Thursday, September 30, 2010

REPLACING DENSITY

PLEASE NOTE THAT MY PRIMARY SITE IS NOW LOCATED AT “THE BUILT DOMAIN.NET”. A link is provided in the upper right hand corner of the screen.


Density is not equal to the leadership required because it is an imperfect and unreliable measurement of intensity. It must be replaced with a yardstick that can more accurately measure cause and predict effect.

The development capacity of land is equal to the gross building area that can be constructed per acre available. Gross building area however, is simply a volume that provides shelter on the floors involved. The amount provided per acre, in addition to the supporting pavement introduced, is referred to as “intensity” when compared to the project open space that remains. At one end of the 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 a measure of the physical intensity introduced.

When gross building area is planned or converted for a specific activity, such as a hospital, the physical level of intensity is also affected by the social activity planned. The combination is referred to as “land use”, and its condition is affected by its economic stability and social acceptance. In other words, the land development capacity utilized produces levels of physical intensity, social activity, and economic contribution that affect our quality of life within the built environment.  

The movement and life support divisions of our built environment open up land for development, but intensity begins with the square feet of building area and pavement provided per acre of land consumed -- in relation to the project open space that remains. This determines the population that can be served, the scope of activity that can be conducted, the economic contribution that can be expected, and the quality of life encouraged. It also determines the extent of encroachment into a natural environment that must be preserved. In other words, the physical, social, and economic characteristics of intensity not only affect the health, safety, and welfare of a population within the built environment; but the survival of its natural partner beyond.

Density is a concept in the world of land use planning that is a statistic of performance, but an inadequate leadership metric. There are just too many loose ends that encourage random results because it does not anticipate the design categories, specification variables and mathematical relationships involved. Random intensity is one of these random results. It cannot be controlled by a simple density statistic because it is a function of the relationship between building mass, development cover and project open space on a given land area. Density can report results, but it cannot lead performance because it omits the pressure points of design. This is significant because we must learn to live within limits that do not threaten our quality of life -- while preserving the capacity of our natural environment to sustain it. Density cannot lead us there -- but intensity can.

            Physical intensity has three components: building mass, development cover, and project open space. Development cover is a generic name for pavement of various types, such as parking lots and plazas. Project open space excludes unbuildable areas such as ravines and is the amount of unpaved space within the buildable area of any property. Building mass is gross building area that is a function of the building height and floor plan involved. The floor plan area can be included with development cover to express the amount of impervious cover present, but this two-dimensional statistic defines balance. It does not define the intensity created by the relationship of three-dimensional form and pavement to open space. This relationship can be defined with equations that relate to design categories and operate with values assigned to their design specification variables. These variables have been considered separately throughout history, but are actually elements within equations that can be written to predict the intensity, or gross building area per acre, that a design category will produce under the conditions specified by the values entered.  

For example, CG1 identifies a non-residential design category using a parking lot around, but not under the building. CG1L indicates that the gross land area must be known to use the equation involved. In this case, the optimum relationship between parking cover, PCA, and building cover, BCA, within the core area, CORE, determines the gross building area GBA that can be produced; and is a function of the core mass divided by a capacity coefficient. The core mass is simply a function of the core area available (CORE) multiplied by the number of building floors (f) contemplated. The capacity coefficient is a function of the building floors (f) and parking lot specifications involved (s and a). The gross building area GBA that can be achieved by a CG1 design category is defined by the following relationship between core mass and the CG1 capacity coefficient.


s = a value representing the average gross parking lot area, including landscaped islands, divided by the number of parking spaces provided  (different values represent different parking lot designs)
a = the maximum building area permitted per parking space provided


Physical intensity for all design categories is equal to the gross building area forecast in sq ft divided by the acres under study. This can be expressed with the following equation.


I = GBA / AC


I = intensity expressed in terms of gross building area sq ft per acre
GBA = gross building area in sq ft
AC = gross land area, GLA: or net land area, NLA; or buildable land area BLA; or core land area CORE in acres



The key to the GBA equation is the concept of “core area”. This is the area that remains for building cover and parking cover after percentages are subtracted for project open space, unbuildable areas, rights-of-way and other required set-asides. The equation defines the gross building area GBA that will be produced within the core area based on the specification values entered. Additional options are produced by changing values or design categories, and hundreds can be produced in the time it would take to sketch one.

Intensity choices 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 this step however, the intensity product is referred to as a massing composition. 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 environment. Intensity equations make it possible to measure, evaluate, diagnose, and prescribe urban form one project at a time. When a built environment is 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 CG1L equation reveals a design principle that can be formally expressed in the following terms:

When a CG1 design concept is considered, the rate of increase in development capacity 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 development capacity as building height pushes above five floors. It is a very popular suburban design concept but an inefficient use of the land. If a larger building on the same land area were desired, based on the same design concept; a larger core area would be required. The increase however, would come at the expense of open space, and/or parking spaces within the core area. Figure 1 is based on the provision of 30% 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 the implications remain a matter of opinion.



