AIVC - Air Infiltration and Ventilation Centre

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ventilation rate

Impact of varying area of polluting surface materials on perceived air quality

The impact of the concentration of pollutants in the air on emissions from building materials is the subject of that study.Different building materials were studied in ventilated small-scale test chambers. The experiment allowed the changing of the dilution factor or the changing of the area factor.The results showed that more ventilation in a given space may increase the emissions from the inner surfaces.

Natural ventilation of light well in high-rise apartment building

A large opening has to be designed at the bottom of a Void (light-well in high-rise apartment building) in order to keep the indoor air quality (IAQ) acceptable, because of the exhaust gas discharge of the gas water-heater. This paper presents a simple calculation method of the ventilation rate induced by wind force and thermal buoyancy through openings at the bottom, along with heat sources such as water-heaters.

Standard 62 and smoking

This article presents how ventilation and air quality in smoking spaces are being treated by ANSI/ASHRAE standard 62, Ventilation for Acceptable Indoor Air Quality. Historical information is given about environmental tobacco smoke and ventilation requirements in the standard since its first issue in 1973. The status of the 31 addenda to the 1999 version of the standard, some of them being included in the 2001 version, others still being in discussion or in the process to be adopted, is explained. Among them are four smoking-related addenda : 62e, 62g, 62o and 62ag.

Worker performance and ventilation : analyses of time-series data for a group of call-center workers

The aim of a study is to determine if on site, in a call-centre of 4600 m2, a correlation can be found between ventilation rate and performance of worker. No clear effect of ventilation rate on worker performance has been found in this case on the air flowrate variation range (12 to 48 l/s). Yet some improvements of performance are shown at very high ventilation rate.

A case of sick building syndrome caused by incorrect ventilation design of the tight building

A survey was conducted in a new office building in Beijing (China) with mechanical air supply and natural exhaust, in which sick building symptoms were reported. Measurements and data from a questionnaire suggested that ventilation was insufficient.

Carbon Dioxide Levels and Summertime Ventilation Rates in UK Schools

Measurements of metabolic carbon dioxide concentration made in four classrooms in two schools are reported for both occupied and unoccupied periods. Measurements were taken for approximately one week in each classroom during the unheated season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations that are far beyond the guideline value of 1000 ppm (the maximum concentration during the occupied period was 3756 ppm). Calculated air supply rates vary from unacceptably low levels, to rates that are in line with guidance.

Carbon Dioxide Levels and Ventilation Rates in Schools

In the following, measurements of CO2 levels in seven classrooms in four schools are reported. Measurements were taken for approximately one week in each classroom during the heating season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations which are far beyond the guideline value of 1000 ppm (the average concentration during the occupied period was 1957 ppm). In some classrooms the level exceeded the range of the detector (4000ppm).

Tracer gas techniques for measurement of ventilation in multi-zone buildings - a review

Five different techniques of tracer gas measurement are reviewed in order to determine the total ventilation airflow rate as well as air distribution in the room, on site or in laboratory. Examples of applications are given insisting on the two most recent techniques.

Analysis of ventilation rates for the BASE study : assessment of measurement uncertainty and comparison with ASHRAE 62-1999

The aim of the BASE study was to collect air quality data for office buildings in the USA, using air flow rates measurements or tracer gas (CO2) methods. Results for 100 buildings are summarized : 11 % of buildings have outside air ventilation rates below ASHRAE recommendations. The accuracy and the limitations of the measuring methods are also analyzed. CO2 tracer gas method best represents the ventilation rate.

Outdoor and return airflow mixing with parallel dampers

Thermal mixing of two air streams (outdoor air flow and return air flow) with different temperatures and velocities was studied experimentally in a chamber as it exists inside air handling units, with different adjustments of parallel air dampers. Results show how and where the mixing occurs in the chamber. Indications about the influence of the air dampers adjustment on mixing effectiveness are given.

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