When you have a set of gas fireplace logs you will need to make sure you have proper venting. This is the gas if you have vented gas fireplace logs. The vented gas fireplace logs that are in fireplaces may need chimney pipe.
If you are using a masonry fireplace then you just need to make sure your chimney liner is in good working order. You can purchase chimney liners online at reputable retail stores. You can also purchase stove pipe online if you have a wood stove that needs venting.