AskCodeMan

Just by looking at a prefab fireplace how can one tell if the already installed fireplace is rated for gas only or can burn solid fuel? Assume no available literature or record of permit.
Do hybrid fireplaces have any distinguishing features that would separate them from gas only fireplaces?
Is there a resource, website or other that would be helpful in determining this.

David

David,

I'm not sure, I'll see if I can contact someone who probably has the answer.

Jerry

The earliest factory built fireplaces were designed for woodburning only. Later, the mfrs. added conduits to each side so plumbers would not be tempted to hack holes in the sides of the fireplaces, which is a fire hazard. A typical woodburner has a minimum 8" diameter flue. The chimney would be triple walled air cooled, double walled air cooled, or solid packed chimney and all would have a special termination listed for use with that make and model fireplace only.

As vented gas logs became more common, the knockouts came cast in the side refractory panels that lined up with the conduits. In1987, Ron Shimek of Heat & Glo invented the double walled gas direct vent fireplace. This allowed sidewall venting and sealed combustion in tightly constructed homes. These fireplaces are often recognized by the sealed glass on the front and the horizontal sidewall termination. However, there are straight up dedicated gas fireplaces that vent vertically only using type 'B' vent. These can be identified by the ANSI Z21.50 on the rating plate, even though early direct vents carried this listing too. Later, the direct vents could be listed under ANSI Z21.88, which is a 'vented room heater' listing as opposed to the 'decorative appliance Z21.50 listing.

Now, there are also ventfree gas logs and fireplaces. You may find these installed into woodburning factory built fireplaces. Be careful to read the rating plate and listed instructions as many fireplaces specify they can NOT have ventfree logs installed as in these fireplaces, they constitute an extreme fire hazards. There are also dedicated ventfree only factory built fireplaces listed to ANSI Z21.91 The logsets themselves are listed to Z21.11.2b

All factory built fireplaces came with a metal rating plate. You may have to search around but its there. It may not be legible but its there. If you can read the listing standard, that will be a start but again, the ultimate answer lies with the codes.

Hope this helps.