|June 22, 2011||The Sustainable Building Advisor||no comments|
|June 22, 2011||The Sustainable Building Advisor - Integrated Building Design||no comments|
|June 22, 2011||The Sustainable Building Advisor - Insulation and Conductive Heat Loss||no comments|
|June 22, 2011||The Sustainable Building Advisor - Cost of Sustainable Building||no comments|
|June 22, 2011||The Sustainable Building Advisor - New Building Codes and Energy Performance Benchmarking||no comments|
I’d like to invite building practitioners to share thoughts on current building practice and sustainable building practice on this blog.
I would like to begin this blog by making the argument that sustainable building practice requires its practitioners to adopt a collaborative business model and that collaboration is a core tenant of sustainable building practice.
Contrary to some practitioners’ claims, my experience consulting and teaching sustainable building practice is that few if any of us are real masters of this rapidly moving science and craft. Technologies and accepted practice are changing rapidly and require a wide array of knowledge including site stewardship, building systems for energy efficiency, systems, controls and equipment for building comfort and occupant well-being, and meeting new and changing performance code requirements, among others. Collaboration is an open approach to working with our colleagues in this industry to share knowledge on means and methods for sustainable best practice. The free sharing of knowledge among practitioners provides the stable of information resources necessary to operate our businesses successfully in a rapidly moving new sustainability-driven economy. Our New York Upstate Chapter of the US Green Building Council holds monthly meetings at various locations in New York and provides a venue for practitioners, developers, code officials, and anyone interested in sustainability and sustainable building practice to meet and make contacts to help develop your collaborative practice. Anyone can sign up for notices of monthly Chapter meetings at the following web address: http://visitor.constantcontact.com/manage/optin/ea?v=00147Jgk4c64VNNviOLYdDWTQ==
Sustainable building is action and it is process. It is a change from the traditional practice of design and construction of buildings. IBD begins with the understanding by the project owner, designer and contractors that more time, expertise, and assessment is placed in pre-design, that design will have more detail than traditional practice, and that design and construction team dynamics will be important and must be structured.
The collaborative IBD structure has been described in detail by ASHRAE and AIA in their respective integrated building design and integrated project delivery recommended practice documents, and is required practice on LEED projects.
AIA describes the approach as one that “integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to optimize project results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction.” Implicit in this approach are the three most important verbs of sustainable practice - plan, collaborate, document.
Interest in IBD stems from the recognition that placing more effort into a building project early in the process (front-loading) can save money and improve outcomes. Patrick MacLeamy, CEO, HOK developed the “Macleamy Curve” in order to graphically show the advantage of integrated building design process. This widely reproduced curve plots the relationships of four factors - ability to impact cost, cost of design changes, historical workflow, and integrated project delivery workflow – against the timeline of a project, from pre-design to operation. The graphs show that the cost of any change to the design rises with each subsequent project phase, while the ability to affect costs and functional capabilities declines steadily from its peak in pre-design.
The curve demonstrates the value of front-loading the process in order to provide the greatest amount of information early in the process there the information can have the greatest benefit to project outcomes.
The use of IBD process will reduce project cost, lessen uncertainty in cost and schedule, and improve construction quality. And where the program objective includes qualifying the project under LEED, this is a required process.
The amount of energy conducted through a building envelope is measured by insulation R-value . We know insulation is important in the building envelope, but the question is, how much insulation should we be putting in walls, floor, and ceiling? It should be based on costs versus payback. The cost of adding additional insulation is fairly linear; that is, twice the insulation is twice the cost. The same isn't true for what the insulation does, however. Doubling the insulation does not halve the conductive heat loss.
Table 1 shows results of increasing insulation on heat flow. As shown on the graph, R-4 effective insulation reduces heat flow by 82% and R-20 by 96%. However, going from R-20 to R-40 results in only a 2% reduction in heat transfer.
This data can be compared to insulation thickness based on its R-value. Table 2 shows insulation effectiveness per inch of thickness for insulation having an R-value of 3.8 per inch (delta T 40oF).
As shown, going from 1” of insulation to 3” reduces energy loss by 11%, while going from 3” to 5” reduces loss by less than an additional 3%.
This demonstration, based on data which is generally available from the insulation manufacturer, shows the diminishing returns in terms of building performance as more insulation is added to the building envelope and therefore can be useful incomparing insulation cost and effectiveness and in deciding the best use of construction or remodel dollars.
When we attempt to calculate how much it will cost to “build sustainably” the answer always depends on where we are starting from. Today every design and build program should begin with a set of clear performance objectives as part of the owners project requirements and include someone on the project team designated to document that these owner requirements and the requirements of building codes and relevant incentive programs are met both in the design and in the construction of the building. If this is the case then it should add little to the project cost or schedule to meet LEED certification criteria. However, U.S. Department of Energy (DOE) research places effective codes enforcement at less than 40% nationwide, and this suggests that significant improvement in current building practice is needed simply to meet building code requirements. It is a great leap to achieve sustainable building practice for those practitioners whose current building practice is to meet only those code requirements that they can expect will be checked by local code officers. Greater enforcement of building codes as well as new inspection and testing are at hand. States like New York who receive state energy program funding under the American Recovery and Reinvestment Act (Recovery Act), have committed to achieve 90 percent compliance with building energy codes by 2017. It is expected that this will be achieved by a combination of additional training, greater emphasis on enforcement and State tracking of local codes enforcement. The new codes which are requiring demonstration by the owner and builder of meeting higher levels of building performance together with more robust enforcement of these codes are narrowing the distance between a code compliant project and one which can readily achieve sustainable building certification.
Building codes for years have provided prescriptive standards for construction of buildings. New building codes, such as IECC 2009 recently adopted in New York as NYSECCC mandate new design and construction requirements for greater energy efficiency in buildings. These include new requirements for addressing building operations as a whole, rather than as a series of parts, to be demonstrated by computer modeling in the design (including requirements for predicting energy loads based on building orientation, solar heat loads and daylighting), and actual performance testing following construction. Best practice voluntary programs like LEED go further to address a wide range of building design and construction activities that can have impacts on energy and water use, durability, occupant safety and health, and the environment.
The U.S. is moving toward building benchmarking and rating systems similar to those currently in place in Europe, Japan and Australia where building performance is accurately measured and the actual building energy use is published and displayed on a building by building basis. ASHRAE has developed a two-part building energy labeling program, the ASHRAE Building Energy Quotient (bEQ), which will be used to both identify the building predicted energy performance at the design stage and the actual building energy use in full operation. The ASHRAE scale ranges from A , which demonstrates net zero energy performance, down to F, which would indicate unsatisfactory performance.
As more of our buildings are built and renovated to stricter standards, buildings will be valued by how much better (or worse) the building performs compared to building code requirements, and more importantly, how the building compares with other buildings. Benchmarking is becoming the norm and we will increasingly see buildings valued on how well they perform.