Gas log insert damper

:shock: What is the code requirement for the damper for a gas log insert? Does code require that the damper only be allowed to close 90%.

Gas log damper should be wired permanently open.

Removing it is acceptable also.

I like to see them removed, if accessible.

A damper-stopper is the norm, and perfectly acceptable. One comes with every gas log set and its installation is required by the manufacturer of the gas-log set.

What is the code reference number for that guideline (damper opened/stopper)?
I have skimmed various areas of the IRC, but have been unsuccessful in finding it.


Better still take the gas log out and shut the gas line off, and make the damper operable, its an energy waster!

A non-permanant inflatable damper can be used with a gas log, if heat loss through the chimney flue is an issue. The inflatable type damper pops and falls out if the gas log owner lights the gas log without removing it first.

Here is a Q&A article about it.

I will assume we are talking about a “vented” gas log set here. There are also unvented gas log sets available and it is important to know which kind is installed before making a blanket statement in a report. On many unvented gas log sets and fireplaces, there is not any kind of flue even available nor a chimney. I would suspect these are not allowed in some locations but are in other regions of the country. As a precautionary note I always include statements regarding Carbon Monoxide alarms necessary whenever any kind of open flame or fossil fuels are being used in a home.

Agree. I just had a home with two fireplaces, both unvented gas logs, no flue, remote control, etc. These typically have Carbon Monoxide detector included with the set which will shut them off. I still recommend installing carbon monoxide alarms if the home does not have them.

International fuel gas code 634.1 chimney free opening area of dampers theres a table to go by

I hope I am comparing apples to apples here. I see the 634.1 in the 2003 version of the International Fuel Gas Code. But in this Alaska Fuel Gas code ammedment it says at the bottom of the last page (Page 16) to delete 634 and 634.1 in its entirety.

Does that mean this Alaska ammendment changed that 634 and 634.1 code but only in Alaska? Could someone clarify?


Most local building codes reflect national codes but, local building codes do supersede all National codes unless the National code was revised.