This season's Super Bowl will be played on Yankee turf for the first time in the history of that scrimmage, north of the Mason-Dixon line in Pontiac, Mich.
What helps makes the geographical switch from the heart of Dixie possible is the Silverdome, a stadium enclosed by an inflatable fiberglass dome, which, no matter how you look at it, will be warmer than the subzero temperatures the Cincinnati Bengals had to offer their opposition a couple of weeks ago.
The Silverdome and other inflatable stadiums in Syracuse, Minneapolis, Vancouver and Indianapolis are being heralded by their manufacturers--Owens-Corning Fiberglas and Chemical Fabrics/Birdair--as the sole alternative available to cities faced with the prohibitively high costs of building conventional stadiums and convention centers.
"Basically, for long-span structures such as large stadiums, it is the most economical method of enclosing them," said Robert Mulligan of Owens-Corning's fabric structures division.
"Also, most communities are finding they really can't justify building a stadium unless they enclose it and use it for events that aren't held just during good weather--baseball, football, basketball, trade shows, rodeos, rock concerts, you name it. . . . It provides a large number of event days to pay for bonds the city is holding."
The inflatable domes, which are made of fiber glass covered by Teflon, also are described as costing less to build, heat and cool than a conventional stadium.
A study conducted by Geiger-Berger Associates--a New York-based consulting firm that has been involved with the development of most of the existing fabric roof structures--found that construction costs for the domes ranged from $15 to $18 a square foot compared with about $35 a square foot for a rigid dome.
The total cost of the Silverdome, including the purchase of the land, was $55 million. The cost of the fabric and cables required to build the dome was about $3.5 million, according to Mulligan.
Mulligan said most of the inflatable-dome stadiums have heating systems, although he pointed out that large audiences generate enough body heat to keep the stadiums sufficiently warm in winter.
In the summer months, cooling costs are reduced because the translucence of the domes makes lights unnecessary, he said.
Claims of energy efficiency are supported in another study by the Roanoke, Va., architectural firm V.V.K.R. Inc., conducted before the decision by Radford University to build an inflatable recreational facility. The study found that the dome could save the school $900,000 in energy costs over 20 years.
Industry enthusiasm is undaunted by the "deflation" of Chemical Fabrics' Minneapolis Metrodome after a heavy snowfall last November. The roof deflated after it apparently was punctured by a piece of metal, causing the fabric to drift down on the cable supports below it.
"At the Silverdome, in an inflated condition, the center of the dome is 205 feet above the floor," Mulligan said. "In a deflated condition, it is 105 feet above the floor.
"In Pontiac, they played two football games while the dome was being constructed and the ball never hit the roof. Even if the stadium were full and the roof deflated for any reason, there would be no hazard to the occupants because it would be well above their heads."
The domes are inflated by air pressure generated from a number of large, industrial-size fans. The Silverdome has 26 fans. Sixteen of them are in operation when the stadium is filled to its capacity of 80,000, while only four are run when the hall is empty.