Damper on conversion

**Tom Rees** · 10-17-2009, 04:35 PM

Bob, If you have a masonry fireplace that has been converted to gas logs, no pilot light (manual light) and no glass doors are you required to have a spacer permanently installed on damper so it can not close?

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**Bob Harper** · 10-18-2009, 10:32 AM

IRC G2453.1 Free Opening area of chimney dampers. Where an unlisted decorative appliance for installation in a vented fireplace is installed, the fireplace damper shall have a permanent free opening equal to or greater than specified in table G2453.1

G2432 Decorative Appliances for Installation in Fireplaces deals with vented gas logs listed to ANSI Z21.60, which have a flame safeguard device (pilot) and those listed to ANSI Z21.84, which do not have a safety pilot, shall be tested and installed to the mfrs. instructions. The listing requires language in those instructions to include the specified min. permanent net free damper opening.

Now, State codes such as Taxachoosetts may require the damper be completely removed or welded wide open in addition to the IRC requirements.

You described a match lit logset, which, if listed, would be to Z21.84. If not listed, it would fall back on the first section I quoted. You need to know what is accepted locally as many jurisdictions require listed appliances only with safety pilots.

The room must meet the volume or Makeup air requirements as set in G2407.5

The chimney and fireplace must be "working" and of noncombustible construction. I hate those combustible fireplaces.....

If you are in the process of converting the you should conduct a LeveL II inspection prior to conversion.

The listing of those logs requires a screen or glass enclosure FYI.

HTH,
Bob

Jay Walker · 01-11-2010, 08:08 PM

Bob Harper as most always is correct. I would add that the damper lock be put on the handle not the damper plate.

Jay Walker

Bob Fuhrmann · 06-22-2010, 03:21 PM

I inspected a house today that had two (1 up, 1 down) gas fireplaces. It didn't look like a conversion. It was not masonery. The logs were about 24" long. Both had screens and glass closures. Both also had a damper that could completely close off the chimney. Both had a pilot light that was lit 100% of the time. I queried the homeowner about it and he said that the contractor that serviced the chimney told him that the pilot light does not produce a great amount of gas and that he could shut the damper. My ? is, is it legal in Colorado to have a damper that could concievably be closed when the fire is on? When I tested the operation, that flame was 2 feet long and about 10 inches high when on high setting. Any help is appreciated. I have to submit this report soon.

**Tom Rees** · 06-22-2010, 04:10 PM

No!!!! Spacer is required.

**Bob Harper** · 06-22-2010, 05:33 PM

Locate the rating plate and see to which ANSI std the unit was tested to. If it was Z21.60 or Z21.84, those are vented sets that require the above min. permanent net free opening. If it is Z21.11.2, it is ventfree meaning if it passes a level II and meets the other requirements of the mfr. then the damper could remain closed. However, in either case, the glass doors would need to be fullly open during burning.

IF there is no rating plate, treat it like an unlisted logset and recommend replacement with a listed set pending passing a Level II inspection.

Yes Jay, the handle is the best place for those clamps IF you put it above the buckle. As long as it meet the *permanent* criteria as well as the net free opening. Usually, I blow out the damper, Rumfordize the Fp and install a ss cap w/ mesh (no top dampers with vented logs).

If you cannot be certain there is no rating plate, refer to a qualified hearth pro, which would probably include being NFI Gas certified.

HTH,