Abstract
It is only in the case of fire that materials are considered by the American International Building Codes across an aggregation of scales (i.e., a building, a block, a district) leaving many other essential factors of material performance neglected. Mostly ignored are environmental and social parameters that also present forms of risk. This chapter uses the cities of New York and Chicago and three performance characteristics as case studies to examine additional material impacts at the city-scale. Case studies analyze material maintenance requirements against urban disinvestment, moisture absorption capacity against mold rates within flood-prone communities, and embodied carbon against material lifespan averages across cities. Findings reveal connections between material performance and economic, health, and energy implications across the city, suggesting the need for more broadly defined urban material performance standards.
TopIntroduction
Early American city builders developed material regulations that define where and when specific building materials can be used based on a singular urban risk, conflagration. Over the next century, building codes translated fire protection goals into rules addressing vulnerabilities at the building scale—including occupancy, building height, and property line proximity—to define the range of allowable building materials in specific locations. The results are twofold. First, the codes produced a product-scale material performance mentality in the construction industry with a myopic set of criteria. Second, the system gave rise to urban neighborhoods defined by a dominant building material with correlating delineations of socioeconomic vulnerability.
The current model of material-defining building codes succeeded in bolstering fire protection in American cities but also established a restricted system that overlooks less obvious performance outcomes. For example, the current regulations assume a static environment, do not account for intersectional urban risks, consider hours-long timeframes only, and ignore the impact of cumulative performance across neighborhoods. The term “intersectional” is used here as defined by legal scholar Kimberle Crenshaw to refer to the compounded impact of disadvantage from multiple sources (Crenshaw, 1989). By limiting the complexity of building codes, we also limit their capacity to adapt to unforeseen social or environmental impacts.
This chapter uses the cities of New York and Chicago, and three performance characteristics as case studies to examine material impacts beyond combustibility at the city-scale. The first case study investigates material maintenance requirements and urban disinvestment. Findings include a correlation between high-maintenance material concentrations and urban disinvestment indicators, particularly within economically vulnerable communities. Secondly, the chapter analyzes the evolution of moisture absorption capacity within combustible construction over the twentieth century and studies mold rates within wood-frame neighborhoods. Results suggest a link between highly absorptive material areas, flood-prone communities, and health risks. Finally, the chapter considers each construction type according to embodied energy and material lifespan averages across cities. This final case study also raises the issue of local resource availability and variations in embodied energy according to regional geology and fire-code requirements.
Overall results suggest the need for further analysis across intersectional material and urban risks and increased attention to material performance at the city scale. The structure of building codes and the visibility of their potential impacts must become more legible to foster experimentation, public conversation, and to improve the adaptive capacity of urban material stock.
Key Terms in this Chapter
Life-Cycle Analysis: Measurement of total energy or total carbon used (and sequestered) in production, construction, and disposal of a material.
Building Abandonment: The evacuation, relinquishment, and often neglect of a property by its owner.
Building Codes: Municipal regulation defining construction and design guidelines. The International Code Council describes its mission as the creation of model codes to protect building occupant health, safety, and welfare.
Intersectionality: The compounded impact of disadvantage from multiple sources.
Flashing: Part of a drainage system, typically protecting a joint between materials.
Building Stock: The collection of buildings in a city or region.
Construction Types: Material assemblies defined by building codes according to their fire-resistance rating.
Underlayment: Similar to sheathing, but operating between floor structure and floor covering.
Sheathing: Protective covering, typically between primary wall structure and exterior cladding.
Service Life: Measurement of material durability; the period during which a material component of a building is functioning correctly, withstanding wear and decay.
Performance Codes: Giving directions that the building as a whole perform to a certain standard.
Prescriptive Codes: Giving directions that each component is built to a certain standard.
Urban Disinvestment: The economic decline of a neighborhood.
Building Lifespan: A building’s expected useful service life. This is often up to double the average building age.