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Gross building area is a function of the land
available and the height permitted. Its mass combines
with parking and pavement to produce a level of intensity. Intensity is
determined by the percentage of project open space off-setting building mass and
pavement area. The efficiency of a gross building area plan determines the
population and activity that can be sheltered. When total gross building area is
contained within sustainable geographic limits, the inventory will become a shelter resource and part
of a symbiotic relationship we establish to protect our source of life. Building
intensity within these limits, and occupant intensity within each building, will
determine the quality of life provided.
The word “symbiotic” has several meanings. “Mutual
benefit” is the definition that relates to all of my essays. A symbiotic
parasite has a relationship of mutual benefit with a host that contributes to its
continued survival. Our relationship to the planet must become symbiotic to survive.
My work has been devoted to a vocabulary of
architectural intensity that can be measured and evaluated at existing
locations. It includes forecasting software based on templates that accept
vocabulary values and predict gross building area options with embedded equations. Option
implications can then be evaluated based on original intensity research. Evaluation
is needed because excessive intensity can be prompted by growing populations
and is a threat to their quality of life. In other words, excessive intensity may protect
our source of life but prolong a miserable quality of life that benefits a few.
“Gross building area” is a fundamental prediction or
measurement that contributes to the definition of development capacity, or it
is a given that begins a search for land with adequate capacity. It is a key measurement,
forecast, or stipulation that permits the evaluation of additional implications.
“Building capacity” is the gross building area that
can be constructed under the conditions noted in a design specification. Building
intensity BINT is a gross building area option divided by the project open
space present, planned, or provided. Development intensity DINT is the sum of a
gross building area and pavement option divided by the project open space present,
planned, or provided. This will be discussed in greater detail in a moment, but
it should be clear that gross building area is a significant element in both
equations.
The point is that gross building area is shelter
capacity. Intensity defines how it is introduced. It is not a
substitute for fine art. It is simply a foundation with
leadership potential, and it can be a cornerstone of credibility to help us pursue
architecture and city design in the public and private interest.
I have suggested in earlier essays that the goal is
to supplement land use allocation with intensity awareness to protect our
quality and source of life. This means that we must be able to define and
predict the intensity implications of architectural design specification decisions. It is why
I have focused on a language and vocabulary of intensity for use in development
capacity forecasting and evaluation.
The key to intensity prediction involves accurate gross building area forecasting. It also involves internal floor plan
arrangement that will be discussed under the heading “Building Efficiency”. Shelter
activity and intensity combines with the Movement, Open Space and Life Support
divisions of our built environment to determine the physical, social,
psychological and economic quality of life offered. A new level of instinctive
awareness is telling many that it must be contained within sustainable
geographic limits to protect its source of life.
We have not been able to measure or predict intensity
in a language that has leadership potential. It is a function of gross building
area, however; and gross building area options can be forecast from design
specification values. This means we can measure and predict the intensity
spectrum produced by specification combinations and evaluate their
implications.
This essay proposes two intensity scales. One
measures building intensity and the other, total development intensity. The
equation for building intensity is BINT = GBA / (BLA * S), but I have mentioned
in previous essays that GBA / BLA is a version of the floor area ratio FAR. It
substitutes buildable land area BLA for gross land area GLA, however; since the
two are not always equal in area and intensity is imposed on a population
within the buildable land area occupied, in my opinion. When FAR is equal to
GBA / BLA therefore; the definition of building intensity can be simplified to:
BINT = FAR * S
This is a measurement equation that ignores the
amount of parking and pavement introduced. Total development area TDA includes gross
building area GBA, parking area PCA, and miscellaneous pavement area MPA since
they all contribute to intensity. This would make the
floor area ratio FAR a development area ratio DAR equal to GBA+PCA+MPA. When
DAR is substituted for FAR in the preceding equation, the equation for
development intensity becomes:
DINT = DAR * S
These two measurements indicate the intensity of gross
building area planned, present or proposed. I’ve referred to them as blood
pressure readings without a frame of reference.
Measurement makes it possible to evaluate existing
conditions and establish a quality of life index for intensity, but quality of
life options depend on the ability to comprehensively forecast gross building
area alternatives. This has been, and often still is, a trial and error effort
that produces a limited number of options for evaluation within a reasonable
time frame.
I created Development
Capacity Evaluation software DCE to quickly forecast an infinite number of gross
building area GBA options based on the design specification values entered in one
of its design category templates. This unlocks the ability to calculate the
intensity created by each GBA and total development area TDA option forecast.
It also unlocks our ability to evaluate activity and shelter intensity options within
symbiotic geographic limits.
Table 1 is included at the end of this essay to
illustrate the calculation of building intensity BINT and development intensity
DINT when a gross building area objective is given and the buildable land area
is to be found. Project open space percentages vary in the left hand column of
the Planning Forecast table to create options.
Table 2 is included to illustrate the calculation
of BINT and DINT when a gross land area is given and gross building area options
GBA are to be found. The number of floors varies in the left hand column of the
Planning Forecast table to create options.
Please note that the DINT values are significantly
greater than the BINT values. DINT values indicate the total intensity present,
planned, or predicted for an urban fabric that must rely on its weave of open
space for relief.
Gross
Building Area Efficiency
Gross building area, pavement and project open
space combine to exert varying degrees of intensity on a surrounding area.
Projects combine to form neighborhoods, districts, cities and regions that are
collectively referred to as urban form, but open space is often in short supply.
Urban form has now grown into sprawl seeking relief from intensity and has
little concern for the source of life being consumed and polluted.
