This procedure determines the percentage of ash in a submitted sample.
A sample of known weight is heated at 900°F for 4-6 hours in a furnace. After 4 hours, the sample is removed and quickly placed into a desiccator and cooled for 30 minutes. The sample boat is then weighed, placed back into the furnace for 30 minutes, cooled, and reweighed. This procedure is iterated until the sample weight remains constant. The percent of ash is calculated as (ash weight / sample weight) x 100%. The ash results from any inorganic species within the submitted sample that does not decompose during high temperature exposure.