The systemic circulation is the portion of the circulatory system is the network of veins, arteries and blood vessels that transports blood from heart, services the body's cells and then re-enters the heart, the Mayo Clinic noted. [Image Gallery: The BioDigital Human]
A southern pine (2) 2x12 beam can span 8 feet when supporting joists spanning a maximum of 14 feet, and it can cantilever 2 feet beyond the posts on each side. With the allowable cantilever of the joists, this beam would support a deck 12 feet by 17 1/2 feet.
Deck Floor Joist Spans - Part 1. Floor Joist Spans For Decks - 12 Joist Spacing. Part 2 - 16 & 24 Joist Spacing. If you are designing a deck, one of the calculations that you need is the size of the lumber required to span the distances between the deck supports or deck supports and wall.