I read with great interest the Liability & Litigation column by Gina Vitiello, LEED AP, on the appeal of the LEED certification awarded to Northland Pines High School in Eagle River, Wis., in the August issue of HPAC Engineering (“Appeal Raises Questions About LEED Certification,” http://bit.ly/dytTU7). Unfortunately, these kinds of problems were inevitable from the get-go. I believe this column will be a wake-up call for architects and engineers.
I have been concerned about liabilities arising from green design guidelines for about a year now. In June, I gave a presentation at NeoCon in Chicago. One of the points I raised concerned legal liabilities and the U.S. Green Building Council's (USGBC's) refusal to accept any responsibility for the “advice” about guideline compliance it gives to architects during the design process.
This issue, as the column stated, will not go away; it will be amplifying in the future. Engineers and architects should be aware of the potential dangers they face by blindly following green design guidelines. Insurance agencies already are well aware of them.
Stephen J. Vamosi, PE
Intertech Design Services Inc.
The USGBC seems to prey on undereducated, underinformed owners and the public. Now LEED seems to have wormed its way into contract documents. Some now even require that a certain level of certification be achieved. This is very common with federal projects. Maybe LEED should include statements that the certification system shall not be used to contractually bind architects, engineers, and contractors to meet any level of certification. Liability and responsibility should be synonymous. If LEED has no legal liability, why should it be given any responsibility in making sure a contract is green?
excerpted from HPAC.com
I knew this was coming. I watch them put “frosting” on buildings to gain LEED points regardless of its actual value to the building. The worst part is that most of these are public buildings, and our tax dollars are going to waste. The principles of green construction are good; certification brings out all of the fancy language, worthless additions, etc.
LEED is a standard of relative greenness, not a contract document for overpaid lawyers and underemployed engineers to litigate. Before LEED, there was little awareness of green design principles, much less an understanding of related issues.
While I have my own gripes with the LEED scoring and certification system, the LEED process has been a powerful force in bringing green design mainstream. Just the fact designs can be 40 to 60 percent more efficient with little or no increase in first cost is testament to the opportunity for the United States to become more competitive and less dependent on fossil fuels.
Supersymmetry USA Inc.
There long has been plenty of awareness of energy-efficient, sustainable design, and it was implemented to the extent clients were willing to invest in the future value of their projects. What we lacked was a bureaucratic entity to take credit for it. Now that we have one, it should be consistent and objective, or it will not be sustainable itself.
Thank you for printing the column on the appeal of the LEED certification awarded to Northland Pines High School. It reinforces my concerns about LEED.
In Cincinnati, The Herald Building received LEED certification despite the removal of a dozen houses and associated mature trees. I am not saying this was a bad redevelopment project. I just do not understand how removing trees and using new materials to construct an office building in a city with a surplus of office space meets the USGBC's implied intent to preserve the environment.
Jim Drye, PE
I found the article “Fan Selection and Energy Savings” (August 2010, http://bit.ly/aID9c9) very useful.
I come from an industrial environment. We have many HVAC units on the roof. The fan blows into a discharge plenum. From the plenum, three or four ducts go in many different directions. According to the article, the plenum should be two-and-a-half times the diameter of the duct from the discharge of the fan. I have seen different sizes of plenums, but haven't seen any article or best practices concerning plenum design and how to tie discharge ductwork from a fan into a plenum for the best efficiency. Can the author help?
Milford Center, Ohio
The article gives a recommendation for the length of straight duct required at the discharge of a fan to achieve a uniform velocity profile of fluid before any free discharge or elbow. This will eliminate system effect at such a transition.
I understand space often is a luxury not present in HVAC designs. For such instances, AMCA Publication 201-02, Fans and Systems, provides excellent guidelines. Page 26 of the publication gives a graph used to calculate a system-effect factor to account for various installations. This factor can be added to static pressure during design of a system.
Later sections of the publication give charts for various installations that need to be used in conjunction with the graph on Page 26. Pages 30 and 31 give charts for finding the correct system-effect curve, depending on the amount of ductwork between a fan and a free discharge or, in your application, plenum.
