The latest iteration of the ASTM heating oil specification, D396-15a, will be published soon, according to ASTM. In 2008, ASTM passed a measure allowing up to 5 percent biodiesel in the D396 fuel oil standard.
D396-15a adds parameters for stability and allows a slightly higher distillation temperature for the blends, the same changes included in the D7467 specification passed by ASTM in 2008 for on- and off-road diesel fuel blended with 6 to 20 percent biodiesel.
Read more: http://www.biodieselmagazine.com/articles/341153/astm-releases-b20-heating-oil-specifications