Non-Asbestos Gaskets

To the layperson the term non-asbestos might seem a little broad. After all it either is or it is not asbestos. Although this is true, it helps to understand where the term comes from.
For decades asbestos was used in gasket material. It provided a technological leap at the time when finding a material to handle over 200 F was challenging. Most gasketing prior to asbestos was natural rubber, plant fiber or a blend of both. The replacement of vegitable fibers (cotton, hemp, juete, flax, etc) with asbestos gave gaskets the ability to handle temperatures to 500 F and if quality asbestos was used above that.
Just in any product available there are many various of quality, as there are grades of asbestos. The basic determining factor for quality is the length of the fibers. Long spinning grade fibers from Canada, and African blue asbestos were the best grades, and were utlilized in the better grades of gasket material and cut gaskets.
The largest world wide producers of asbestos gaskets materials were, Johns Manville, Klinger, Garlock, and Durabla Manufacturing.
When replacement products were generated by Garlock, Klinger and Durabla Manufacturing, they were titled "Non-asbestos". So in our industry, products that are produced that use to contain asbestos, but no longer do are titled "Non-asbestos".