When you have a vented gas log in your fireplace installed, it’s necessary to have the damper clamp open at all times. Having a damper clamp prevents a situation where gases are not vented out the fireplace. It’s a safety accessory in case the fireplace is turned on and is forgotten opening the damper.
A gas fireplace emulates a real fireplace, without the trouble of getting wood to burn. There are two gas fireplace types: vented and ventless. The vented type have a realistic look but loss most of the heat, instead the ventless one is very efficient because doesn’t need a chimney, losing the fireplace realistic look.
On which ever option you decide, the damper clamp is needed to keep the carbon monoxide out and avoid hazardous situations.