LEED BD+C: New Construction v2 - LEED 2.2
LEED Platinum 2009
* This profile has been peer-reviewed by a USGBC-selected team of technical experts.
The below stakeholder perspectives address the following LEED credits:
SSc2, SSc5.1 EAp1, EAc3, EAc5, WEc1.1, WEc1.2, EQc6.1, EQc8.1, EQc8.2
Goals and motivations
What were the top overarching goals and objectives?
With this project, we wanted to create a balance between architecture and engineering, and build a space that everybody would be excited about when it was done. Knowing that we would have the first Platinum-certified building in Nebraska, we also wanted to demonstrate leadership in the industry and our community by creating a building that performs at the highest level possible and sets new standards for resource use.
Another goal was to collect data on the building that allows us to provide better consultation to our clients relative to LEED features. We do extensive analysis on the performance of our building and use this data to help our clients understand what they might expect for their own projects, knowing what we are achieving.
What were the motivations to pursue LEED certification and how did they influence the project?
- Cost/Utility Savings
- Design Innovation
- Market Competitiveness
- Organizational Priority
We believe that design features should be incorporated into the day-to-day operations of a building and that LEED certification has motivated us to continue working to improve the energy profile of our building. LEED certification has also engaged us more in the community, providing the opportunity to spread the word about our building's features, energy use, and the LEED process.
People have asked for payback examples on a LEED point-by-point basis. Our opinion is that in a synergistic LEED project like this one, credits and their associated savings are interrelated. The buildings that we are building today will be impacted by future legislative and utility rate changes that we can't foresee in detail now, so we feel that the value of buildings will become more about building and systems performance (both in regard to energy and indoor environment) rather than the current gross square footage scenario of the real estate market cost/value model. As an owner, we viewed this building as an investment and want it to maintain its value both in current and future market terms.
The cafe/break room is pictured on the right side with open office cubicles on the left.
Testing new technology (lighting control, for example) that might be different or cutting-edge in our own building was something we were willing to try. This is something many clients aren't willing to be the first to test, and we took advantage of this LEED project to experiment.
What were the most notable strategies used to earn LEED credits?
The building is really an energy success story, earning all 10 possible EA Credit 1 (Optimize Energy Performance) points. As mechanical and electrical engineers, our nature is to focus on energy, but we were also able to earn all IEQ credits on this project - even some we didn't initially think we would be able to pursue, like IEQ Credit 2 (Increased Ventilation). A lot of the strategies that allowed us to achieve these credits have to do with our typical design processes and the way we think about projects. We are always trying to strike that balance between energy efficiency and the indoor environment.
The site of the building is part of a mixed-use development and is still under construction with a future total of 21 lots. So while our office is not located in a dense urban environment, the mixed-use development has provided many benefits that helped us earn LEED certification and promises to provide opportunities for our future-planned LEED for Existing Buildings: Operations & Maintenance certification, as well. It is one of the first developments that was designed to include "Omaha by Design" guidelines, which take an enhanced look at constructability, walkability, and other aspects of sustainable neighborhood development and planning.
The strategies for meeting the daylighting and views credits were more architectural then electrical. Some daylighting strategies, such as reducing glare and ensuring uniform lighting, were really tricky and benefitted from the team approach.
All MEI employees are located in open cubicles, allowing collaboration and communication, and contributing to even daylighting distribution and views. Light fixtures are oriented above each row of desks. Ductwork from heat pumps on the mezzanine routes through the space with low returns to ensure good air distribution.
To enhance natural daylight penetration, we positioned skylights on the opposite ends of the building from where the vertical glazing was. We used small, high windows at the top of the building to allow light deeper into the space. We also implemented a digital lighting system that allows us to dim the lights at a fixture-level basis based on available daylighting.
The site we selected contributed to LEED WE Credits 1.1 and 1.2 for landscaping water usage. When we located here, there was already a man-made pond on the site, and we use it for rainwater catchment and irrigation of turf grass. There is also a recreational aspect to the pond, as our neighbors use it for fishing.
Eight-foot windows at floor level extend throughout this side of the building, and metal panels with daylighting glass above can be seen to the left. On the left side of the roof, the vertical-axis wind turbine is an emerging technology experimented with on this project. The business park pond is used for rainwater catchment and irrigation of turf grass.
What cutting-edge strategies or processes were implemented?
The most innovative aspect of this project, I believe, is the fact that we're able to track our systems so precisely - a rarity for such a relatively small building. Individual sub-meters for lighting, plug load, heat pumps, electric heat, and on-site renewable energy and the tenant space allows for the kind of precise energy accounting that I wish we had for all projects. The current sub-metering layout is also expandable to add more metering in the future.
Our interest in data tracking originally rose out of LEED's EA Credit 5 (Measurement & Verification), since not many projects seem to pursue it. Having sub-metering data available as a showpiece helps us identify the benefits of enhanced data analysis for owners who may not even track monthly data beyond paying utility bills.
