July 2010


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Obtaining LEED Credits With Controls

What can we do to make our facility greener?

Steven R. Calabrese
Steven R. Calabrese
Control Engineering Corp.

Contributing Editor

Leadership in Energy and Environmental Design, more commonly known as LEED, is a big deal nowadays. For anyone maybe only vaguely familiar with the term and the concept, a little background:

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The LEED green building certification program was created by the U.S Green Building Council (USGBC), a nonprofit organization formed in 1993. The first version of LEED was launched in the year 1998, and has gone through several version revisions since that time. In general, LEED is a rating system designed to rate both new and existing buildings for “sustainability”. Now in its thirteenth year, the LEED program has matured into the accepted standard of evaluating how green a facility is or can be.

In 2009, the LEED for Existing Buildings program (LEED EB) underwent another revision, and is since termed LEED for Existing Buildings: Operations & Maintenance (LEED EB: O&M). This writing will discuss this program in particular, however noting that the LEED for New Construction (LEED NC) is a similar rating system in terms of categories and individual credits.

The LEED EB: O&M program currently has (7) categories, containing a total of (110) credits that can be attained toward LEED certification. The categories are as follows, with the number of credits for each category shown in parentheses. For the purpose of this column we’ll limit our conversation to the first five categories.

Sustainable Sites (26)
Water Efficiency (14)
Energy & Atmosphere (35)
Material & Resources (10)
Indoor Environmental Quality (15)
Innovation in Operations (6)
Regional Priority Credits (4)

A building attaining all (110) credits would be certified as Platinum, and would likely make it into the USGBC hall of fame, if there was such an entity!  Realistically, a building will fall into one of four certification levels:

Certified (40-49 credits)
Silver (50-59 credits)
Gold (60-79 credits)
Platinum (80-110 credits)

The title of this column suggests that there are things we can do with controls to attain LEED credits, and while it’s true that there are certain things that can de done with the Building Automation System (BAS) to achieve “green points”, understand that there is a lot more to the LEED program than just controls-related items. Nevertheless, in a building equipped with a BAS, these items that are controls-related become the “low-hanging fruit” on the LEED checklist, and should be pursued to the extent that the BAS can make provision for. The rest of this article will list out each of the five LEED categories to be discussed, and will address those credits in particular that can be influenced via the proper and innovative use of the BAS.

Sustainable Sites

8: Light Pollution Reduction

Perhaps the only credit under this category that can be impacted through the use of controls and the BAS is credit 8: Light Pollution Reduction. This credit refers to the “pollution” that (mainly exterior) lighting creates upon the environment. Sort of like when you’re in the city or suburbs at night and you look to the sky to view the stars, as compared to being out in the boonies and doing the same…a lot harder to see those constellations from the “city of lights”, right?

Using the BAS to keep exterior lighting turned off when not needed, or ensuring that interior lights are turned off when the building is not occupied, can feasibly help attain this credit.

Water Efficiency

1: Water Performance Measurement
3: Water Efficient Landscaping

A number of ideas here, the one that jumps out at me the most is with regard to credit 1: Water Performance Measurement. Metering has become a big thing these days in the building automation industry. The old axiom, “If you can’t measure it, you can’t control it” applies, and with the current metering technologies at our disposal, we can measure many things that once were, shall we say, immeasurable, at least with regard to the BAS. Of course we’ve been measuring and monitoring electrical power consumption for some time now, and other utilities have become easier to monitor as well, such as natural gas and “city water”. Traditionally monitored via site meters and read by the local utility providers (for billing purposes), now gas and water can be monitored electronically as well, the signals fed to the BAS. With that information now in our system, we can feasibly set up schemes that monitor the usage and implement a curtailment program if usage reaches or exceeds a certain threshold.

Credit 1 under this category deals with the ability to monitor and record water usage, from both a building-wide and a “sub-metering” standpoint. The key to this credit is being able to monitor water usage electronically, such that the information can be brought in to the BAS and logged. The city meter may or may not be able to give an electronic signal. If not, you would need to install an additional meter, specifically for this purpose. Of course any sub-metering would need to be done with additional meters as well.

