The plywood furnished under this specification is of the quality necessary for boat and ship construction and for special applications on vital equipment for extreme environments. It is not intended for general construction where commercial exterior grades can be used. Distinguishing quality features under this specification provide: decay resistance, limitation of defects affecting strength and paint serviceability and ply construction necessary for marine exposure to insure necessary stiffness and resistance to ply delamination.

When it is known that plywood of classes 1, 2 or 3 are to be pressure preservative treated after manufacturing,³ the sapwood restriction is not required (see 3.2.2 and 6.2.1).