SYNOPSIS: Density
is not equal to the leadership language required to define shelter policy and planning
strategy within The Built Domain. It is a measure of residential activity that cannot
lead the physical results constructed to shelter any activity in the Built
Domain. It has caused great confusion, contradiction, disagreement, and
distrust within and between those in the public and private sectors. It must be
replaced with a language that can more accurately measure the past, evaluate
the present, and predict the future. We need a language that can lead us to the
goal of shelter for the activities of growing populations within a geographically
limited Built Domain that protects their quality and source of life – The
Natural Domain.
NOTE 1: This
essay was originally published in September, 2010. This revision is based on
the information provided in the book entitled, The Science of City Design,
by Walter M. Hosack, 2016 and available from Amazon.com. The equations
presented are new and the differences are significant.
NOTE 2: All
figures and tables are located at the end of the text.
NOTE 3: This essay has been substantially revised by, "The Shelter Components of Capacity, Intensity, Intrusion, and Dominance" written in July, 2021. Some content has not been included, however.
The
development capacity of land is equal to the gross building area that can be
constructed per shelter acre available. (Shelter area is calculated in cell F
and G17 of Table 1.) Gross building area is a volume that can be occupied by one
or more activities given the floor quantity chosen. The percentage of building
cover and pavement cover provided per acre is referred to as “intensity”.
Intensity is offset by the percentage of unpaved project open space provided. At
one end of the intensity spectrum is a small building on thousands of acres. At
the other is a high-rise on one acre. In both cases, the square feet of shelter
and pavement constructed per acre of land involved is an indication of the
physical intensity introduced.
Activity
is referred to as “land use”. The relationship of shelter capacity, condition,
and social activity to geographic location affects economic stability and
social acceptance. In other words, shelter capacity, condition, and location produce
levels of physical intensity, social activity, and economic contribution that
affect our quality of life within The Built Domain.
The
Movement and Life Support Divisions of our Built Domain convert and serve land
for the Shelter Division. The square feet of building area and pavement introduced
per acre determines the population that can be served, the scope of activity
that can be conducted, and the economic contribution that can be expected. The
social open space that remains contributes to the quality of life provided
within The Built Domain. In other words, the physical, social, and economic
characteristics of intensity not only affect the physical, social,
psychological, environmental, and economic welfare of a population within The
Built Domain; but the survival of its source of life beyond.
Six
building design categories encompass most, if not all, of the shelter provided
on the planet. They are:
1) G1: Buildings
with surface parking around, but not under the building
2) G2: Buildings
with surface parking around and/or under the building
3) S1: Buildings
with structure parking adjacent to the building on the same parcel
4) S2: Buildings
with underground parking
5) S3: Buildings
with structure parking at grade under the building
6) NP: Buildings
with no parking required
The
parking structure options may have supplemental surface parking, but when
present, the building is classified by the parking garage configuration
present. These building categories may be occupied by any activity group that
complies with the local building and zoning codes. The point is that shelter
classification begins with the parking design category involved, and each
category has shelter capacity limitations that are dictated by parking design
specification decisions. For instance, parking design specification decisions
have been entered in cells F33-34 of Table 1. Twenty-three other decisions have
been entered in the remaining specification boxes of Table 1.
A
set of optional percentage decisions are illustrated by the values entered in
the boxes of the Land and G1 Modules of Table 1. There are fifteen boxes and
each value entered in a box represents a design decision that can be modified
to test options. The equations in Col. H of Table 1 convert these decisions to square
foot area implications in Col. G. The objective of the algorithm is to identify
the shelter area available in cell F17 and the core buildable land area
available in cell F32.
The
master equation in cell A37 correlates the specification data entered and
calculated in the Land and G1 Modules of Table 1 with the floor quantity
options entered in cells A42-A51. Shelter capacity alternatives are predicted
in cells B42-B51 of the Planning Forecast Panel. The remainder of the panel
predicts the implications of the shelter capacity forecasts in Col. B using the
secondary equations on line 41. This panel illustrates a few of the many
implications that can be forecast as a function of a gross building area
prediction.