Credit 3 is broken down into three parts, each dealing with the reduction of potable water usage, each in different, increasing percentages of reduction. The most obvious use of the BAS with respect to this credit would be to take “supervisory control” of the outdoor sprinkler system, and disable it when not needed. This can be done by setting up the BAS to utilize online weather forecasting, and prohibiting the operation of the sprinkler system if the forecast is calling for rain. Another method, albeit more costly to implement, would be to install soil moisture sensors and wire them into the BAS, in order to determine when irrigation is required.

Energy & Atmosphere

1: Optimize Energy Efficiency Performance
2: Existing Building Commissioning
3: Performance Measurement

[an error occurred while processing this directive] Credits 1 and 3 have everything to do with energy metering, in essence, electrical, gas, and BTU monitoring. I suppose we need to talk about credit 3 before we discuss credit 1, as it follows that you need to be able to “measure” before you can “optimize”. That said, the BAS will need to monitor electricity and gas usage, at a minimum, via meters installed at the service to the facility. In the case of electrical meters, this can come in the form of one main meter, or multiple “submeters” located throughout the building. For gas, it’s more typical to monitor at the main entering the building. BTU monitoring incorporates both flow and temperature monitoring (as with chilled water usage monitoring) into one metering scheme. Knowing the flow rate through the mains, as well as the temperatures of the water on both the supply and return sides, a calculation can be made, either via the BAS or via an application specific monitoring system, resulting in the energy usage of the equipment that is utilizing the chilled water.

Credit 2 is broken down into three individual credits: Investigation & Analysis, Implementation, and Ongoing Commissioning. The first part deals again with the monitoring aspects that need to be put in place in order to carry out the task and earn the credit. “Implementation” deals with what is to be done with the information gathered, insofar as to the general commissioning processes. And "Ongoing Commissioning” refers to the need for the building to be consistently maintained and continually evaluated and “tweaked” to sustain optimum performance. This is where the BAS earns its keep, as there are many features, both custom and built-in, that can be implemented to meet this credit. Trending and alarming, run-time logging, maintenance interval reporting, and corrective action flagging, are just a few of the features that can be set up via the BAS.

Materials & Resources

Quite honestly, I personally can’t come up with anything related to controls that can help attain a credit in this category. Take a look at the available credits, and if you can find something, please let me know!

Tip of the Month: There are many good resources on the web with regard to green buildings and the LEED certification program. For a checklist containing a list of all categories and all available credits, you can visit the USGBC website at www.usgbc.org . Just follow the links for the program you are interested in (LEED NC, LEED EB: O&M…), and click on the link that takes you to the checklist. It’s an Excel spreadsheet, available for free download, and contains the most up-to-date information on the credits. Go Green!

Indoor Environmental Quality

1.2: IAQ Best Management Practices – OA Delivery Monitoring
1.3: IAQ Best Management Practices – Increased Ventilation
2.2: Occupant Comfort – Occupant Controlled Lighting
2.3: Occupant Comfort – Thermal Comfort Monitoring

Credit 1 (parts 2 and 3) addresses the need for outdoor air monitoring and control. Through the use of outside airflow measuring stations and proportionally controllable outside air dampers, we can attain these credits. Monitoring and control can be done with individual I/O via the BAS. In addition, there are certain manufacturers that endeavor to facilitate the task by incorporating both monitoring and control into one device, basically an outdoor air damper that has flow measuring and control capabilities built into one package.

Credit 2.2 is a lighting credit, and requires that the BAS interface with the lighting systems in some manner. Not all that difficult these days considering that, even though typically the BAS and lighting control systems are separate from each other, they’re both microprocessor-based, and can communicate with each other via standard communication protocols. That being the case, the BAS can certainly have an influence on achieving this credit. An example would be if an occupant entered a VAV zone, hit the override button on the zone sensor to put the VAV system into an occupied mode, and at the same time the lights for that zone came on…maybe not the best example, but at least you can see where we can go with this concept.

Finally we come to the end, credit 2.3 addresses the need to monitor the occupant spaces and log what the credit refers to as “thermal comfort”. While that may be difficult to define, the BAS at least can measure temperatures within all controlled zones, and chart these temperatures over time in order to attain this credit. Of course one person’s definition of thermal comfort may be another person’s definition of “sweltering” or “freezing”, the objective element of the term can be monitored and logged via the BAS, thereby attaining the credit.


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