You will need refectory coating. It’s not hard to do or expensive. I recommend Kast-O-Lite 30 li. Soon as the wool reaches 1600f it changes to crystalbolite and releases a ton of tiny fibers that will cause major lung issues. You can’t see them, and they will coat everything, you, your clothes, everything around the forge, then those fibers get taken in the house for every one else to breathe. Not to mention the wool gets torn up easily and gets degraded by the flame. About $30 will make it safe and last much longer. Especially if you do any forge welds. Molten flux will eat wool up like cotton candy in the rain