Table
1 illustrates the 16 decisions required to expose options and lead the G1
Design Category toward a desired objective. A change to one or more of the
specification values in Table 1 will produce a new forecast of options in Col.
A of the Planning Forecast Panel, and hundreds of options can be predicted in a
very short time. The point here is that the gross building area predicted can
be occupied by any permitted activity, and that a single density requirement is
not a substitute for the 16 decisions required to lead performance toward a
desired objective.
The
gross building area options forecast in Col. B of the Planning Forecast Panel
are used to produce the shelter capacity forecast in Col. F. These capacity options
are used to calculate intensity, intrusion, and dominance measurements in
Columns H and J. These four measurements are like the first blood pressure
readings. They indicate the impact level present or proposed. I can only hope
that continued measurement and evaluation will lead to impact parameters that can
improve urban health, safety, and welfare.
Intensity
options are defined by stating the design categories and specification values being
considered. A leadership decision establishes an objective by defining the
design category and specification values selected for further architectural
definition and context refinement. Before refinement, however, the impact
selection and its 16 specification decisions represent a massing definition.
When massing compositions are combined, the product is referred to as urban
form; and a plan for urban form determines the shelter capacity of a Built
Domain. Design specifications and impact measurements make it possible to
evaluate, diagnose, and prescribe urban form one project at a time. When a Built
Domain is geographically limited, the quality of life within these limits will
be a function of the definitions chosen in relation to the population size involved
-- and the natural environment preserved.
A
DESIGN PRINCIPLE
The
G1.L1 equation in Table 1 reveals a design principle when the gross building
area values in Col. B of the Planning Forecast Panel of Table 1 are mapped. It
can be formally expressed in the following terms:
When the G1 Design Category is considered, the rate of increase in
gross building area declines at an accelerating rate as the number of building
floors increase.
Figure
1 illustrates this principle and clearly shows the dramatically decreasing rate
of increase in gross building area as building height pushes above five floors.
Figure 1 is based on the provision of 40% open space. If this were reduced to
15%, the efficiency profile in Figure 1 would show the same rapidly decreasing
rate of increase in development capacity, but start at a higher point on the
Y-axis. In fact, any change to design specification values will alter the
intensity and context created, but its impact remains a matter of opinion because
it has not been measured and evaluated.
Figure
1 confirms the intuition of many designers and converts this intuition to knowledge
that is a function of the Table 1 forecast model. The context implications of
design specifications, including open space requirements, and the intensity
options produced remain to be explored; but there is another point to be made.
Figure 1 demonstrates that planning and design issues can be expressed in
mathematical terms. This has the power to persuade in a political environment
that cannot be avoided. It also improves our ability to collaborate with the
science of others; since the land our planet can donate to shelter, and the shelter
capacity of this land, is becoming an issue of survival.
Figure
1 was based on the gross building area permitted per parking space (a) being
less than the gross area estimated per parking space (s) and 40% unpaved open
space. This is not always the case, and Figure 2 is based on (a) being greater
than (s) and 15% unpaved open space. The design principle still applies, but the
results produced are dramatically different when these values are modified. A
comparison of these results should explain why the gross building area
permitted per parking space and the impervious cover proposed are two of the most
common points of public and private disagreement.
Figure
2 shows that gross building area potential is significantly increased when (a)
is greater than (s). The rate of gross building area increase has not flattened
out at 10 stories, and gross building area potential begins at 85,630 sq. ft.
rather than 38,577 sq. ft. When surface parking is planned or required,
however; the risk of inadequate parking space quantity is significantly
increased when (a) is greater than (s).
When
the five story gross building area is subtracted from the one story gross
building area in each figure, the differences become more apparent. In the case
of Figure 1, the total gain for 1-5 stories is 17,145 sq. ft. The total gain
for 5-10 stories is 3,278 sq. ft. In the case of Figure 2, the total gain for
1-5 stories is 79,043 sq. ft. The total gain for 5-10 stories is 21,749 sq. ft.
