AIVC - Air Infiltration and Ventilation Centre

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air change rate

Determination of air change rates by CO monitoring of supply and exhaust air concentrations.

Describes a method for determining the air change rate in a room or a building by continuous monotoring of the CO concentration in both supply and exhaust air. By using a mass balance equation, the indoor concentration of CO can be numerically calculated for various air change rates. The value of the air change rate used in the equation that gives the best correlation between measured concentration and calculated concentration provides an estimate of the air change rate for the volume studied.

Air quality and ventilation rates in school classrooms I: air quality monitoring.

Indoor air quality was monitored at two schools in Essex, UK (located on the same site) during the week 3--7 November 1997. The objective was to determine whether the ventilation rates within the buildings were adequate to provide acceptable air quality to the occupants. Airborne carbon  dioxide concentration was determined using continuous infrared detectors. A class base in each school was monitored for a two-day period. Occupancy patterns and window/door opening were observed during the first day of each period. Air temperature was also recorded.

Indoor air quality for residential buildings.

ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation traditionally was not a major concern because it was felt that between operable windows and envelope leakage, people were getting enough air. In the quarter of a century since the first oil shock, houses have become much more energy efficient. At the same time, the kinds of materials and functions in houses were changing in character in response to people's needs.

Estimation of air exchange rates in Kuwaiti residential buildings.

Air exchange rates of ten residential buildings were measured according to ASTM-E741-83 using SF6 as a decaying tracer. Air exchange rates were also predicted based on the characteristics of the HVAC system, openings (such as windows), leakage areas, pertaining average wind speed, average indoor/outdoor temperature difference and wind and stack coefficients. It was found that measured air exchange rates were higher by 34% than those predicted if the literature coefficients were used.