AMCA Publication 201-02 gives a recommendation for straight ductwork. A built-in transition will alleviate some of the system effect associated with the rapid expansion of air at a free discharge.
Greenheck Fan Corp.
While I enjoyed the column “Opportunities Abound for Water Technologies” (Engineering Green Buildings, July 2010, http://bit.ly/axCltb) and agree that the architecture, engineering, and construction community has a role in saving water, I think the author is missing the big picture in conservation efforts.
The largest user of fresh water (48 percent) in the United States, according to the U.S. Geological Survey (USGS), is thermoelectric power. States such as Arizona, Nevada, and New Mexico, where water is scarce, use a closed-loop cooling system, unlike most states, such as Illinois, which use a once-through cooling system. To show how much can be saved, Arizona uses 100 million gal. of water a day for thermoelectric power, while Illinois uses more than 11 billion gal. — 110 times more than Arizona. If all of the thermoelectric power plants in the United States used a closed-loop system, according to the USGS, more than 111 billion gal. of water could be saved per day. That is more than 25,000 times the 3.59 million gal. used for domestic purposes.
The second-largest user of fresh water (35 percent) is irrigation. Drip irrigation not only saves water over impact sprinklers, recent tests show it saves up to 95 percent of chemical fertilizers.
During a recent LEED conference, I heard a discussion about greywater usage, with one consultant saying that, with the current rate structure, payback is 100 years.
Why are we proposing to spend billions of dollars to save less than 1 percent of the water? Isn't a better solution to get the big users of water either to implement water-conservations measures, such as closed-loop cooling, or pay their fair share of the water being used?
Mechanical Concepts LLC
Less than 5 percent of water in most thermal power plants is lost to evaporation; most of the rest just has its temperature raised, so it's misleading to look at pass-through water use as actual consumption. The same analysis holds true for most cooling towers in buildings: a lot of water flow, little actual loss.
As for irrigation, it is a major water consumer and incredibly sensitive to pricing, which is why it's almost untouchable politically in most areas. There are a lot of good technologies for monitoring irrigation-sprinkler water use that are reducing overall consumption.
As for greywater use, it's impossible to say anything about payback without knowing the systems analyzed and the local rate structures. Greywater reuse is an option that should be considered for outdoor irrigation and cooling-tower-water makeup for most new buildings.
Urban water use is about 11 percent of total U.S. consumption, but it's the costliest in terms of energy use and treatment requirements. Making water conservation a priority in new-building design and major renovations makes all of the sense in the world; cost-effectiveness is there in most cases, if one analyzes the full avoided costs of water savings, as well as the direct costs and benefits. In addition to doing the right thing, mechanical design firms specializing in water conservation are going to find a lot of new business opportunities over the next five to 10 years.
Jerry Yudelson, PE, MBA, LEED AP
Regarding the article “Pressurization Control in Large Commercial Buildings” (February 2010, http://bit.ly/cu6NYo), has there been any research into, or is there a method of quantifying, potential savings from building-pressure control? A lot of retrocommissioning projects have issues with pressure, but because of a lack of savings/payback calculations, they get glossed over in favor of high-savings energy-conservation measures.
Nick Tisdell, CEM
Uhl Company Inc.
Maple Grove, Minn.
We've done custom spreadsheet calculations for estimating energy savings. I'm not aware of any research or calculation templates that have been developed in detail.
Most of the time, the energy savings related to optimizing building-pressurization control come from reduced fan speeds or reduced infiltration (reduced heating/cooling loads). It's a tough one to calculate the savings for, though. Oftentimes, it's a measure with a low implementation cost, so owners may be OK with estimating the savings up front, based on a rough calculation, then truing up the savings estimate post-implementation based on measured data.
There are papers such as “Commissioning and Envelope Leakage: Using HVAC Operating Strategies to Meet Design and Construction Challenges” (http://bit.ly/ddEZK4), as well as spreadsheet-based energy-savings calculation tools for other retrocommissioning measures from the likes of the California Commissioning Collaborative (www.cacx.org), but I haven't found anything specifically addressing the quantification of savings related to building-pressurization optimization.
Dave Moser, PE
Portland Energy Conservation Inc.
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