View of the building exterior and parking lot from the southeast side.
Morrissey Engineering's use of an infrared camera to perform envelope commissioning on this project helped identify several issues that will help us work with our architectural clients to build better buildings. Specific examples included identifying wall cavities with missing or wet insulation; wall areas where drainage from decorative metal panels needed improvement; and significant thermal bridging from the exterior structural steel to the interior (unconditioned) stairwells. Providing this feedback loop to contractors and architects will help save time and money on future projects and close the loop for construction details.
Various community organizations and groups (including the local USGBC chapter, colleges, and other nonprofits), architects, manufacturing representatives, contractors, building owners, and other visitors have toured our building since substantial completion. As such, the 4940 Building serves as a teaching tool for the community, an example for future projects, and a focus for employee retention and client development. As our company and the energy economy continue to grow and develop, we plan to adapt to showcase new technology and operating schemes in the building.
How was the integrative process applied and what was the greatest benefit gained?
We were in a unique position on this project. Acting as both the MEP engineer and the owner allowed us to perform EA Credit 3 (Enhanced Commissioning) using in-house commissioning staff - independent of the design team, of course. Enhanced commissioning allowed for additional consideration of system operation and performance during the design and construction administration processes.
MEI’s office interior features eight-foot windows for daylight and views along the west perimeter, and continuous glazing on the north perimeter.
Use of commissioning and feedback from employee thermal comfort surveys have allowed us to strike a good balance of energy efficiency and occupant comfort during occupied periods. For example, during unoccupied periods, we have been able to lower the perimeter electric heat to adjust the temperature (controlled based on outside air) from the initial design set point of 30° F to 10° F during normal operating hours, and to disable this perimeter heat overnight and on weekends. This is acceptable since building heat pumps are adequately sized to heat the building, and perimeter heat was intended to only address comfort issues resulting from radiative cooling effects of glass in winter.
It was a huge advantage for staff to take on engineering and commissioning roles as the occupant comfort and operation satisfaction they were ultimately addressing were their own. Being a small company of 30 allowed for staff to take a large ownership role in their work, as well as pride in the team's success. Independence of the engineering design team was assured on this project, especially as the individuals acting as commissioning authorities were even not employees of MEI during the design process. Since we don't hire new commissioning agents for each of our projects, our typical protocol - including for non-LEED projects - allows for enhanced commissioning during design through a constant feedback loop and peer reviews by the commissioning agent, outside of the design team.
Another major team synergy occurred through a relationship with the University of Nebraska at Omaha. We have a great Architectural Engineering Masters program in town and have been able to hire at least one to three interns every year. Two of the students have done their senior thesis on this building. The first weighed each LEED credit in terms of applicability when we were looking to pursue certification; the second measured post-occupancy energy use in the building and compared it to the original LEED energy model. We found that actual consumption was around 10% higher than the original model showed. We wanted to not only understand why that was and what we could do about it, but also to see if we could revise the model to be more accurate. The biggest discrepancy in input was discovered to be the schedule of occupancy; with a staff of 30, we're somewhat flexible with our hours, so our occupancy duration was more like 6 a.m. to 9:30 p.m. (originally modeled at 8 a.m. to 5 p.m.), with some weeks varying from that by a significant margin. During commissioning, we adjusted results to be within 1% of our actual consumption by revising the model to account for that one input and the identified control issues. This process demonstrated the importance of accurate modeling inputs and building operation.
Aside from LEED certification, what do you consider key project successes?
Being the owner, tenant, and designer has enhanced our market competitiveness and helped identify the true value of points for other LEED projects designed by our company.
IWe have not created any recycling policies or sustainability goals since moving into the building because occupying a LEED-certified building has gotten our staff on board without having to dictate and police. I believe staff are proud of our contribution to the community through LEED certification. Our building has enabled participation in dozens of panels and presentations to organizations like AIA, as well as an ongoing local collaborative presentation effort titled, "What Comes After LEED."
Since moving into the building, which features preferred parking for fuel-efficient vehicles, 20% of employees have purchased new cars, and parking spots that were previously under-used are now sought-after commodities that fill on a daily basis. As a result, we plan to add more fuel-efficient parking in the future.
Our LEED certification really ties into how employees have bought into this project and now do things differently. Being in a mixed-use development, we have a walking trail that's around our pond. The other currently-constructed building in the development is a retail center that includes a restaurant, so employees can walk to lunch when they might otherwise have driven. There is also a fitness center across the pond that several employees have joined and there seems to have been an overall increase in healthy living interests among our staff. These types of things are an indirect result of the style of building we're in, and can improve overall productivity and quality of life for employees.
What were the most important long- and short-term value-add strategies and what returns on investment (ROI) have been experienced or anticipated?
