Environmental Engineering Reference
In-Depth Information
mates may be limited to providing heat by radiant heating elements, forced
air furnaces, boilers plus forced air heating coils, heat pumps, etc. The sys-
tems used reflect the building's needs and often its age. Ventilation may be
provided by mechanical systems or, as in many older buildings, by opening
windows (natural ventilation).
In seasonally hot climates, the primary focus of climate control is cooling.
Again, ventilation may be provided by mechanical means or by opening
windows.
The trend in most developed countries is to design and construct build-
ings with year-round climate control. In these buildings, windows are sealed
and cannot be opened to provide natural ventilation. Ventilation must be
provided by mechanical systems. Because ventilation is integrated into the
heating and cooling systems, they are described by the acronym, HVAC
(heating, ventilating, air conditioning). HVAC systems vary in design and
operation (see Chapter 11).
HVAC systems control thermal conditions and air exchange with the
ambient environment, so their operation is a major determinant of occupant
comfort and satisfaction with the indoor environment. Well-designed and
operated HVAC systems are essential to provide occupants with ventilation
air sufficient to dilute human bioeffluents to acceptable levels and, to a
limited degree, control levels of other contaminants as well. Inadequacies in
design and operation of HVAC systems are the primary cause of air quality
complaints in mechanically ventilated buildings.
8.
Plumbing
Plumbing systems are designed to provide a potable water supply, heated
(hot water or steam) or chilled water lines serving AHUs, sprinkler water
supply for fire suppression, static water supply for emergency fire use, and
waste water lines. Heated or chilled water lines are typically insulated. A
variety of insulating materials have been used, including molded gypsum-
containing asbestos. In many older buildings, the plumbing system is the
major site of asbestos-containing materials. Modern plumbing is insulated
with a variety of materials including fiberglass, foamed rubber, molded
gypsum, etc.
Plumbing in nonresidential buildings is subject to a variety of leakage
problems that cause minor stains (and mold infestation) to major flooding.
The former are common; the latter rare. Both are environmental quality
concerns.
9.
Other utilities
In addition to heating, cooling, ventilating, and plumbing, nonresidential
buildings are provided with a variety of utilities including lighting fixtures
and electrical, telephone, and computer wiring. Wiring is typically arranged
to minimize space and resource requirements and is co-located in wiring
runs, pipe chases, hallway plenums, etc.
