Tracer Technology Group

Building Ventilation

Air exchange rates in buildings are important for understanding indoor air quality. We use PFT technology to measure exchange rates in two ways. A source releasing PFT at a known rate can be placed in a building. The tracer concentration in the building is given by:

 

 

 

 

 

Once the concentration is allowed to equilibrate, tracer release rate is balanced by the air exchange rate, and the exchange rate is equal to the emission rate of the tracer source divided by average tracer concentration.   Tracers are released using permeation sources and sampled using activated charcoal filters.

A second technique is to release known amount of tracer over a short period of time and measure the concentration decay rate. The ability to use multiple tracers means that multiple zones in a building can be studied simultaneously and crossover between zones can be measured. Samples can be taken actively or passively. We have made these measurements over multiple time scales from minutes to months. We are currently involved in a study in the Netherlands where one-year samples are being collected.

Infiltration rates are also important in determining the effects of Radon, VOCs, and other substances on the air quality in buildings. PFTs sources placed in the ground could be powerful tools in quantifying these rates.

We have used PFT technology to measure the effectiveness of air filtration systems in Nuclear Power Plant Control Rooms and are in the process of having our techniques certified by the Nuclear Regulatory Commission (more).

 

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Last Modified: May 14, 2008
Please forward all questions about this site to: Linda Satalino