Metrodome Roof - Constant Inflation Since 1982?

I was just reading this article about Minnesota’s Metrodome roof being deflated for the last time before the stadium is demolished to make room for a new stadium. What caught my eye were these statements:

Officials from the Minnesota Sports Facilities Authority opened the stadium’s relief vents to begin the deflation at 7:15 a.m. Saturday in downtown Minneapolis. Fans providing the air that supports the roof were turned off.

and

The muffin-shaped dome opened in 1982 and was once a focal point of Minnesota professional sports.

Wait, they have had to run fans non-stop since 1982 to keep the roof inflated? Even when there is no event going on there? Wow, the utility bill must have been staggering - how inefficient is that?

You must have forgotten about the collapse of the roof in 2010.

http://www.youtube.com/watch?v=AAyLX2hY7E0

Even during that collapse, is it not possible that the fans were still running? The roof didn’t collapse because they turned the fans off.

I’m embarrassed how long it took me to parse this sentence correctly. Since it was a story about a sports complex my brain immediately latched on to the wrong meaning of “fans” and was surprisingly resistant to letting go.
But now I do have an image of Vikings fans blowing hard at the ceiling for 32 years.

Sounds like they are pretty much gone now.

IIRC, there were 5 times the roof was deflated, including the most recent collapse in 2010. I’d assume the fans were turned off during that since they weren’t being used.

The metrodome was used in a lot of different ways. The University of Minnesota had games there (until their new stadium was built), the Twins and Vikings both shared the stadium. Then there was the Rollerdome which allowed rollerskating on the off days when nothing was going on along the outside of two levels. And the random concert or home improvement show there too.

If the monthly electricity bill is only $60k, then that’s probably dwarfed by other operating expenses. Heck, just the janitorial crew probably costs more than that. And it’s not like the electric bill is entirely for the inflation fans, either: That’s also covering the lighting, air conditioning in some sections, media technology, etc.

Interesting article - thanks!

Chronos - no doubt the monthly cost for this is relatively small, as you point out. But a lot of those other costs are there only when the facility is actively used, but the electricity bill appears to be constant, even if there are no events, or tennants.

I guess these designs are from another time when energy costs were not seen as a serious concern.

Anecdote about the doors at the Metrodome:

In order to keep the air pressure higher inside the dome (and, thus, keep the dome inflated), the Metrodome used revolving doors for all of the exits.

The Metrodome also had traditional hinged doors, but those were designated for emergency use only, as opening those would lead to an equalization of the air pressure inside and outside.

In the mid-80s, I was dating a girl who was from suburban St. Paul. One summer, when I was up there, visiting her and her family, we went to a Twins game at the Metrodome. As we were leaving, we saw a kid (who was inside the facility) make a break for one of the “regular” doors, being pursued by a security guard. The kid made it to the door, and pushed it open. He was then pushed out the door by a substantial gust of wind (laughing the whole time). The security guard then struggled to get the door closed again. I’d have to guess that this blast of wind was well-known, and kids kept trying to pull off the stunt.

I went to a concert at B.C. Place once, which had the same type of inflated roof. I went in through a revolving door and didn’t think much of it. One the way out, there were several regular doors propped fully open. Got a nice tailwind on the way through. Just a few feet away, though, everything felt normal.

I don’t think they were emergence doors. I just got the impression they opened them after the event because everyone is leaving at the same time.

they have to too. if they stop blowing then the ceiling sinks and get punctured by horns.