Hi, welcome to the exciting
Hi, welcome to the exciting world of glass fusing. You can get some ceiling tiles from any hardware store. They are not inflame-able – and easy to cut. Place one under your kiln and nail one to the wall behind your kiln. To my knowledge kilns keep the heat inside and I have not heard of any of them causing a fire. But using those ceiling tiles will give you peace of mind. As a beginner you might have gotten my book “Introduction to Glass Fusing” – let me know, if you have any further questions.