Environmental Engineering Reference
In-Depth Information
D. Building operation and maintenance
Nonresidential buildings such as office, commercial, and institutional build-
ings are typically large, with relatively complex systems (plumbing, lighting,
HVAC) that need to be properly operated and maintained. Many buildings
and their systems are often poorly operated and maintained and are therefore
subject to a variety of problems, including poor thermal control, inadequate
ventilation, inadequate cleaning, recurring roof and other structural leaks,
and mold infestation. Poor building and building systems operation and
maintenance may be due in part to the complexities involved (particularly
HVAC systems), inadequately trained or motivated facilities service staff,
lack of commitment by building management, and inadequate building
operation/maintenance resources. School buildings, in poor (and sometimes
not-so-poor) school districts, are particularly subject to resource limitations.
In such instances maintenance is often deferred. As a result, poorly operating
mechanical systems, water damaged/mold infested materials, and inade-
quately cleaned surfaces are common.
E.
Occupant densities and activities
Nonresidential buildings are distinguished by varied occupant densities and
activities. Projected occupant densities are a major building design factor.
They determine space requirements and ventilation needs. Highest occupant
densities occur in school buildings and sports arenas.
Occupant activities vary from building to building, as well as within a
single building. In office buildings, these may include general clerical work,
using office equipment, preparing/serving/eating food, printing, etc. They
may also include maintenance activities such as cleaning floors and other
horizontal surfaces, repainting, repairing problem systems, and pest control,
among others. In schools, they include teaching/learning, clerical/adminis-
trative work, food preparation/eating, athletic activities, art and shop
projects, and maintenance activities such as floor waxing and pest control.
Occupant activities may, in many cases, be a source of contaminants that
affect IAQ and the cleanliness of building surfaces. They may also affect the
health and well-being of occupants engaged in such activities and/or the
general building population.
F.
Exposure concerns
Nonresidential buildings are subject to a number of contamination, exposure,
and health concerns. These include: elevated bioeffluent levels associated
with high occupant densities and inadequate ventilation; emissions from
office equipment and materials; cross-contamination from contaminant-gen-
erating areas; re-entry of building exhaust gases; entrainment of contami-
nants generated outdoors; contamination of AHUs by organisms/biological
products that can cause illness, e.g., hypersensitivity pneumonitis, humidifier
