[James Steele]

Originally Posted by Team Sheep Can someone explain to me the purpose of an inflated roof like that of the Metrodome and the old RCA Dome? It don't really get the reasons for it, it just seems potentially risky.

Advantages and disadvantages

There are some advantages and disadvantages as compared to conventional buildings of similar size and application.
Advantages:

• Considerably lower initial cost than conventional buildings
• Lower operating costs due to simplicity of design (wholly air-supported structures only)
• Easy and quick to set up, dismantle, and relocate (wholly air-supported structures only)
• Unobstructed open interior space, since there is no need for columns
• Able to cover almost any project
• Custom fabric colors and sizes, including translucent fabric, allowing natural sunlight in

Disadvantages:

• Continuous operation of fans to maintain pressure, often requiring redundancy or emergency power supply.
• Dome collapses when pressure lost or fabric compromised
• Cannot reach the insulation values of hard-walled structures, increasing heating/cooling costs
• Limited load-carrying capacity
• Conventional buildings have longer lifespan

http://en.wikipedia.org/wiki/Air-supported_structure