THE BUILT DOMAIN
In the Built Domain, open space is either paved or unpaved
and used to serve either pedestrian, vehicular, or infrastructure activity. For
instance, plazas, squares, sidewalks, and miscellaneous pavement serve
pedestrian activity. Parking lots, parking structures, and right-of-way
pavement serve vehicular activity. Utility easements serve life support systems.
All provide access to light, air, and ventilation by separating building mass
and height, but the similarity ends with the degree of intensity introduced.
Parking lots have been a dilemma. They provide access to
light, air, and ventilation but do not separate the pedestrian from vehicular
mass and movement that combines with building mass and height to create
increased physical intensity. They have often been justified in the yard areas of
non-residential areas on this basis. Justification occurs because pedestrian
open space decreases the core area of a parcel that is available for parking
and building cover.
In other words, pedestrian open space allocation decreases
the gross building area potential of a parcel. This potential can only be
recovered with increased floor quantity until the horizontal expansion of
parking reduces the core area remaining for a building footprint that can be
multiplied by increased floor quantity.
Vehicular open space abounds. The challenge is to provide
open space for pedestrian benefit woven over many parcels without excessively
compromising the shelter capacity and economic potential of land. It is an
urban design challenge that can only be met with improved mathematical
evaluation.
The shelter capacity and activity placed on land determines
its economic value to both public and private interests. Then considering the
G1 Building Design Category in particular, the private sector temptation is to
maximize shelter capacity by eliminating pedestrian open space while increasing
parking and floor quantity to increase intensity that often degrades context. The
public sector challenge is to mathematically define its physical, social, and
economic objectives with urban design mathematics and form that balances the
economic yield from shelter capacity and activity with the pedestrian open
spaces needed to encourage a desirable quality of life in a limited Built
Domain.
SHELTER CAPACITY EVALUATION
I’ve used Table 1 to explain shelter capacity evaluation, or
Tegimenics, on many occasions for the G1 Building Design Category. I’m
including it here to explain what I mean by the term “mathematical evaluation of
shelter capacity” based on the G1.L1 Building Design Category. This category applies
to all buildings with a surface parking lot around but not under the building
on the same premise, excluding land area reserved for future expansion. This
category applies when gross land area is given and gross building area options
for the land given are to be found.
The Land Module in Table 1 begins with the gross land area
given in cell F3. The remaining gray cells in the module identify percentage
quantities measured or estimated that must be subtracted from the gross land
area given to find what is called “shelter area remaining” in cell F17. This land
is reduced by site limitations that continue to be reduced by the land area
percentage estimates entered in the gray cells of the Core Module. These
reductions produce the core land area remaining in cell F33 for building cover
and parking lot cover.
The optional values entered in gray cells A35 and A36 of the
Core Module identify the grade parking requirements involved. The values
entered in gray cells A44-A53 represent the floor quantities under
consideration.
The master equation in cell B39 is used to predict the gross
building area options calculated in Col. B44-B53. These options rapidly decline
as floor quantity increases because building cover in Col. C44-C53 declines as
parking lot areas increases in Col. D44-D53. The result is declining building cover
area potential per floor. When increasing floor quantity is multiplied by declining
building cover area per floor in a
limited core area, the result is a declining increase in gross building area
potential per floor.
This is a unique characteristic
of the G1 Building Design Category. It indicates that any floor quantity
greater than 5 produces rapidly declining gross building area potential in
return for the expense encountered. I have strayed from the point of this essay
in this paragraph, and have made this point in the past, but couldn’t resist
reemphasizing the observation.
The shelter capacity, intensity, intrusion, and context
implications of the gross building area options in Col. A44-A53 are measured in
the Implications Module of F44-J53 using the master equations in row F44-J44. However,
these measurements will have little meaning until many existing conditions are measured,
compared ,and evaluated to build a library of reference knowledge that I’ve
christened Tegimenology.
Returning to the point, the master equation in cell B39
shows that the core area found in cell G33 yields gross building area potential
for the G1 Building Design Category in cells B44-B53 when multiplied by the
coefficient (af) / (a + (fs)). The core area of any parcel can vary widely
based on the values entered in the gray cells of the Land and Core Modules in
Table 1, but I am singling out the unpaved open space value entered in cell F11
because it is a pivotal, and often ignored, factor in site planning design that
diminishes the gross building area potential, shelter capacity, and
profitability of land. It combines with miscellaneous pavement such as plazas
and terraces however, to reduce the pedestrian intensity introduced by building
mass, parking, pavement, and vehicular movement.
Adequate pedestrian open space throughout a city remains a
contentious urban design issue as well as a project planning issue because
urban economics is involved. The same is true for vehicular parking. Both
affect the profitability of land; its revenue potential; and its contribution
to a city’s quality of life; but neither has come close to a consensus over the
quantity objectives that need to be pursued because comprehensive mathematical
evaluation has not been feasible.
