4.1 The purpose of this test method is to determine the amount of organic nitrogen present within a sample of electrical insulation paper or paperboard. Nitrogen content is used to determine if the paper or paperboard has been chemically treated to withstand higher than normal operating temperatures. Such a paper or paperboard is referred to in the industry as “thermally upgraded.” A paper or paperboard that is thermally upgraded can withstand higher operating temperatures and allow the electrical equipment to have a longer useful life span.

1.1 This test method covers the determination of nitrogenous organic materials in paper and paperboard, which typically are used to reduce the thermal degradation of the cellulose in the paper and paperboard.

1.2 The nitrogen determination by this method does not include the nitrogen in nitro compounds, nitrates, nitrites, azo, hydrazine, cyanide, or pyridine ring-type compounds, none of which are normally found in paper and paperboard. There is no known modification of the method that is applicable to all nitrogenous compounds.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.