Engineering a Sustainable World

Building design focuses so much on architecture that many people forget that it's the engineers who make all the building systems work, from structural systems to heating, ventilating and air conditioning (HVAC) to plumbing, lighting, electricity, technology systems, external water supply and waste disposal, fire protection and life-safety systems. About 15% to 20% of the construction cost of a typical commercial building is taken up by engineered systems, not by the building structure or furnishings, while an additional 15% to 20% comes from the civil construction outside the building.49 It's easy to see that the engineer's role is critical to achieving high-performance building design with economy.

Engineering is all about economy of resources. Someone once told me that a good engineer is someone who can do for $1 what a mediocre engineer can do for $2. What would a more substantial green building design role for the engineers look like, and how would that lead to economy of means to achieve high-performance results? We discuss this in several sections, including Rightsizing, Integrated Design and Energy Conservation,

Sustainable engineering vs."post-modern"engineering

Category

"Post-modern"/ Conventional Engineering

Sustainable/High-performance Engineering

Buildings

Suburban greenfields; New buildings preferred

Urban infill; Adaptive reuse of building stock

Energy Use

Meet energy code; Reduce energy use vs. code; Make incremental improvements; Buy power from local utility

Exceed code by 50%; Reduce absolute energy use; Develop new systems and methods; Use on site power such as co-generation

Economics

First cost is major driver; Look only at project economics

Life-cycle cost analysis;Triple-bottom-line thinking

Ventilation

Forced ventilation; Sealed windows; High-pressure central systems

Natural ventilation; Operable windows; Low-pressure distributed ventilation

Climate control

Design with components; Narrow temperature band; Consider only HVAC system economics

Design whole systems; Expanded temperature band; Look at health and productivity of the workforce

Water use

Specify efficient fixtures

Reclaim and reuse rainwater/ graywater

Stormwater

Convey off site to rivers and ocean

Detain, retain, recharge, re-use on site

Wastewater

Convey off site to treatment plant

Treat and reclaim for on site use

Materials selection

Environmental effects not considered

Life-cycle assessment of materials; Use recycled materials such as fly ash for concrete

but consider the above table that illustrates how engineering needs to change to promote sustainable design. I contrast sustainable or high performance engineering against the conventional state of engineering design for "post-modern" architecture.

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