An increased ACTH result can mean that a person has Cushing disease, Addison disease, or ectopic ACTH-producing tumors. A decreased ACTH result can be due to an adrenal tumor, steroid medication, or hypopituitarism.
All fabrics will burn, but some are more combustible than others. Untreated natural fibers such as cotton, linen and silk burn more readily than wool, which is more difficult to ignite and burns with a low flame velocity. The weight and weave of the fabric will affect how easily the material will ignite and burn. Fabrics with a tight weave - wool, modacrylic, 100 percent polyester and those that are flame-retardant treated are good choices.
I just came across something which I've never seen mentioned in any article dealing with fireplace & chimney clearances. I've wanted to wrap my (interior) chimney & the sides of the firebox in sheetrock, as I've seen in many pictures, but both the old & new codes wouldn't permit it. But this data sheet from USG lists sheetrock as a limited-combustible, and states that it would be allowed.