NOTE: All tables,
exhibits and figures are placed at the end of this text.
A planning design specification can be used to lead shelter
capacity, intensity and context results within a Built Domain that must be geographically
limited to protect its source of life, The Natural Domain. This approach is not
based on the qualitative evaluation of form, function and appearance. It is
based on the measurement, evaluation, prediction and adoption of correlated
topic quantities that produce shelter capacity, intensity and context within a Built
Domain that must be limited to protect its source of life from sprawl.
A design specification template begins with a comprehensive
list of site planning topics related to a building design category. Values
assigned to these topics are mathematically correlated with an algorithm and
master equation to predict shelter capacity, intensity, and open space options
within a single project area. Single project definitions are then aggregated to
form neighborhood, district, city and regional context definitions.
A specification template within a forecast model is shown on
lines 3-34 of Table 1. It defines the project shown in Figure 1 and includes
land and building modules with topic lines that introduce assigned and
calculated values. A box is used to designate an assigned value. One or more of
these assigned values may be modified in a specification to evaluate the options
predicted in the Planning Forecast Panel shown on lines B42-E51. The floor
quantity values entered in cells A42-A51 of the panel are part of the design
specification and may also be modified to test optional decisions.
Table 1 pertains to the G1 building design category and
requires that the gross land area be given in cell F3. The G1 Design Category classification
pertains to all buildings that use surface parking around, but not under, the
building to serve occupant activity. (Exhibit A presents the complete building design
category list with its related forecast models.)
The percentage variables entered in the design specification
boxes of Table 1 are used to calculate land areas that are subtracted from the
gross land area given to arrive at the core land area remaining for gross
building footprint and parking lot area. This core area value is calculated in
cell G32 of Table 1.
As a parking lot expands to serve increased gross building
area within a fixed core area, building footprint area shrinks to make room and
floor quantity increases to accommodate the increased gross building area. This
relationship is defined by the master equation in cell A37. Parking lot design
variables are entered in cells F33 and F34 to satisfy two of the values
required by the equation. The last value required is floor quantity, and quantity
options (f) are entered in the boxes of cells A42-A51 to satisfy the equation.
Gross building area options are calculated in cells B42-B51 using the master
equation in cell A37. These options represent keystone data. When gross
building area options can be predicted in square feet, a wide array of related
project and planning implications can be calculated.
Exhibit B is a diagram of the site plan hierarchy that is
subtracted to find the core area remaining for building footprint and parking
lot area.
The design specification values in cells B42-G51 of Table 1
are correlated to produce project and planning forecast implications. These
predictions change when one or more design specification values are modified. The
forecast values presented in the Planning Forecast Panel of Table 1 are some of
the many that may be calculated and they fall into two categories. Cells
B42-E51 represent project design implications. Cells F42-G51 represent
corresponding planning implications.
The design specification in Table 2 defines the project
shown in Figure 2. The format of the specification is identical to Table 1, but
different specification values define the impact of Figure 2 and will be used
for comparison after an explanation of the following common characteristics.
This explanation uses Table 1 as a frame of reference.
PROJECT IMPLICATIONS
The gross building footprint predictions in Col. C of the Table
1 Planning Forecast Panel, and the gross parking lot predictions in Col. D, are
quantity predictions that combine to form the core area of a site plan. (Do not
confuse these quantities with a completed site plan illustration. The focus
here is on quantity prediction, not site plan arrangement. Quantity predictions
may be subdivided and separated in a final site plan arrangement, but their sum
must equal the category sum forecast.)
The increasing floor quantities in Col. A of the Planning
Forecast Panel produce corresponding increases in gross building are in Col. B.
These areas must be accommodated within the constant core area calculated in
cell G32 of the design specification. The increasing gross building areas are
served by the increasing surface parking areas calculated in Col. D. This means
that the building cover area in Col. C declines to make room for the increasing
parking lot area. Gross building area increases with increasing floor quantity
in Col. A, however. Increasing floor quantity multiplies the decreasing
building footprint area to produce larger gross building areas. I’ve previously
mentioned that this G1 design characteristic produces a steady decline in total
gross building area as floor quantity increases. Five floors is a realistic
limit for this building design category, even when design specification values
are modified to increase the core area available because the same decline curve
simply begins with a greater gross building area.
