Actually I think that the "squibs" just so happen to be precisely where vents to the outside were located on the mechanical floors. Funny that, eh?
The correct term is "louver". They are used for outdoor air intake, exhaust air, relief air, and combustion air.
These are usually specified by architects, but occasionally it's thrown in mechanical's court. Here are my two favorite manufacturers.
http://www.greenheck.com/products/louvers/
http://www.ruskin.com/louvers/