Experimental characterization of ventilation systems in buildings

Abstract

Tracer experiments, involving sulfur hexafluoride, were used to obtain quantitative data regarding actual residence time distributions in rooms and hallways, and contamination caused by reentry of laboratory fume hood exhausts into a building. Application of a mixing factor, k, was found to be of use, and measured values ranged from 0.3 to 0.7 in small rooms without fans. One experiment involved a roof exhaust with ventilation intakes both on an adjoining roof and at ground level; in this experiment more of the exhaust reentered the ground level intake of the same building as compared to the roof intake of an adjoining building. In another experiment, 20% of the fumes exhausted were found to reenter the ventilation system.

Air Change Measurements Using Tracer Gases: Methods and Results. Significance of air change for indoor air quality

“…After Gregory's observation in 1962, that sulphur hexafluoride (SF 6 ) can be measured reliably on the nanogram scale with electron capture detection -ECD (Gregory, 1962), it has been widely used for air infiltration measurement in buildings since the early 1970s (Drivas et al, 1972;Hunt & Burch, 1975). Of all candidates, the characteristics of SF 6 are nearest to the ideal of a tracer gas.…”

The tracer gas technique--a useful tool for industrial hygiene.

“…(8,16,17), to evaluate the significance of various in-plant pollution sources with the determination of the emission index (11), to conduct air flow measurements in ducts (20), and to study the reentry of pollutants (6,12).…”

An Inexpensive Remote Sequential Air Sampler

“…To obtain manual ambient air samples (sometimes called grab samples), previous studies have used evacuated stainless steel containers, 5 plastic bags, 6 ' 7 and plastic squeeze bottles. 8 ' 9 However, none of these methods have been easily or inexpensively adapted to an automated sampling system at the time this manuscript was submitted for review. The purpose of this note is to describe a new, inexpensive, and fairly simple device which functions as a remote sequential air sampler.…”