PLANNING IMPLICATIONS
The gross building area options in cells B42-B51 of Tables 1
and 2 are converted to a common, comparable index called shelter capacity in
cells F42-F51.
Shelter Capacity
(SFAC)
Shelter capacity is equal to gross building area divided by
the buildable acres consumed. The equation is noted in cell F41 of Table 1. Buildable
land area (BLA) is calculated in cell G10. Shelter capacity is a comparable
statistic that can be used to improve land use planning and economic
development decisions within limited geographic areas. These limitations will
become essential when we realize that the life-sustaining Natural Domain must
be protected from sprawling consumption by The Built Domain.
Keep in mind that gross building area can be occupied by any
activity, assuming building code compliance. Gross building area combines with
occupant activity to produce public revenue per acre and private return on
investment per building square foot. I’ll use the generic term “yield” to
indicate these financial implications. Average yield per acre and per square
foot must exceed average expense to ensure both public and private prosperity. In
other words, shelter capacity per acre combines with activity to produce average
yield per acre. When a city summarizes yield from all of its acres, the average
revenue must meet or exceed its average expense per acre to avoid budget
reductions. This means that we must recognize the importance of every acre on
the planet and improve our methods of shelter capacity prediction, correlation
and limitation in the search for a sustainable, symbiotic future.
Intensity (INT)
We intuitively know that excessive gross building area and
parking can overwhelm a neighborhood with building height, mass, pavement,
movement, and activity; but have not had an adequate method of measuring,
evaluating, and predicting this presence. If we can’t measure, we can’t
determine when the measurements represent excess. The secondary equation in
cell G41 of the Planning Forecast Panel has been provided to measure the
intensity implications of the shelter capacity options calculated in Col. F.
Keep in mind that a shelter capacity statistic in Col. F represents the
combined impact of all design specification values entered, and will change
when one or more of these values are modified.
The intensity results produced in cells G42-G51 calibrate
intensity without passing judgment. At the present time they simply sit within
the parameters of an intensity yardstick. The entire yardstick is presented in Table
5 and referred to as the Theory of Relative Shelter Intensity.
Table 5 is a complete departure from Table 1.2 presented on
page 16 of The Science of City Design. (Hosack, Walter M., CreateSpace,
317 pgs., 2016. Page 16, and the related tables on pages 166 and 188, should
now be considered outdated.) The change to the intensity, intrusion and
dominance calculations on page 16 was prompted as I prepared comparative Tables
3 and 4 in this essay. The initial calculations made with the older algorithm
produced conflicting comparisons in this essay that revealed a logical error. I
have simplified the equation and improved its logic by discarding the concepts
of intrusion and dominance that are already reflected by shelter capacity
calculations. The result is Table 5. It is a simple yardstick that indexes the
results produced by a correlated set of design specification values. This makes
comparison and evaluation of design specification results feasible. Knowledge
quickly follows the ability to measure and evaluate.
Summary
Tables 1 and 2 are represented a building design category
chosen from Exhibit A for evaluation of a given land area. Core area was
distilled from gross land area by subtracting the percentage values assigned to
a series of site plan topics in a design specification template. Gross building
area options were predicted with a master equation after additional parking and
floor quantity values were entered in the G1 Module of the specification. Gross
building area predictions were divided by the constant buildable acres calculated
to produce shelter capacity measurements per acre. These measurements could be
compared to those from other projects. These calculations were converted to
their intensity equivalents using the secondary equation in cell G41 of Tables
1 and 2.
The intensity measurements presented in cells G42-G51 are
similar to early blood pressure measurements. The measurements were meaningless
until a database of comparable measurements with related evaluation was
compiled. When shelter capacity and intensity calculations follow the same
path, the result will be a credible bridge language that can defend intuition,
talent, opinion and experience. The language will represent a scientific method
for accumulating city design knowledge that can also be taught without
excessive reliance on intangible artistic intuition and talent.
EVALUATION of COMPARABLE
MEASUREMENTS
Table 1 presented a design specification template containing
values related to Figure 1. Table 2 presented the same template with values
related to Figure 2. These comparative measurements make evaluation on a
quantitative basis feasible. This separates opinion regarding building form,
appearance, and beauty from design specifications that determine shelter capacity,
intensity and context within the Shelter Division of The Built Domain. In other
words, a recipe precedes a cake but is not a substitute for successful
execution and pleasing appearance.
