18 in. BLUEGRASS LIVING Birch Wood Vented Natural Gas Fireplace Log Set - 45,000 BTU, Match Light. The Birch Wood Log Set by BLUEGRASS LIVING recreates the look and feel of a real wood-burning hearth. This Vented Gas Log Set was molded from real wood providing a realistic appearance that incorporates detailed bark texture and accents. The U- Burner chassis design provides multiple rows of flames which brings you the most realistic flame patterns. Like a real wood burning fireplace, this log set requires a fully functional chimney with an open flue when in use. The glowing embers create the most illuminating beauty of a warm and classical ambiance. Material: Concrete.