by means of tracer gas decay, using CO2 and CO as the tracer gases. Indoor air pollution was estimated from the elevation of CO and CO2 levels, and the effect of supply or exhaust fan systems on the control of ventilation was deduced from the level of air pollution and ventilation rates.
The primary aim of the project is to describe and document a measurement method suitable for checking whether minimum requirements for ventilation efficiency are fulfilled after a ventilation system has been regulated. The project concentrates on occupied areas with mechanical ventilation such as dwellings,offices and schools. Excludes industrial buildings since special conditions such as ventilation rates, polluting processes and local extraction apply to these. Defines ventilation efficiency, describes equipment and measurement with CO2, N2O, SF6, Kr85.
Reports measurements of indoor air quality in an air conditioned California High School over a range of ventilation rates, ranging from 13.3 cu.ft. of outside air per minute for each classroom occupant to approximately 1.5 cfm per occupant. Parameters measured include outside air supply rate, theoccupants' perception of indoor air quality, microbial burden, concentration of CO2, CO, NOx, SO2, O3 in two classrooms, a hall and outdoors.
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