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Wednesday, August 16, 2023

A Glimpse Into the Shelter Capacity Spectrum

 

The public right to protect its health, safety, and welfare from inadequate property owner provisions of light, air, ventilation, sanitation, hygiene, fire safety, dwelling area and so on brought us planning, zoning, and building regulation at the beginning of the 20th century. This was followed by building codes; master plans that anticipated unlimited annexation; and zoning codes that did not correlate independent regulations concerning density, parking, building height, yard setbacks, and so on. These independent zoning requirements couldn’t avoid contradiction because they lacked the mathematical correlation that can only be provided by architectural algorithms or the mind of a qualified and talented designer. There is no substitute for the creative ability to produce uniquely successful projects, but a mathematically correlated leadership foundation can be created as a substitute for the random regulation that addresses isolated topics of architectural design without calculating their combined implications, including excessive intensity within a sprawling urban fabric.

You will read about the potential to define mathematically correlated platforms for shelter design leadership by all related city design professions. It will involve terms like building design category, forecast model, design specification template, buildable land area, impervious cover, unpaved open space, shelter area, core area, parking specification, floor quantity, gross building area, building footprint, and the shelter capacity, intensity, intrusion, and dominance implications of correlated design specification decisions. I hope these terms are not new to you since I’ve written about them often in the past. If they are, I think you will understand as you read. They will introduce you to the spectrum of development capacity options that will determine your ability to define and shelter the activities of growing populations within the composition of a limited Built Domain that is needed to protect our quality and source of life – the Natural Domain.

The Baseline

The maximum gross building area (GBA) potential of a given land area will be the baseline for this discussion. I’m going to use the forecast model G1.L1 in Table 1, and its master equation in cell B39, to establish this baseline and address the potential I’ve mentioned with something more than intuition and experience. I’ve discussed this table many times and have included the derivation of its master equation in my book, The Equations of Urban Design. The table addresses the (G1) Building Design Category when gross land area (L1) is given in cell F3. As a reminder, the G1 category includes all buildings served by a grade parking lot around, but not under, the building on the same premise. (A building design category may be occupied by any occupant activity more commonly referred to as a “land use”. The emphasis here is not on the compatibility of adjacent land use activity, but on the shelter capacity of a given land area. Capacity and condition encourages or discourages activity. Shelter capacity, condition, and location deficiencies discourage economic development.)

The workhorse for this discussion is Table1. It will be used to create Tables 2 and 3. The parking assumptions in Table 1 have been entered in cells A35 and A36. Floor quantity options have been entered in cells A49-A53; and an assumed gross land area has been entered in cell F3. The remaining shaded cell variables have been entered as zero to find the maximum development capacity of the land area given the parking specifications entered. The result is a prediction of gross building area potential (GBA) in cells B44-B53 for each of the floor quantity options entered in cells A44-A53. All of these forecasts are related to the land area given in cell F3. The predictions represent the maximum gross building area potential of the land area given when the project area is covered by parking lot and building footprint when the unpaved open space allocation in cell F11 is zero. This is an extreme condition but establishes one end of the potential development capacity spectrum for this building design category, land area, and parking specification.

A Unique G1 Characteristic

Before I go further, I’d like to point out why I’ve drawn a line under floor quantity 5 in Tables 1, 2 and 3. The line emphasizes a unique characteristic of the G1.L1 Building Design Category. I’ve mentioned this before so I ask previous readers to excuse the repetition.

When the value entered in cell A35 of Table 1 exceeds the value entered in cell A36, the surface parking lot will expand at a greater rate than the building footprint. Parking quantity and area must expand to justify increases in gross building area produced by increased floor quantities as the building footprint area declines. This parking lot expansion eventually shrinks the remaining building footprint area below a useful floor plan area.

The gross building area (GBA) increase per floor is calculated in cells B44-B53 of Table 1 based on the values entered for (s) and (a) in cells A35 and A36 of its Design Specification Template. These GBA values are repeated in Column B of Table 2. The increase per floor becomes negligible above 5 because of the relationship just mentioned. The line added below the 5 floor mark emphasizes this characteristic. The request for parking variances begins when the futility of increased floor quantity is recognized. Parking variances increase gross building area potential because they reduce the parking lot area required and expand the potential building footprint area. They also increase intensity that has been unmeasurable in the past. The variances, however, do not affect the 5 floor characteristic just mentioned.

The (GBA) predictions made in cells B44-B53 of Table 1 represent the maximum (GBA) potential of the land area given the values entered in the Design Specification Template of Table 1. A change to one or more of these values would produce a new forecast.

