Designing a winning sports venue
CSE: How have the characteristics of such projects changed in recent years, and what should engineers expect to see in the near future?
Evans: Venues are increasing in size to accommodate larger occupant loads. Smoke management systems are being incorporated into the facilities to allow these larger occupant loads and limit aisle width increases (Smoke Protected Assembly Seating). Over the past 10 to 15 years, theaters on the Las Vegas Strip have been constructed so the performance can surround the audience. Although this provides a more intimate experience, it makes it difficult to incorporate the level of protection provided by a proscenium. This inevitably requires using the alternate methods and materials provisions of the International Building Code to develop a performance-based fire protection approach to provide equivalency.
Sawarynski: We see new venues designed for specific leagues, such as Major League Soccer; specific uses, such as the College World Series Stadium in Omaha; and for mixed entertainment when no team is in place, such as Sprint Center in Kansas City. While venues are being built for diverse reasons, the common theme is that they are programmed and designed as multi-use venues. Today’s cost models require these venues be flexible and serve many purposes. Engineers need to understand how these varying uses affect system sizing, part load operation, and flexibility for growth and change.
Atienza: Sporting facilities like stadiums and arenas are very challenging when it comes to energy efficiency. These facilities have a very large carbon footprint that requires tons of steel and concrete to construct. These types of facilities require very large quantities of water to serve restrooms, showers, concessions stands, landscaping, and playing fields. Recreational facilities generally require large volumes of spaces to house indoor swimming pools and basketball courts, which results in very large heating and cooling loads. U.S. Green Building Council’s LEED is changing the way we think about how our buildings should be designed, constructed, maintained, and operated across the world. LEED addresses the entire building lifecycle, recognizing the latest technology in building strategies. State regulations and owner requirements, along with the sensitivity of the environment, have required the design industry to respond accordingly. Architects and engineers have not avoided the challenges sporting facilities pose. Improvements in building technology have allowed the design industry to reduce energy consumption for these types of facilities, while reducing the impact on the environment with the use of recycled materials. Finally, large sporting facilities are beginning to use alternative fuel sources such as solar thermal water heating systems. Rainwater re-claim systems are being designed to recycle treated wastewater back into the facility for flushing water closets and urinals. The large water demand created by these types of sporting facilities allows rainwater harvesting systems to have a much shorter payback period.
CSE: How does engineering systems in large-scale sports and entertainment arenas differ from working on smaller venues?
Atienza: Large-scale sporting venues consume large amounts of water, especially at halftime. Domestic water booster pumps and associated pipe sizing are increased in size to handle the peak water demands. To counter this high water demand, low-consumption plumbing fixtures, along with electronic faucets and flush valves, are specified for the restrooms. Technology is now available to capture the energy from running water to recharge the batteries serving the electronic faucets. Particular attention must be paid to the plumbing fixture counts with the proper balance between men’s and women’s facilities. Newer plumbing codes now require two women’s water closets per every men’s water closet. Lines outside of women’s restrooms are now becoming a rarity.
Evans: These venues accommodate large occupant loads that require designers to ensure a safe environment. Because large open areas do not provide fire-resistive separations, other means of protection are necessary. Automatic sprinklers are invariably installed, but in high-bay spaces there is little assurance they will perform as intended. Mechanical smoke management systems are common, but have their own design constrains and limitations that must be well understood. A well-designed egress system is a must.
Sawarynski: Wow, I could take this answer in so many directions. Clearly they require unique understanding of process; they require design/construction teams made up of many experts with countless ideas, experiences, and opinions; and they typically have cost and schedule controls that really drive early decision making in a way most projects do not experience.
CSE: What type of modeling tools do you use?
Mack: The Nebraska Athletic Performance Lab (APL) architecture and engineering BIM solution was modeled in Autodesk Revit Architecture 2012 and Revit MEP 2012. The challenge to the design team was that the APL was a fit-out within a much larger expansion project at Nebraska’s Memorial Stadium. The stadium expansion was under construction when the APL project was in design. The university provided DLR Group with the stadium expansion’s Revit model, and we integrated the stadium expansion's architectural, structural, and mechanical, electrical, and plumbing (MEP) models as well as the APL architectural fit-out walls and ceilings. Due to the rapid construction schedule, the contractor was required to produce 3-D coordination drawings to advance the construction as rapidly and as smoothly as possible. The contractor team used Autodesk Navisworks collision detection to predict any potential clashes and made minor adjustments as necessary. Presentation renderings were produced in Revit for design analysis purposes as well as to anticipate and reflect what the finished space would look like. The lighting illuminance target on the Dynamic Level was 100 fc to mimic conditions the athletes would experience during games. Dimmable LED fixtures were chosen to save energy at times when athletes were not undergoing testing. The lighting illuminance was modeled using AGI 32 software with very basic renderings to review glare conditions due to the high illuminance requirement combined with low fixture mounting heights required due to the existing structure.
