Foam to be used in OBP fuel tanks, perfect if you are manufacturing your own tank. Once installed inside the fuel tank, the reticulated polyurethane foam essentially functions as a three dimensional fire screen. The foam is 98% void and only reduces fuel volume by 4% and adds only a negligible amount of net weight to the fuel tank. Baffle Foam is used in fuel tanks to reduce slosh, aid pick up and suppress explosion.