Recipes apply to every shelter cell we define with property
lines, but the ingredients and quantities of cellular matter have not been
comprehensively listed and consistently measured to evaluate their impact on
the urban and rural context we inhabit. We have spent more time with
microscopes than with telescopes that observe this growing organism from space,
and have been distracted by appearance. This has permitted these cells to
multiply in random carcinogenic patterns we call sprawl.
OPINION
Cellular recipes have been referred to as planning design
specifications in this essay. Existing undocumented cellular specifications can
be measured and evaluated to build knowledge regarding their implications. The cellular
project knowledge acquired will have consistent leadership potential when it is
combined to create plans for the space, mass, pavement and intensity characteristics
of shelter within neighborhoods, districts, cities and regions. This will
permit the design of contained cities composed of living cells that are
economically correlated within limited geographic areas to protect their source
of life.
There is no mystery to site plan quantity decisions. They
simply require research to improve knowledge and gain credibility that will
stimulate fine art within a shelter sanctuary served by movement, open space
and life support that constantly reminds us of the gift we have been given and
the obligation implied.
COMPARISON
The design specifications and forecast panels of Tables 1
and 2 represent the appearances presented in Figures 1 and 2. The Planning
Forecast Panels in Tables 3 and 4 are repeated from Tables 1 and 2 to reduce
the statistics presented. The statistics in cells A4 and G11 of Table 3, and
the statistics in cells A28 and G38 of Table 4 have been placed within Table 6.
Table 3 shows that the appearance of Figure 1 is represented
by a shelter capacity of 9,288 sq. ft. per acre in cell F11 and impervious
cover of 67.5% in cell A4. The intersection of these two values in Table 6
reveals an intensity measurement of 0.627. This is the same measurement calculated
in cell G11 of Table 3 and cell G42 of Table 1.
Table 4 shows that the appearance of Figure 2 is represented
by a shelter capacity of 6,935 sq. ft. per acre in cell F38 and impervious
cover of 19.0% in cell A28. The intersection of these two values in Table 6
reveals an intensity measurement of 0.132. This is the same measurement calculated
in cell G38 of Table 3 and in cell G45 of Table 2.
As a frame of reference, many single family residential subdivisions
are designed with a storm sewer capacity equal to 30% impervious cover. This
reduces initial infrastructure cost but limits future expansion potential. If
one buildable acre contains 5,000 sq. ft. of total gross building area, and is
limited by a storm sewer capacity of 30%, the intersection of these two values
in Table 6 reveals a maximum intensity measurement of 0.150.
The Figure 1 intensity of 0.627 is well above the low
density residential intensity of 0.150. The Figure 2 intensity of 0.132 is lower
than this suburban intensity. The context impression left by Figure 2 is often referred
to as an “office park”.
When I visually compare the parking, pavement, open space
and building mass of Figure 1 to Figure 2 without evaluating building form and
appearance, I prefer Figure 2. It has 25% less shelter capacity per acre however,
and the capacities are not further apart because Figure 2 is a four story building.
In other words, more land is used to produce shelter in Figure 2, and land is a
finite resource that is our source of life. It is not a commodity that can be
owned, consumed, polluted and discarded without consequences.
If you prefer Figure 2, it means that more land must be used
to shelter activity within a geographic area. If geographic limits are accepted
to protect our source of life from sprawl, population growth and its activities
will require city design decisions that balance shelter intensity and context within
these limits. These are inescapable relationships. Tables 1 and 2 are simply tools
that make credible evaluation feasible.
Building capacity, intensity and context shelters the many activities
of growing populations. I have raised the issue to alert you that this is now a
finite planet. It is no longer a world without end that can shelter unending
growth, and we have a responsibility to plan accordingly. I have given you a
tool set in my book, The Science of City Design. It can be used to
evaluate options because shelter is currently expanding to consume our source
of life. The disease is called sprawl. When inspecting sprawl from a satellite,
we need to look no further than the inhabitants of shelter to find the active cause
of this disease on the face of the planet. The words growth, success, progress,
capacity, intensity and context take on new meaning from this perspective.
Copyright. Walter M. Hosack, 2017. All Rights Reserved.
