Local gas fireplace installation for Ortega homes

Pipe inside a pipe

Direct-vent pipe is coaxial: an inner pipe carries exhaust out, and the space between it and the outer pipe carries fresh air in. The two streams run side by side all the way to the termination, which has openings for both. Because the incoming air surrounds the hot inner pipe, the outer wall stays cooler than a single-wall vent would, and that is part of why the listed clearances to framing are small. The pipe, its joints and its termination are one listed system from the vent maker the manual names, and parts from another system are not mixed in.

Reading the mantel chart

A combustible mantel above a gas fireplace follows a chart in the manual that pairs the mantel's depth with the minimum height above the opening. The deeper the shelf, the higher it has to sit. Trim that stands out from the facing beyond a small set distance is treated as a mantel under the chart, so a thick molding counts.

Some makers offer mantel packages already tested for their units. We mark the chart height on the framing so blocking goes in at the right level, and check the mantel you choose against it. The chart says where its measurements start, and we measure from the same point.

The volume rule for B-vent units

A B-vent fireplace takes its combustion air from the room, so the fuel gas code limits where it can go. In a bedroom, it is allowed only when the room has at least 50 cubic feet of volume for each 1,000 Btu per hour the unit burns, the code's standard method.

A small bedroom can fail that test with a modest unit. A direct-vent unit, which takes all its air from outside, is not held to the same volume rule when installed to its listing. We do the arithmetic from the room's measurements before recommending either. Ceiling height counts, so a tall room holds more volume than its floor area suggests.