Roofing tar can be made either from Coal or Mineral Oil. These two types look very much alike, but have different chemical properties. Coal tar has a high concentration of graphite, asphaltenes, and Polynuclear Aromatic Hydrocarbons (PAH). It also contains other chemicals that are typically identified as hazardous. Such a difference in chemical composition between Coal and Oil Tar can be explained by the difference in production conditions. Temperature of a coal oven can vary from 1100°C to 1700°C. At that temperature, volatile organic compounds undergo a chain of chemical transformations that eventually lead to the formation of heavy PAH molecules. From there they form even heavier asphaltenes, and eventually graphite or soot. Oil Tar is distilled from natural oil at a much lower temperature of 450°C – 600°C, which leads to much lower concentrations of PAHs, and therefore, to a much safer product.
LCS Laboratory Inc offers a screening test for Coal Tar in Roofing Tar insulation by measuring the tar solubility in carbon disulfide. The procedure is based on ASTM methods D450 and D4. During the test, we extract tar from the roofing material and measure its solubility for compliance with the ASTM standard. If the sample property matches the Coal Tar solubility as defined in the ASTM standard, the tar is classified as Coal Tar. This test is used as a screening test for pure Coal Tar.
This test helps to minimize workers’ exposure to Coal Tar Pitch Volatiles during the removal of old roofing tar.
LCS Laboratory offers another related test for Coal Tar Pitch Volatiles in roofing tar by NIOSH 5515 method. This specific test targets a group of regulated polynuclear aromatic hydrocarbons (PAH).
To order either test, please send us a small sample piece (2″ by 2″) of the roofing material. Try to select pieces with an excessive amount of tar. Use the sample submission form to describe your samples and specify the test you require. Provide your contact information with an email address and a desirable turnaround time. Please email us to discuss your project.