The external relationship of shelter to its
neighbors and environment is only part of the problem, however. When
populations are considered, the internal efficiency of gross building area
becomes a significant architectural issue, since population capacity and activity affects cost,
return on investment, public revenue and expense, traffic generation and so on is involved.
Gross building area is a raw material that can be
adapted to serve any land use category, but building efficiency BEF determines
the floor area available to serve a specific activity and population. If a
building is 85% efficient, 15% is devoted to wall thickness, vertical and
horizontal circulation, mechanical / electrical rooms and shafts, lobbies, rest
rooms and so on. I’ve called these support areas. In other words, net area is a
fraction of the gross building area and the percentage indicates the first category
of floor plan efficiency. Net efficiency can refer to either lease area or occupied
area, however. Lease area can include all building support areas except
exterior wall thickness. It is of primary interest to a landlord, since a pro-rated
share of support area is leased to every tenant. The definition of lease area
is contained in the leasing terms of a contract, however, and there is no
consistent definition to my knowledge.
Actual building efficiency is net area that excludes all shared building
support functions and areas. In other words, net building efficiency indicates
the realistic area for occupation. Occupant efficiency indicates the realistic
area available for personal activity. It is found by subtracting such things
as, but not limited to, private reception areas, hallways, utility closets,
private rest rooms, partition thicknesses, and columns from the net building
area. Occupant efficiency OEF can be substantially less than building efficiency BEF. In fact, if you
subject one of your plans to net and occupant efficiency measurements the
results may surprise you. Occupant efficiency can be less than 50% of gross
building area GBA for some activities. This is important because the objective
is to shelter shared and personal population activity without excessive
intensity within a limited occupant area.
Tables 1 and 2 are concerned with gross building area
GBA calculations and do not include building efficiency percentages. They are included to illustrate BINT and DINT calculations. Table 3 is
based on forecast model RG1L and pertains to residential apartment buildings
using grade parking around, but not under, the building(s). It includes a
building efficiency percentage (Be) in its design specification template
because it is a critical factor contributing to the number of dwelling units
that can be included within the gross building area GBA. The percentage entered
is the estimated net building area NBA that will remain.
When an apartment building efficiency percentage is
multiplied by a gross building area measurement or forecast, the result defines
the gross dwelling unit area remaining within the building. This is subdivided
into individual unit areas designated by the number of bedrooms provided. A
“mix” refers to the percentage of each unit type provided.
The Dwelling Unit Mix template in Table 3 calculates an aggregate
average dwelling unit area AGG from the building efficiency, mix and net dwelling
unit areas under consideration. The AGG value is used to forecast the number of
dwelling units that can be included within the gross building area. The
template begins with a column of potential dwelling unit types. The desired
gross dwelling unit area GDA for each dwelling unit type is located in the
adjacent column. A comprehensive dwelling unit area CDA is found by adding a
pro-rated portion of the building support area BSA. In the case of Table 3, CDA
= GDA / 85%. The MIX column identifies the percentage of each dwelling unity
type being considered. In this case, the mix is 30% one bedroom dwelling units
and 70% two bedroom dwelling units. When the MIX percentage is multiplied by
the comprehensive dwelling unit value CDA, a pro-rated dwelling unit area PDA
is found. The sum of these pro-rated areas is equal to an aggregate average
dwelling unit area AGG. This is a value equal to the gross building area
divided by the number of dwelling units provided.
When a gross building area is forecast from design
specification values and divided by a calculated AGG value, the result is a
prediction of dwelling unit capacity. This is the number of dwelling units NDU
that can be accommodated given the dwelling unit mix under consideration. Occupant
space within a gross dwelling unit area is further reduced by the wall
thicknesses of the floor plan.
The point is that everything begins with a forecast
of gross building area potential in relation to the buildable land area BLA
available, and this is a function of design specification values. The result is
building mass that imposes a level of intensity on its neighbors and a gross
building area that is further subdivided into net building area NBA and occupant area OCA. These
areas are a function of floor plan design efficiency. When they are divided by
the population POP introduced, a level of internal intensity is measured. This can be expressed as:
IINT = NBA / POP, or
IINT = OCA / POP
From my limited experience, net building area can
be 70% - 90% of gross building area and occupant area can be 70% - 90% of net
building area. This means that 49% - 81% of gross building area becomes focused
activity area. When population is added to net or focused activity area,
internal intensity is created.
The implications become more significant when a
limited, sustainable land area is considered. The development capacity of a
limited land area is determined by the relationship of building height, mass,
and pavement to project open space. Since buildings are not particularly
efficient in general, but absolutely essential elements of survival, intensity
will become a challenging issue for growing populations that seek to live
within sustainable geographic limits.
Summary
If the goal is to live within sustainable limits,
efficiency begins with the land use allocation of activity and gross building
area within these limits. The combination of activity and intensity not
only represents shelter capacity and profit but revenue and expense to both public and
private interests. We are all too familiar with the results produced when
activity and intensity relationships cannot support themselves over time within
jurisdictional boundaries. Blight is the name of miscalculation. This takes on
an added dimension of concern when environmental boundaries are considered.
The goal is to shelter the activities of growing
populations without threatening their source of life with sprawl, or their quality
of life with excessive intensity. This is only part of the problem, however. In
the end, architectural form must represent symbiotic function within
sustainable geographic limits.
Postscript
It has become traditional to measure intensity with
density and floor area ratios, but neither has been part of an accurate tool
set. This is why I submitted new intensity equations in “Replacing Density” and
“Replacing the Floor Area Ratio”. (They are part of a predictive series of
equations embedded in the forecast models of Development Capacity Evaluation v2 software. The software is
attached to its companion book / manual entitled, Land Development
Calculations, 2e, McGraw-Hill, 2009.)