Shelter Capacity

I also need to introduce the concept of shelter capacity as a prerequisite to the remainder of this discussion. Gross building area calculations do not indicate the land area consumed. I have created shelter capacity calculations for this reason. The shelter capacity of a given buildable land area is equal to the gross building area square feet planned or present divided by the buildable land area involved in acres. The resulting dividend is shelter capacity per acre (SFAC). The calculation makes all building projects mathematically comparable to the land consumed and has the added benefit of enabling calculation of the intensity, intrusion, and dominance implied by the physical presence measured.

Shelter capacity (SFAC) is calculated in cells F44-F53 of Table 1 based on the equation in cell F43; the gross building area values calculated in cells B44-B53; and the buildable land area calculated in cell G10. In this example, the shelter capacity calculations represent the maximum development capacity of the 1.738 acre land area given based on the design specification values and floor quantity options entered in Table 1.  

The relationship between land, building, pavement, and open space will demand increasing attention as populations continue to expand and we come to realize that land preservation beyond our Built Domain is a mandate and not a choice.

Column B4-B13 in Table 2 repeats the shelter capacity values calculated in cells F44-F53 of Table 1. The remaining columns reflect the changes that occur when the zero unpaved open space value in cell F11 of Table 1 is replaced by the values in cells B3-M3 of Table 2. Each column in Table 2 calculates the shelter capacity produced in Table 1 for the floor quantity options entered in cells A4-A13 when the unpaved open space percentage is amended to equal the constant at the top of each column in Table 2.

Reading across rows 4-13 in Table 2 defines the shelter capacity reductions that occur when the unpaved open space percentage increases in row 3.

When all design specification values remain constant in the G1.L1 forecast model (except for the unpaved open space percentage in cell F11), Table 2 shows that: (1) increasing the unpaved open space percentage (S) required on the buildable land area (BLA) of a project will reduce the gross building area (GBA) potential of the area, and (2) an increased floor quantity (f) cannot recover a GBA loss when a significantly greater unpaved open space percentage (S) is required.

The entire range of shelter capacity implications associated with the unpaved open space increases in cells B3-L3 are shown in the columns of Table 2.The intensity implications of the increased unpaved open space allocations in Table 2 are recorded in Table 3. Both of these tables have been created from Table 1 by modifying the unpaved open space percentage in cell F11 of Table 1 to equal each of the percentages in Row 3 of Table 2 and Row 23 of Table 3.

Intensity

Physical intensity is a condition we feel but haven’t been able to measure. I doubt, however, that many will disagree that it has an effect on those adjacent to, or surrounded by, its presence. In fact, I believe that physical intensity has at the very least a social, psychological, environmental, and economic impact. This is why I created the Implication Module in Table 1. It measures intensity in relation to the building design categories and design specification decisions that determine its scope.

The Implications Module in Table 1 is based on the gross building area (GBA) predictions in cells B44-B53. It first measures shelter capacity (SFAC) in Column F for each of its GBA predictions. It then measures the intensity (INT), intrusion (INTR), and dominance (DOM) implied by the shelter capacity calculations in its succeeding columns using the equations in cells F43, G43, H43, and J43.

Table 3 records the intensity created per floor when the open space in Row 23 increases to mirror the increases in Row 3 of Table 2. As expected, intensity declines with the increasing percentage of unpaved open space provided per floor and increases within each open space category as floor quantity increases.

Tables 2 and 3 calculate the capacity and intensity options related to the design specifications entered in Table 1. The additional options that could be produced are not hard to imagine when you realize that there are 26 shaded design specification locations in Table 1, and that Tables 2 and 3 will change whenever one or more of these shaded values is modified.

It is inevitable that shelter design decisions become a guessing game with sprawl and excessive intensity as potential outcomes when the palette of design specification decisions is not understood mathematically correlated and intensity targets are not defined with knowledge based on pre-existing research.

Choice

Table 1 uses extreme design specification choices to define one end of the development capacity spectrum when parking value (s) equals 400 and (a) equals 250. The shelter capacity limits in Column B of Table 2 and the intensity levels in Column B of Table 3 measure the implications of these extreme choices. The remaining columns C-M in Table 2 present the shelter capacity reductions that occur when unpaved open space percentages increase in cells C4-M4.

The intensity levels in Columns C-M of Table 3 also decline with the increased unpaved open space percentages in Table 2. The tables clarify the choices available and implications involved. There are many more than presented. They change whenever one or more design specification values in the shaded cells of Table 1 change. The choices are in our hands. Measurement and evaluation of existing projects can help us understand the related consequences of design specifications, shelter capacity, and intensity decisions for all building design categories within a correlated mathematical spectrum of shelter capacity options. Evaluating these choices can help us acquire a better understanding of the places we create around the shelter we inhabit within the limited Built Domain we must define.

Walter M. Hosack: August, 2023



Photo by David Brooke Martin on Unsplash

 


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