            Figure 1 confirms the intuition of many designers and converts this intuition to knowledge that is a function of the CG1L 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 development capacity of this land, is becoming an issue of survival. The answers we find will again be reflected in the architecture of our solutions, and extend to the context we create with the four divisions of our built environment.

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 the population included with the average intensity required. This is an emerging awareness tormented by conflicting opinion; but fortunately, intensity can be predicted. The options forecast however, have context implications that remain to be explored; and research is required to avoid the oppression intensity 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 restraint demanded by its silent partner -- and to the quality of life deserved by its inhabitants.

The built environment contains four divisions, and the shelter division is served by the movement, open space, and life support divisions. The capacity of land to accommodate shelter is based on the design category involved and the specification values chosen. These choices have been arbitrary and evaluation has been limited by the time required to predict alternatives. A better system is needed, since we cannot restrain our tendency to consume the face of this planet until we can quickly and accurately predict options in a language that can lead the work of many over time -- and expand over generations.

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 intensity 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 achieved, and that shelter within limits requires an improved understanding of the intensity options involved.

Struggles for freedom establish new relationships among men, but over-simplify their relationship to a planet within a universe that is a gift from infinity. We may be free to own the land, sea and air, but we are not free to abuse it and its inhabitants in the silent court that prevails. Our knowledge is limited, our vocabulary is inadequate, and our language is ineffective; but our vision must restrain an instinct to control or be dominated that has become a threat to the planet. It is time to follow the road from intuition to science again; and many sciences must collaborate to lead the shape, form, and intensity of cities toward the harmony needed. Density is not equal to the leadership required because it is an imperfect and unreliable measurement of intensity. It must be replaced with a yardstick that can more accurately measure cause and predict effect in order to convince others of the direction needed and the decisions required. Nothing less than symbiotic adaptation is involved, and we must again prove that we are equal to the threat success has produced by providing the leadership required.

Agenda

For the leaders among us, I’d like to suggest the following preliminary agenda, since the language of intensity is simply a method of expressing decisions regarding the shelter division of our built environment. The leadership topic before us is our relationship to the balance required for survival, and the following are significant objectives.

  1. Balance the natural / artificial equation.
    1. Action: Evaluate the geographic areas, atmospheric content and fundamental resources that must be preserved to sustain all species of life on Earth.
    2. Reason: To identify the land remaining for the activities of our built environment
  2. Balance the urban / rural equation.
    1. Action: Evaluate the agricultural potential of land within the built environment
    2. Reason: To balance food supply and shelter supply within the limits of this environment
  3. Balance the intensity / open space equation
    1. Action: Evaluate the urban intensity and quality of life options implied by rural land allocation options within a limited built environment area
    2. Reason: Development capacity is a function of intensity, and excessive intensity produces an inferior quality of life. Intensity is a function of the relationship between building mass, development cover and project open space; and inversely proportional to the amount of open space provided. At one end of the intensity spectrum is a home on hundreds of acres. At the other is a high-rise tenement crowded among others and filled with disease, despair, and insecurity. We have found that simply adding open space does not solve the problem, but have yet to define the physical relationships that reflect social and economic stability within this artificial world.
  4. Balance the land use / economic stability equation
    1. Action: Evaluate the public income potential from land use activity and intensity
    2. Reason: Land use allocation areas produce economic yield based on the activities and intensities involved. A successful allocation plan that includes intensity objectives will produce an average yield and accumulated reserve that meets expense and permits capital improvement over time.
  5. Balance the ownership / planning equation
a.       Action: Evaluate methods of adjusting property ownership concepts to the natural demands of the planet and the economic demands of our financial system
b.       Reason: Natural forces have property rights that cannot be seized during our battles with each other. Land ownership is an embedded survival instinct. It tells us to control the land or be controlled by others, and it assumes that control permits use; but agriculture has taught us that use requires restraint to preserve potential. A city is like a farm in many ways. When we consume the potential of land to support life we reduce our chances of survival. This means there is no link between ownership and use because natural demands prevail. We simply do not understand them and often respond with ignorance. Revising our priorities is a challenge to ownership that requires an adequate form of compensation, but there is no greater public interest than the symbiotic relationship we must establish with a planet that endures our presence at its discretion.
6.   Balance the human activity / natural activity equation
a.       Action: Evaluate the human activities that are expected to function in a symbiotic relationship with the planet and modify them as required
b.       Reason: To preserve the gift that has become our responsibility. The devil is certainly in the detail -- and we must confront him again in a battle with ourselves.

Conclusion

Intuition and science are alerting us to the environmental consequences of architecture, landscape architecture, city planning, and regional development, but proof remains a matter of opinion. Activities that consume the land alter its function and disturb the natural order; but the proof of extinction will make the hypothesis irrelevant, so intuition is again required for survival -- and leadership is required when anticipation must substitute for proof.

See also, "Replacing the Floor Area Ratio"

Author Note: Portions of this article were excerpted and edited from the second edition of my book, Land Development Calculations, and its attached forecasting software, Development Capacity Evaluation, v2.0 published by The McGraw-Hill Companies, 2010. The book can be found on Amazon.com.

No comments:

Post a Comment