By Matthew from Bloomfield Hills, MI on November 10, 2013
Can you please tell me the exact size of the standoff? I have a log cabin, so although the exterior is not vinyl it technically is combustible. Would I need this? I would be using it as a part of my venting system for an FMI direct vent fireplace, with a horizontal square termination cap. Also what is the difference between a horizontal square and horizontal round termination cap?
By Collin C. - NFI Master Hearth Professional on November 11, 2013
Answer:Even though your cabin is log construction, a siding standoff would not be used for your application. This is only required for applications with vinyl or stucco exterior, as both materials contain polymers that have a low melting point and are easily damaged by the exhaust released from a direct vent appliance. The exhaust will not be hot enough to damage wood.
The round termination is the standard option and works well for application where wind is not an issue. For short vent runs or high wind applications, the square termination should be used. It has an internal baffle and louvers that are designed to prevent wind related drafting issues. It is often the standard choice, as it can prevent any possible issues from ever occurring.