DETERMINATION OF CARBON BLACK CONTENT
(TS ISO 6964)

It is aimed to determine the amount of carbon in the structure in order to ensure the resistance of the pipe and fittings to UV rays. The test is carried out by burning in a heat oven at high temperature with pure nitrogen gas. A quantity (about 1 gram) of the raw material, pipe, or insert described is pyrolyzed (decomposed by temperature effect) under a nitrogen gas stream at 550 °C for 45 minutes and calcined (burning to powder) at 900 °C. The amount of carbon black are calculated from the difference in mass before and after from calcination and pyrolysis. The criterion for PE pipe and fittings is 2-2,5% by mass. The amount of carbon black between 2 and 2.5% by weight provides the most effective protection against UV radiation in pipelines exposed to sunlight in overground applications.