Measurement and verification has proven to be an invaluable tool for daily operation because it ties all of the building systems together. While it's difficult to isolate paybacks for individual items, use of an integrated architectural and engineering design allowed for the building envelope, lighting, plug load, and mechanical systems to each contribute toward earning all of the available EA Credit 1 (Optimize Energy Performance) points. Lessons learned from this project experience have helped us improve energy modeling accuracy on future projects.
The pursuit of IEQ credits was important for us. As design engineers, we wanted to show that a high-performance, energy-efficient space can also be a comfortable and enjoyable place in which to work and spend time. So while ROI for things like a quality work environment with daylighting and exceptional indoor air quality are traditionally hard to quantify, they were made priorities - and our occupant surveys have typically produced very positive results.
What project challenges became important lessons learned?
One of the most important lessons was learning to make decisions regarding innovative and unproven technologies. When we designed the building, we designed it with a small vertical-axis wind turbine, an emerging technology in which we thought people in this region would be interested. We found that there is great difficulty in using wind maps to calculate expected output in city settings with surrounding landscaping and buildings. Through measurement and verification, we have tracked the actual output of several different vertical-axis wind turbines and compared it to expected power production, and have often found these values to be quite different. In addition, the technology of the wind turbines themselves has proven inconsistent. The original turbine had to be replaced due to ongoing bearing issues with a new manufacturer and model that eventually failed under extreme wind conditions. As a result of our experiences, we have given this feedback to clients as we continue to track emerging technologies.
A second lesson learned concerned our lighting control system. We have an open protocol digital lighting control system, called DALI, which enables us to set up control strategies for each individual ballast. This system allows us to extract maximum energy savings from our lighting system by enabling the maximum amount of energy control. In a 30-foot-long row of lights, we're able to have four different light levels based on available daylight. This means different fixtures going up and down at different rates and different maximum and minimum percentages, which avoids us being stuck in the worst-case scenario in which the desk getting the lowest daylight is controlling the rest of the office area. With this benefit, however, come controls, equipment, and programming that require maintenance. Through this process, we learned how to better match energy savings with a client's ability to maintain complicated systems (such as lighting and HVAC) because without proper maintenance, performance suffers.
Last, we've learned things about renewable energy that may impact our decisions on future projects. Since the building opened, we've installed a sizable solar array. We've had predictable output and it works everyday with no weather issues. Looking at calculated payback for solar PV, it may not be as good as wind. But given our geographic location, system reliability made this a better option than wind.
Dual-layer solar panels provide electrical output that exceeds their rated value, due to the white ethylene propylene dieneterpolymer EPDM roofing on the rear incident side. These panels were installed in part with grant money from the State of Nebraska Energy Office. Live output data is available on the MEI website.
What was a pivotal moment that impacted the project's direction?
I came on board once construction was already underway to oversee the documentation and certification processes. Originally, the project set out to earn LEED Gold certification, but after further analysis, we pursued additional credits that originally seemed unattainable.
Once I joined the project, I took a systematic approach of looking through the LEED checklist. After we were able to complete our energy model and achieve all 10 of the EA Credit 1 (Optimize Energy Performance) points, we were at a LEED point total in the upper range of Gold. At that point, pursuing Platinum looked like a possibility and was particularly exciting since at the time, there weren't any Platinum projects in Nebraska. I went through every credit that we had in the Maybe or No column and reconsidered if it was applicable to the project.
At this stage, we added six credits. SS Credits 1, 2, 5.1, and 5.2 (Site Selection, Development Density & Community Connectivity, and Site Development) were achieved simply through becoming familiar with the requirements and performing the necessary calculations and verification activities to confirm compliance. EA Credit 6 (Green Power) was added because it is relatively low-cost and the benefit from purchasing renewable energy credits (RECs) made perfect sense for our all-electric building; we currently offset 100% of our consumption through RECs. MR Credit 4.2 (Recycled Content) was achieved thanks to the general contractor's efforts to go above and beyond specified credit requirements and achieve 20% recycled content over the originally-prescribed 10%.
Last, IEQ Credit 2 (Increased Ventilation) was achievable based solely on the amount of makeup air we were required to bring in to maintain our desired building pressurization and exhaust rates. This example shows that knowledge of the rating system and the willingness to perform preliminary calculations to explore credit potential goes a long way toward demonstrating that design decisions meet LEED credit requirements. We are currently billed for electricity at a non-demand utility rate; to maintain this, we included a demand-limiting program into our BAS controls as a result of ongoing commissioning results and monthly demand monitoring. Limits of 50 kW for the summer and 80 kW for the winter were included so that if peak demand for the building exceeded those limits for approximately 15 minutes, select mechanical equipment would cycle off to decrease peak demand electrical consumption and avoid a change in required rate structure and additional cost. Since installing the 5.5-kW photovoltaic system on the roof, the demand limiting sequencing hasn't been required, though those controls are still in place.
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