Study of Ventilation and Carbon Dioxide in an Office Building.
Study of Ventilation and Carbon Dioxide in an Office
Building.
(779 K)
Nabinger, S. J.; Persily, A. K.; Dols, W. S.
ASHRAE Transactions, Vol. 100, No. 2, 1994.
Keywords:
office buildings; ventilation; carbon dioxide; indoor
air quality; monitoring; tracer gas; ventilation rates
Abstract:
Ventilation rates and indoor carbon dioxide levels were
monitored for two years in a new office building near
St. Louis, Missouri. These measurements were made to
assess the operation and performance of the ventilation
system in this building and to investigate the
relationship between indoor carbon dioxide levels and
air change rates. Ventilation rates were measured with
the tracer gas decay technique using an automated
measuring system. Indoor carbon dioxide concentrations
were also measured with an automated system. The
ventilation rates exhibited a dependence on outdoor
temperature that was expected based on the heating,
ventilating, and air-conditioning (HVAC) system's
controls. The air change rates under conditions of
minimum outdoor air intake were about 0.5 air changes
per hour (ach), which is lower than both the air change
rate corresponding to the building design value for
minimum outdoor air intake and the rate that corresponds
to the recommended minimum outdoor airflow per person in
ASHRAE Standard 62-1989. The indoor carbon dioxide
concentrations were generally lower than the 1,000-ppm
guideline in Standard 62. The relationship between the
indoor carbon dioxide levels and the building air change
rates was similar to that seen in other office
buildings. These results are presented as part of a
discussion on the use of equilibrium analysis of carbon
dioxide concentrations to determine building air change
rates. This discussion points out limitations in the
use of equilibrium analysis of carbon dioxide
concentrations in office buildings.
