02/08/2009

Sustainability and Durability

Sustainable Building is not a product, or an agglomeration of products, it is a process.


TE = EE +OE


TE Total energy


The energy consumed during the life cycle of a building, it's carbon footprint, including construction.


EE Embodied energy


The energy consumed in the construction of a building, a one off investment, and the result of decisions taken at the concept stage of the design process.


OE Operational energy


The energy consumed during the operational life cycle of a building, excluding construction, and is the direct consequence of decisions taken at the concept stage of the design process.


Protect EE investment


OE is usually between 30 and 60% of the EE, depending on criteria. Inefficient buildings usually have a lower EE payload. Most of the EE in a building is invested in services (wiring, plumbing etc).


Protecting EE investment is more important for efficient buildings


The greater the energy invested in the construction phase of a building, the more crucial it becomes to protect that investment. Improved energy efficiency may have negative effects on durability: increased insulation and reduced ventilation may adversely affect building elements susceptible to moisture.


Durability is directly proportional to environmental impact


The environmental impact of a building that lasts 40 years is twice that of a building that lasts 80 years, regardless of what is built. Durability is defined as the ability of a building and it's components to perform the required functions over the specified Design Service Life without unforeseen costs for maintenance or repair.


Durability is the result of Brief, Design, Specification and Workmanship, and the therefore the joint responsibility of Clients, Designers and Constructors. Design criteria affect both durability and TE.


Conclusion


Buildings should be built to last. Sustainable buildings should be designed to last longer. Maintenance should be should be cheap, clean, easy and perfectly programmed. Clients, Lenders and Governments should get seriously interested in Durability. And if "Durability" is a difficult concept, use "Quality" instead. It's the same thing.


Credits: This post is my interpretation of an online presentation by Peter Yost/LLC

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