Problem buildings - Indoor Environmental Quality - page 206

evaluated relative to their potential role in contributing to health and/or
comfort complaints in buildings.
Factors that have significant effects on human comfort, such as temper-
ature, ventilation, air flow, and in some cases R.H., are mechanically con-
trolled by environmental/climate control systems. Increasingly, new build-
ings are being designed to provide year-round climate control, and older
buildings are being retrofitted to do so. Systems which provide heating,
cooling, and ventilation are described by the acronym HVAC. As indicated
in Chapter 11, many factors associated with the design, construction, main-
tenance, and operation of HVAC systems have the potential to cause, or
contribute to, building-related health and comfort complaints.
Human comfort is affected by a number of physical factors, the most
important of which are thermal conditions, characterized by air temperature,
R.H., air movement, and the radiant effects of indoor surfaces. Relative
humidity and air velocity may have effects on comfort that are independent
of thermal effects.

1. Thermal conditions

Occupants of buildings who report illness symptoms and dissatisfaction
with air quality work in environments where a number of coexisting factors
influence their sense of well-being and personal comfort. Dissatisfaction with
temperature and other factors that affect thermal comfort in buildings is
common. This can be seen from results of systematic studies conducted in
the USEPA headquarters and Library of Congress buildings ( Table 7.6 ) .
Dissatisfaction with environmental conditions was relatively high, with tem-
perature and lack of air movement being particularly significant sources of
dissatisfaction in the Waterside Mall building of the USEPA headquarters
complex. Waterside Mall occupants also reported higher prevalence rates of
SBS-type symptoms.
A number of epidemiological studies have attempted to evaluate work-
space temperature and SBS-type complaints. Varied results have been

Table 7.6 Occupant Dissatisfaction with Environmental Conditions in

USEPA Headquarters Buildings and the Library of Congress

Environmental parameter (% dissatisfied)

Location Temperature Relative humidity Air movement

Library of Congress 39 26 43

USEPA buildings
Waterside Mall

57 36 53

Crystal City 40 37 48

Fairchild 40 33 41

Total 53 36 49

Source: From Selfridge, O.J., Berglund, L.G., and Leaderer, B.P., Proc. 5th Internatl.

Conf. Indoor Air Qual. Clim ., Toronto, 4, 665, 1990.