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.
A better choice would be using a 2 x 10 (50.8 x 254 mm) joist size. Using grade 1 lumber will provide more structural support with a smaller joist size. Calculations for choosing a floor joist size depend on the grade and type of the lumber, the length of the span, and the joist spacing. In addition, the weight of both live and dead loads must be considered. A dead load refers to the weight of all the materials involved in the building or deck.