Pellet Fuel Under the The Pellet Fuels Institute standards, there are two pellet fuel grades: premium and standard. The only difference between grades is in the inorganic ash content: premium should be less than 1%, and standard less than 3%. Premium is usually made of core wood (not bark). There are five fuel characteristics prescribed for both grades:
Bulk density per cubic foot (0.028 cubic meters) shall not be less than 40 pounds (18 kg) The diameter shall be 1/4 to 5/16 inch (635-794 mm) Maximum length shall be 1 and 1/2 inches (254-127 mm) Fines (dust) of not more than 0.5% by weight shall pass through a 1/8 inch (317.5 mm) screen Sodium content shall be less than 300 parts per million (ppm). Resource www.eere.energy.gov website