Table 1 shows that the 30% unpaved open space provision in
cell F11 and the grade parking requirements in cells A35 and A36 have
contributed to a five-story gross building area forecast of 28,264 sq. ft., a
shelter capacity of 16,262 sq. ft. per buildable acre, an intensity of 1.138,
an intrusion of 1.0, and a context reading of 2.138. The intensity, intrusion,
and context readings, however, are like our first blood pressure readings. They
have little meaning without comparison to additional existing measurements and
evaluations.
The shelter capacity prediction of 16,262 sq. ft. per
buildable acre has greater immediate use. If the intended occupant activity has
a revenue potential of $1.00 per sq. ft., the project has a revenue potential
of $16,262 per buildable acre. Comparing this to a city’s total average annual
expense per taxable acre would indicate the project’s ability to contribute to
a balanced budget, and its value to an economic development plan.
Table 2 illustrates what happens when the unpaved open space
value in cell F11 of Table 1 is increased to 40% and all other values remain constant.
In this case the core area in cell F33 declines to 43,607 sq. ft. and the
5-floor gross building area prediction declines from 28,264 sq. ft. to 24,226
sq. ft. Shelter capacity in cell F48
declines to 13,939 sq. ft. per buildable acre and projected revenue would
decline to $13,939 per buildable acre from $16,262.
Table 3 illustrates what happens when the parking
requirement (a) in cell A36 is increased to 300 square feet of building area permitted
per parking space from 250 and all other values from Table 2 remain constant.
In this case the core area remains 43,607 sq. ft. and the 5-floor gross
building area prediction increases to 28,264 sq. ft. Shelter capacity in cell
F48 increases to 16,263 sq. ft. per buildable acre and projected annual revenue
increases to $16,263 per buildable acre from $16,262.
This exercise is intended to show a few of the trade-offs
involved when mathematical shelter capacity evaluation, or Tegimenics is used
to evaluate urban design decisions and economic development opportunities. It
has illustrated the impact of open space, parking, and floor quantity
decisions. These are just few of those represented by the values entered in the
gray cells of Tables 1, 2, and 3. I have singled them out to ask a question. Is
pedestrian open space woven throughout a city a priority? It reduces shelter
capacity and parking potential unless other building design categories and
floor quantities are introduced. But does the concept of a public right to “welfare”
mean “quality of life”, and can it be defined by evaluating the implications of
shelter capacity, intensity, intrusion, and context measurements, predictions,
and leadership decisions?
CONCLUSION
A change to any one or more of the gray cell decisions in
Tables 1, 2, and 3 would change the gross building area range of possibilities
and their implications. In fact, the implications presented are just a few of
the many that can be predicted from a building design category forecast model,
and the possibilities expand when all six building design categories are
considered.
GLOSSARY
Built Domain: Land used for the Shelter,
Movement, Open Space, and Life Support Divisions in a city’s Urban and Rural
Phyla.
Urban Phyla: Land
devoted to shelter, movement, open space, and life support in areas not devoted
to agriculture.
Rural Phyla: Land
devoted to shelter, movement, open space, and life support in areas devoted to
agriculture.
Natural Domain: The planet’s surface remaining
after the Built Domain is subtracted.
Project Core Area: The
site plan area remaining for building cover and parking cover after all other
quantity requirements are subtracted. (CORE = BCA + PCA)
Project Shelter Capacity: The
gross building area present or planned divided by the buildable acres occupied,
excluding future expansion area. (SFAC = GBA / BAC)
Project Intensity: Project
shelter capacity times the impervious percentage present divided by 10,000.
(INT = (SFAC * IMP% / 10,000))
Project Intrusion: The
floor quantity present or planned divided by 5. (INTR = f / 5)
Project Context: Intensity
plus Intrusion. (CTX = INT + INTR)
Project Revenue per Acre: Revenue
present or planned per gross building square foot times the shelter capacity
per buildable acre. (REVAC = REVSF * SFAC)
BUILDING DESIGN CATEGORY CLASSIFICATION
(G1) All buildings served by a
surface parking lot around, but not under, the building, excluding land
reserved for future expansion.
(G2) All buildings served by surface
parking around and/or under the building, excluding land reserved for future
expansion.
(S1) All buildings served by
adjacent parking garage levels, spaces, and auxiliary surface parking that
consume a portion of the core land area available on the same premise.
(S2) All buildings and auxiliary
surface parking served by an underground parking garage within the buildable
land area of the premise.
(S3) All buildings and auxiliary
surface parking served by a parking garage below the building within the core
land area available on the same premise
(NP) All buildings not served by
surface or structure parking on the same premise.
FURTHER INFORMATION
Further information about the building design categories,
design specification topics, prediction panels, and implication modules of
shelter capacity forecast models, can be found in my book, “The Equations of
Urban Design”, using the following url:
https://www.amazon.com/-/e/B001IR3ODO?ref_=pe_584750_33951330
You may also be interested in some of the 285 essays on my
blog at www.wmhosack.blogspot.com.
They address topics related to the use of shelter capacity evaluation forecast
models and their implication measurement modules.
Walter M. Hosack, July 2026
