Was asbestos added to FG? I seriously doubt it
Was asbestos added to FG? I seriously doubt it. What would be gained? Asbestos in solid form, sheets, tapes, and wraps is fireproof, and a good thermal insulator. To add a natural solid insulation to a manufactured fibrous insulation is nothing any of the FG would have been interested. Fiberglass is common to use R-3 per inch, atFiberglass Tape Suppliers 1 pound per cubic foot density. Asbestos fibers. Take at least two pounds per cubic foot to reach that. Prior to the Arab Oil Embargo, 1974, there was no demand for more R-Value per inch. After that they concentrated on changing ; they worked with density to improve the R- Value of their product. Some types of fiberglass fibers are rated to achieve R-15 in a 2x4 wall, instead of R-13.
Was Fiberglass added to asbestos? Sort of. A fiberglass tapeChina Ceramic Fiber Rope Manufacturers was very common to wrap asbestos around pipes and ductwork. The a resin was added to make sure the asbestos stayed in place. Very similar process to repairing a hole with fiberglass. If fibers were added to the asbestos it would be more for strength, not thermal insulation value.