Sawarynski: Our modeling tools include various energy modeling platforms, certainly Revit for building design/BIM, and computational fluid dynamics (CFD) software to help look at system performance in what can be a very challenging building type to apply conventional HVAC design approaches.
Evans: The primary computer modeling that I review is used to design smoke management system(s). These days, most designers use Fire Dynamics Simulator (FDS) for large open facilities, which is a CFD model available as a free download from the NIST website. Relatively simple algebraic equations are available, but typically provide more conservative results than the more sophisticated models. In order to save on construction costs, design teams seem to prefer the computer analyses.
Atienza: At Interface Engineering, our modeling software is Autodesk Revit. Using Revit, we can build models that link with architectural and structural models, resulting in very powerful collaboration during the design process. We also leverage the model using analytical software for lighting, energy, and HVAC design, such as AGI, IESVE, eQUEST, and Green Building Studio. For clash detection, we use Autodesk Navisworks Manage.
CSE: Please explain some of the general differences between retrofitting an existing arena and working on a brand-new structure.
Evans: It’s always easier to coordinate and install the fire protection aspects for a new building rather than retrofit an existing facility. One example that comes to mind is supply air for the smoke control system. As makeup for the air being exhausted, the supply air must be provided below the design smoke layer and at a low velocity (not exceeding 200 ft/min at the plume).
Sawarynski: Retrofits typically focus on upgrades to and replacements of failed systems and modifications to accommodate architectural changes to existing areas. Applying today’s approaches to revenue-generating spaces (suites, clubs, etc.) in existing arenas can lead to some significant challenges for engineers. These challenges typically include dealing with complicated and strained space planning, sequencing if arenas remain online, and adapting often archaic systems to meet new codes. We saw perhaps the most challenging example of this on the planet when we worked on the renovation of Madison Square Garden. New arenas don’t have these same issues, but they have their own set of unique variables and can be just as challenging.
CSE: What clash detection challenges have you overcome? Discuss interstitial space coordination at one of these projects.
Mack: For the Nebraska Athletic Performance Lab, the interstitial space coordination was key to meeting the university’s goals, especially on the Dynamic Level where the athletes are tested. The Dynamic Level has a floor-to-floor height of 14 ft with structural depths that varied from 20 to 38 in. in depth. In addition to the structure, a 6-in. raised floor was required for placement of the force plates used for athletic testing. There was a requirement to maintain 11 ft clearance in the hitting cage area to allow enough space for baseball, softball, and golf. All other areas on the Dynamic Level were to be maintained as physically high as possible. With a limited floor-to-floor height, it was understood the MEP systems would be exposed so aesthetics was as important as and functionality. Galvanized steel supply and return ductwork was extended from the duct chase into the stadium concourse where the majority of the variable air volume (VAV) boxes that serve the Dynamic Level are located. Fabric ductwork was then extended from the VAV boxes into the Dynamic space. The fabric ductwork was specified with an internal wire frame to maintain the fabric duct round and taut at all times, with or without air pressure. The fabric ductwork was more cost-effective than an all-metallic duct system, did not require insulation, and was available in colors that were compatible with the space architecture.
Atienza: The biggest hurdle we have overcome is in educating our users about the importance of producing a clash-free model through the following principles: watch for other work to avoid creating clashes, check for clashes often, and fix clashes before you add more content to the model. It sounds simple, but it’s very easy to focus only on your own design when deadlines are approaching. If you wait until the end of the project to check for clashes, you will have an unmanageable amount of problems to fix.
Sawarynski: In any arena design there are significant clash detection challenges. Sloped structures, seating bowls with limited structural dead load capacity, and a plethora of unique “high-end” spaces means we are constantly dealing with design changes, unique one-off spaces, and minimal space “wasted” on allocation to MEP systems. Interstitial coordination can be very rigorous, especially when an arena is on a fast-track construction schedule. As MEP engineers, we are often trying coordinate with structural systems designed and released long before interior spaces are defined and MEP systems can be designed in detail for coordination.