Welcome to our 5 part series on the Smart Enclosure System. This is part 2: The Smart Enclosure System Principles and Calls to Action Overview.
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In starting with basic building science and our ecological predicament, we distilled seven basic principles to guide us. Importantly each principle represents a specific call to action, as well. After all, this is about taking climate action.
Let’s list and discuss each, briefly:
First is the principle of lower embodied carbon: and the call to action is to Use fewer construction materials and ensure that the materials used have low embodied energy to significantly reduce short-term carbon emissions.
The harvesting and manufacturing of building materials, and renovation and demolition of buildings is responsible for approximately 10-20% of all human-made greenhouse gas emissions.
To make a difference today it’s not enough to achieve Passive House levels of efficiency. Even 30 years out, about 80% of the carbon, the building emits, will not be from its operations but from its making. And if you’ve build a net zero building, then 100% of emissions are embodied emissions.
The structure of the building can account for as much as half of the building's total carbon emissions, so reusing old buildings and renovating existing structures is by far the best thing we can do.
We should also minimize waste, and use less new materials. The new materials should be produced with less energy intensive processes and have higher recycled content. And we should use plant-based materials that have a negative embodied carbon value. We should limit the use of foam and mineral wool insulations, as well as metal and concrete, that have relatively high embodied carbon, and utilize instead materials with a negative carbon value like wood structures and natural fiber insulations.
Next, closely related to embodied carbon, is:
The second principle is carbon sequestration: with the call to action to Lock as much carbon storage into the structure as possible and provide long-term emissions security for generations to come.
We can simply bury atmospheric carbon in our buildings - working with nature, instead of fighting nature. Through photosynthesis, trees and plants are removing carbon from the atmosphere and capturing it. If we then put the wood and plant materials into our building structures our buildings can lock up the carbon through 2100 and beyond, breaking the carbon cycle.
To be a sustainable solution, good forestry practices that support greater biodiversity and ecosystem health are required. And by using our forests as a building material resource, we can actually increase the rate of forest CO2 absorption in a regenerative process, and create a virtuous cycle of negative carbon emissions.
Again, plastic and mineral wool insulations, steel and most concrete have no carbon sequestration capabilities. Minimize their use.
Today, we see massive wood buildings going up 10, 20, 30 stories and bigger, so really anything is possible. Our cities can become and must become, giant carbon banks.
The third principle is lower toxicity: and the call to action is to Protect workers, occupants and the biosphere by choosing products that have lower toxicity in manufacturing, construction, and disposal. Use fewer plastics and less plastic foam.
Human-made, bioaccumulative, and persistent toxic chemicals are now found the world over. After the packaging sector, the building sector is the biggest user of plastics. Ensure lower risk of toxins by using the Precautionary Principle, which exhorts us to resist products for which its ultimate effects are disputed, when selecting materials.
So we want to lower the toxicity of what we’re designing and building with. From the Greenpeace Plastics pyramid to the Living Building Red List and Declare Labels, the Precautionary List, the Healthy Building Network Pharos Project and more we have the tools to make better choices.
After all, you don’t have a cigarette habit, do you? Kick the toxic materials habit too. Make less toxic choices for your building assembly materials. The excuses are getting thin.
Four is more natural materials: Use natural materials that require minimal processing, while providing substantial health and carbon benefits.
Natural materials typically require minimal processing and therefore have significantly lower embodied carbon. They are a healthier choice for indoor air quality, as they often help buffer humidity levels and, when properly selected, have no VOCs. Our building enclosures should not just not make us sick. They should help make us healthier.
Source more natural materials such as wood fiber, wool and cellulose insulations, timber structures and lime plaster finishes.
The fifth principle is Smart vapor, air, and thermal control: The air, vapor and thermal control layers should provide Passive House levels of energy efficiency, comfort and durability.
Today, we have access to materials that provide a robustness previously unavailable to the industry.
Airtightness maximizes the effectiveness of the insulation and optimizes occupant comfort while reducing the risks of assembly moisture damages. The insulation should be surrounded by airtight layers with a continuous inboard and outboard air barrier. The inboard air barrier should be a smart vapor retarder. In heating dominated climates, the outboard air barrier should be vapor-open.
Smart vapor control ensures that highly insulated assemblies, which tend to stay wetter longer, have maximum drying potential over the course of the seasons. Consequently, the insulation is drier, and drier insulation is better at insulating. Wood, wool, and cellulose insulations help buffer moisture levels.
Thermal control is fundamental to comfort and energy efficiency. It must be continuous. Where the insulation is discontinuous, thermal bridges result, causing discomfort, inefficiency, condensation, and ultimately, moisture damage. Insulations like densepack wood fiber and wood fiberboard can provide additional benefit with enhanced thermal buffering.
It's all basic building science, basic Passive House stuff. Be sure you understand it.
Sixth is 100-yard durability: Maximize the building’s climate mitigation effectiveness by making it functional for generations.
Having to replace or rebuild portions of the enclosure adds significant embodied emissions over the building’s lifetime. To ensure durability, we need to use reliable materials that are put together correctly, are repairable, and are protected from damage for the life of the building.
This can be accomplished by using materials that are tested for 100+ year durability.
Materials like spray foam that will degrade do not belong in a high-performance enclosure.
Protect the air, vapor and thermal control layers with a service cavity inboard, and a back-vented rainscreen outboard to prevent damage in the course of regular use and during future renovations.
Stop compromising, and optimize durability. Build your buildings to last.
Finally number seven: Fully integrated performance: Integrate the performance of the enclosure into the design of the whole building to provide beauty, delight and utility, Passive House energy efficiency, healthy and happy occupants, and a positive energy and carbon emissions balance.
Siloing systems will result in an inefficient building, with each individual system only accomplishing one goal and producing a building that is less than the sum of its parts. The goals should be ambitious, supporting operations that have Passive House levels of efficiency, zero energy, and carbon negative outcomes. The buildings should be objects of Desire, they should be loved.
The Smart Enclosure System is a framework to make all these principles, these calls to action, possible. The more we realize these principles, the smarter the enclosure becomes. The enclosure is a complete system, a system whose intelligence is built into the structural fabric.
See you in part three, The Three Tiers.