Above 5 stories, the gross building area gain per additional floor declines and
becomes increasingly less cost-effective in both cases.
THE POINT
Figures
1 and 2 document a relationship we have intuitively understood for quite some
time. Greater parking space requirements (a) and greater parking areas per
space (s) reduce the area available for building footprint and unpaved project
open space. This reduces gross building area potential. Unpaved open space is
consumed to increase parking areas and gross building area options. (Gross
building area may be occupied by any residential or non-residential activity.)
Parking variances are sought to reduce the parking requirement (a) when open
space consumption does not provide enough additional parking to justify a gross
building area objective. (There may be no objective. It may be a simple attempt
to maximize gross building area potential given the cost of the land.)
Parking
requirements have little research to defend them and can easily be challenged
by the experience of a current applicant’s operations. Unfortunately,
successful appeals can leave deficient parking for a future building owner. In
the worst cases, it can contribute to economic decline, deteriorating
condition, and inadequate public revenue from the acres consumed within a
city’s boundaries.
Figures
1 and 2 are based on the design specification data in Table 1. The (a) value in
Table 1 has been modified to produce Figure 2. The example illustrates the
influence of parking requirements on gross building area potential, but this is
not the underlying point of the discussion.
The
results in Table 1 could not have been predicted by a residential density
regulation; and if they cannot be predicted, they cannot be led to produce
results that avoid excess and decline. Table 2 lists the design categories and
forecast models that can enable us to speak in the language required to lead shelter
toward solutions that protect our quality of life within a geographically
limited Built Domain that protects our source of life. In other words,
residential density is a product of design specification decisions. It does not
make them nor provide design leadership. Table 3 presents a Built Domain classification system that
incorporates the generic design categories of Table 2.
BACKGROUND
Our
ability to shelter populations and activities within a limited built
environment will depend on our ability to balance the artificial world of our
presence with the natural world of our planet; and on our ability to balance a
growing population with the average intensity required. This is an emerging
awareness tormented by conflicting opinion; but fortunately, intensity and
impact can be predicted. The options forecast however, have context
implications that remain to be explored; and research is required to avoid the
oppression intensity and impact can produce.
The
prediction of shelter options will improve when we can quickly forecast the
entire spectrum of intensity alternatives that meet an open space
specification, since open space offsets intensity and is the weight that produces
balance within our built environment. It is also the foundation of a natural
environment that suffers our presence at its discretion. In other words, it is
all about design with space – since open space must be present before details
can be introduced -- and success will depend on our ability to forecast the
implications of intensity options that preserve its presence. We have learned
however, that simply adding open space is not an answer; and we need a scientific method that
can measure context, evaluate implications,
forecast alternatives, and express decisions in precise terms. At this point,
vocabulary will become language with the power to lead the shape and form of
our built environment to the limits demanded by its silent partner -- and to
the quality of life deserved by its inhabitants.
Architecture has always sheltered the activities of its period and
been a product of the knowledge and opinions available. It is no accident that
the current sprawl of architecture reflects our confused relationship to the
land. Opinion has produced indiscriminate regulation and the land is
compromised by the process. We are distracted by the details of compatibility, construction
and appearance — not to mention ownership and sovereignty; but intuition is looking
beyond the environment we build to include the environment we consume.
Balancing these two worlds will depend on our ability to understand impact and offer
options within limits that meet our strategic goals.
Architecture, landscape architecture, city planning, and regional
development have borrowed from the knowledge of others, but need a common language
with greater ability to coordinate the efforts of many while multiplying
success over time. Until then, the language of others will continue to substitute
opinion for knowledge in the search for leadership of the built environment. The
goal is to prevent this artificial presence from consuming a natural gift that
constantly adjusts in reaction to a universe of forces. Our responsibility is
to recognize that cities are one of the forces to be reconciled, that the
shelter we build reflects the level of awareness we achieve, that shelter within limits
requires an improved understanding of the intensity and impact options involved,
and that symbiotic survival is the goal. Intuition is again required – and
leadership is needed when anticipation must substitute for proof.
