Siting
& Form Introduction
Most
of the location, orientation and massing decisions made in
the early stages of design have a profound effect on the energy
and environmental impacts of buildings. This is particularly
the case for solar-responsive, daylighting and natural cooling
design, where early decisions establish the potential for
passive renewable energy use. Other environmental strategies,
such as stormwater management, are also greatly influenced
by site planning.
Solar-Responsive
Design
There are
many direct and indirect benefits of designing buildings that
respond to the sun. However, approaches to shape and orientation
differ depending on the purpose: Is the goal to minimize cooling
loads, or to collect solar energy now or in the future? The
challenge is to ensure that different portions of the building
respond appropriately to these two very different goals, while
integrating them into a functional and elegant whole. Careful
orientation and massing can minimize solar energy entering
the building and greatly reduce cooling loads, especially
for commercial and retail buildings with high internal loads.
This translates into lower energy costs over the life of the
building and less air pollution from electricity generation.
Careful
solar control can also reduce costs for mechanical cooling
equipment often to the point of lower overall construction
cost. Solar control to reduce cooling loads helps provide
year-round comfort, more independence from energy price increases
and less vulnerability to brownouts.
Many Santa
Monica buildings require heating — especially building
with low internal electrical loads, such as multi-unit residential.
Unlike solar
control for cooling, using solar energy for service hot water
(SHW) heating or electricity generation requires maximizing
the exposure of collectors to the sun. This reduces the capital
cost of these systems, which in the past has been relatively
high. Those parts of the building that carry these systems
should be shaped to collect solar energy efficiently.
In Santa
Monica, solar hot water systems are cost-effective for many
uses now. Photovoltaic electricity generation is currently
expensive, but costs are dropping rapidly. “Building-integrated”
photovoltaic (BIPV) systems, which incorporate collectors
into the roof, walls and other building elements, are now
entering the market, replacing conventional exterior finishes
and reducing construction cost. Another trend is to use solar
collectors as window shades — gaining two functions from
the same elements. Ensuring that the building will be able
to take advantage of free, renewable solar energy in the future,
when capital costs will be lower, is a prudent strategy.
Daylighting
Design
Building
occupants place a premium on natural light and a view to the
exterior. If carefully admitted and controlled, daylight enhances
the visual quality of interior spaces, and offers many psychological
benefits that are difficult and expensive to replicate with
electrical lighting. Natural light has inherent variability
and unique spectral qualities that reveal and highlight interiors.
Providing naturally lit interiors has been shown to increase
occupant satisfaction, lower absenteeism, and improve worker
productivity and retail sales.
Daylighting
design has a major impact on the form and orientation of buildings.
First, the building and its openings — windows, skylights
and roof monitors — must be oriented to allow light to
enter interior spaces, without causing glare or visual discomfort.
As well, design for daylighting can constrain the depth of
buildings, to allow natural light in most occupied spaces.
This limitation can be greatly eased by the use of light distribution
strategies, such as light shelves and ceiling slopes, that
extend the depth of daylit space.
A view to
the outdoors is important for occupants’ sense of well-being,
since it provides cues on orientation, time of day and weather.
Providing visual contact with the exterior from most interior
areas attracts and retains tenants and staff — but also
places limitations on building depth and interior partitions.
Natural
Ventilation and Cooling
Natural,
or passive, ventilation and cooling uses wind and the buoyancy
of warm air to provide comfortable conditions within buildings
during hot periods. When carefully combined with daylighting
and thermal mass, natural ventilation can greatly reduce the
cooling load in buildings, and minimize or eliminate the need
for mechanical cooling in most circumstances in Santa Monica.
Natural
ventilation and cooling offers many advantages over artificial
air-conditioning. First, although all major manufacturers
are introducing equipment that uses less damaging refrigerants,
often with equal or better energy efficiencies than existing
chlorofluorocarbon (CFC) equipment, many still use refrigerants
that damage the ozone layer and are slated to be banned in
the near future. Natural cooling eliminates this concern.
Second, regardless of the refrigerant, mechanical cooling
equipment consumes fossil fuels during use, with their associated
operating and environmental costs. Third, there is growing
market evidence that building occupants prefer natural ventilation
over that provided by mechanical air-conditioning systems
— providing an advantage when selling or leasing a building
or attracting and retaining employees.
Santa Monica
has ideal conditions for natural ventilation and cooling.
The prevailing breezes are consistently on-shore from Santa
Monica Bay, from the west-southwest and west throughout the
year. These winds are most consistent when cooling requirements
are high, when air temperatures are higher and the sun is
most intense. As well, Santa Monica’s street grid and
lot orientation are at right angles to the prevailing on-shore
winds, allowing the use of natural ventilation for most locations.
However,
building form and orientation must be shaped to take advantage
of natural cooling opportunities. First, the building must
be located and shaped considering the prevailing wind. Air
inlets are best placed in upwind exposures, where the pressure
is highest. Air outlets are best placed in downwind, low-pressure
exposures. Spaces with single-sided natural cooling must be
narrow; cross-ventilation requires paths for air to move through
one or more rooms in the building. Interior walls are best
placed where they don’t block airflow. As well, natural
cooling is enhanced by tall spaces, that allow heated air
to rise out of the occupied zone and out of the building.
Finally, thermally massive floors and walls store the cold
from night air in effective night ventilation strategies —
which affects structural design.
Integrating
Design Strategies
Many of
these features — openings to the outdoors, high and narrow
spaces, and interior wall placement — are the same as
those of daylighting design. Combining these two strategies
can reduce the cooling loads of Santa Monica buildings to
the point where artificial air-conditioning is not necessary,
and artificial light is required only as it gets dark. The
result: much lower air pollution and consumption of non-renewable
energy.
Most of
the Recommended Practices in this chapter are aimed primarily
at reducing energy consumption, but they also offer indoor
environmental quality benefits. However, they only establish
the potential for energy savings and its environmental benefits;
these strategies must be coordinated with envelope, mechanical
and electrical systems design and control strategies to ensure
these savings are realized.
Solar-responsive,
daylighting and natural cooling design offer significant environmental
benefits, and they work best when combined. The most effective
design strategy is a narrow floor plan, allowing most interior
spaces a direct connection to the outdoors. Narrow spaces
provide the opportunity for increased daylight, better views
to the exterior and more potential for natural ventilation.
Stormwater
Management
Pollution
of Santa Monica Bay by stormwater runoff is one of the most
pressing and difficult environmental problems in the Los Angeles
basin. Building sites have a role to play in reducing the
amount and contamination of stormwater runoff. The Santa Monica
Municipal Code ordinance 7.10.060 requires that building developers
submit an Urban Runoff Mitigation Plan, showing how the site
will address this issue. The most effective approach is to
limit the amount of impermeable surfaces on the site, since
permeable surfaces both reduce peak stormwater runoff, and
treat stormwater pollutants.
Runoff from
parking areas and vehicle lanes in particular contain a wide
variety of contaminants, including lead, asbestos, oil, grease
and gasoline. Biological and mechanical methods of treating
these contaminants, and reducing the amount of stormwater
carrying them to the Bay, are summarized in
SFa:
SMMC 7.10.050:
Submit an Urban Runoff Mitigation Plan to the Engineering
Division TRa:
SMMC 5.20.080:
Install Clarifiers or Oil/Water Separators on Drains from
Service Bays and Parking Areas LAa:
SMMC 7.10.050:
Minimize Stormwater Runoff to Impermeable Areas
