A damper clamp is simple devices that prevents your fireplace damper from fully closing. By not fully closing, any residual natural gas or fumes from burning natural gas (such as carbon monoxide) can flow up and out the chimney.
Damper clamps are required by code
Damper clamps are required by code in fireplaces that have a gas line or gas feature. Though code never uses the words “damper clamp”, and it’s hard to follow. It starts with the California Energy Efficiency Standards, which says to look at the California Mechanical Code. The California Mechanical Code says to follow the NFPA (National Fire Protection Association).
Section 150(e) of the California Energy Efficiency Standards
When a gas log, log lighter, or decorative gas appliance is installed in a fireplace, the flue damper shall be blocked open if required by the manufacturer’s installation instructions or the California Mechanical Code.
The California Mechanical Code, 801.2 Venting of Gas Appliances
Low-heat and medium-heat gas appliances shall be vented in accordance with this chapter. Other gas appliances shall be vented in accordance with NFPA 211
NFPA 211
9.9.1 Manually operated dampers shall not be placed in chimneys, vents, or connectors of stoker-fired, liquid, or gas-burning appliances.
This a long-winded way of saying, a gas-burning fireplace should not have a damper. But since most gas-burning fireplaces do have a damper, a damper clamp is the best and easiest way to prevent a damper from closing.
So why is the damper clamp missing?
We find the damper clamp is missing in 90% of the gas fireplaces we inspect. Simply because most fireplaces were installed well before this became a requirement in the early 1990s.
However, for safety, it is highly recommended a damper clamp be installed on all fireplaces that have a natural gas line. Some gas utilities will red-tag and declare unsafe any fireplace that does not have a damper clamp.
Can I install a damper clamp?
Thankfully, a damper clamp tends to only cost around $10-$15. They are relatively easy to install.
Where do I NOT need a damper clamp?
There are two instances where a damper clamp is not needed.
- A fireplace that is wood burning only, with no gas line attached.
- A prefabricated gas only fireplaces that does not have a damper.
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