For external home fire situations, I saw a news segment on a product called Barricade. The concept was a fireman who watched a wet diaper remain untouched in a trash fire.

The product costs about $300 to spray onto a whole house. It creates a barrier that hold tremendous water for up to 18 hours. The test they showed was a sheet of plywood half covered in this product and set on fire. After they extinguished the fire, the untreated side was black, charred and smoking. The Barricade side was cool to the touch and looked new.

Standard disclaimer but looked interesting. Guess you can buy online but working with Home Depot to sell.