as long as可以作副词短语修饰“数词+名词”，表示“长达...”。我猜想你已经知道这种用法，只是对自己的理解没有信心。COCA中有很多类似的例句：

A cricket ball can go as fast as 100 miles per hour.
It can support a backdrop as heavy as 2,000 pounds and as tall as 30 feet.
The population is estimated to have grown to as much as 15 million in 2002.
"These are small groups - some as small as 10 or 50 people," says van Dijk.
You can buy a hose as short as 25 ft. or as long as 100 ft.
Biologists have suggested that zoos will need to maintain genetically viable populations of key endangered species for as long as 200 years.
Rolling on tracks and spanning a width as wide as 20 feet, this gantry allows the farmer to tend crops from above while lying on the carriage as it rolls across the gardening area.