In the first new stadium Q&A, we covered some of the basics about ethylene-tetraflorouethylene (ETFE), the plastic-like material that will be used to cover the south half of the facility’s roof. What is ETFE? How durable is it? How do you keep it clean? That was a nice primer to this week’s stadium installment, which will include some of your questions regarding the impact of the roof on the game day experience. Since several similar questions were submitted, we will pull one from each topic that should address many of your concerns.
Frank Riley – Are there any concerns regarding the potential for sun glare for players and fans with the clear roof?
Certainly the ETFE material on the roof’s south side, the glass wall/pivoting doors on the west side, and the openness throughout the new stadium will give fans the feeling of being outdoors while being in a climate-controlled environment. “Fritting,” a process used in glass preparation that leaves a pattern throughout the glass, will be used on the ETFE material to defuse some of the direct sunlight and radiant heat. This, combined with the orientation of the stadium, will minimize the impact on fans.
Along those same lines, many of you have asked whether fans will be hot inside the stadium. Again, the ETFE paired with a mechanical cooling system located at the top of the stadium that will push cold air down on to fans, will make for a comfortable experience for both the fans and the players.
John Larson – What can you do to get rid of shadowing on the field?
Shadowing will exist but we expect it to be very minimal. Along with the ETFE defusing sunlight, the steel support structure underneath the ETFE is much smaller and lighter than large trusses that span the length of the stadium, causing smaller shadows. HKS has prepared sun studies to better understand this issue. It is an important one for all parties, and we are confident shadows will not be an issue for players or fans.
Eric G. – Will any of the fans be under shadow considering only 60% of the roof is clear?
Yes, given that 40% of the roof will be a hard metal deck, a portion of the stadium seating will be within a shadow during day games.
William Smarts – The Dome is notoriously loud. Curious what the implications of the ETFE will be for crowd noise in the new stadium?
While the acoustic design is still underway, there certainly is a balance of ensuring that fans can hear the announcer and keeping this as one of the loudest stadiums in the NFL. First, the speakers throughout the stadium will be directed at the seats so fans will understand the spoken word. Nonetheless, the architects fully expect this to be a very loud stadium. The stadium is entirely enclosed; one half of the roof will be a hard metal deck. Furthermore, with the closest fans just 44 feet from the sideline, Vikings fans will be as close to the action as any NFL stadium. The reality is that fans truly make the difference in terms of noise, which is why stadiums like Mall of America Field, Green Bay’s Lambeau Field and Seattle’s CenturyLink Field are some of the toughest for visiting teams to have success.
Nathan Bork – Will snow/ice build up on the roof of the stadium?
Several characteristics of this roof are designed for the Minnesota climate. First, the slope of the stadium - rising from approximately 205 feet high in the east to approximately 270 feet in the west - will give the facility a unique ability to shed snow. Secondly, the translucent ETFE material will allow more sunlight and radiant heat through the roof, which combined with the natural rise of heat from inside the stadium will help melt the snow and ice. So where will all of that snow and ice go? Diverters will redirect it into gutters and collection basins located on the edges of the roof, keeping snow and ice from falling to the ground below.