1. Scope
1.1 This test method covers the determination of ash in the range 0.001–0.180 mass %, from distillate and residual fuels, gas turbine fuels, crude oils, lubricating oils, waxes, and other petroleum products, in which any ash-forming materials present are normally considered to be undesirable impurities or contaminants (Note 1). The test method is limited to petroleum products which are free from added ash-forming additives, including certain phosphorus compounds (Note 2).

NOTE 1 - In certain types of samples, all of the ash-forming metals are not retained quantitatively in the ash. This is particularly true of distillate oils, which require a special ash procedure in order to retain metals quantitatively.

NOTE 2 - This test method is not intended for the analysis of unused lubricating oils containing additives; for such samples use Test Method D874. Neither is it intended for the analysis of lubricating oils containing lead nor for used engine crank case oils.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. The preferred expression of the property is mass %.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents
2.1 ASTM Standards:
D874 Test Method for Sulfated Ash from Lubricating Oils and Additives
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4928 Test Methods for Water in Crude Oils by Coulometric Karl Fischer Titration
D6299 Practice for Applying Statistical Quality Assurance Techniques to Evaluate Analytical Measurement System Performance
D6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories

3. Summary of Test Method
3.1 The sample contained in a suitable vessel is ignited and allowed to burn until only ash and carbon remain. The carbonaceous residue is reduced to an ash by heating in a muffle furnace at 775°C, cooled and weighed.