Duraflame Crackleflame Firelogs Indoor & Outdoor. Duraflame Crackleflame Firelogs, provide all of the ambiance of a crackling wood fire without the mess or hassle of cleanup. They light fully in less than five minutes and burn for up to three hours in any type of open-hearth fireplace. You can use this log indoors in your living area or outdoors in your fire pit with confidence of a lasting burn and pleasant fire. Duraflame logs are a choice that you can feel good about as not one tree is cut down to make a Crackleflame Firelog.