As for safe for home use, as long as you were a dust mask when cutting it, it's safe to handle. Now, if you are talking about putting it in an area that the airflow is going to be in contact with it, you would probably need to do something to isolate it from the air flow. The stuff is not very durable. When used in forges etc, with it's exposed they coat with a protective coating
Probably the foil backed insulation they use in ovens would be more suited. I think it insulates a lot better also.
Now as for insulating, a one inch layer is probably no going to make the outside safe to touch.
I have a large brick over with a one inch layer sandwiched between a piece of SS and the back of an aluminum door I put on when baking in it and, you don't won't to touch that door.
Now, I run 4" Ceramic Fiber Blanket 2600F 8# High Temp Thermal Insulation on the sides of the oven and five inches on the dome and it never gets over 90 degrees on the sides and 120 in the center of the dome, even with it being fired all day. That's with an internal dome temp of over 1100 degrees when cooking pizza's.