The vacuum tube in a CRT can implode if it is broken or punctured. The surrounding air will rush violently into the unsealed vacuum in the CRT, spraying broken glass in every direction. Color CRTs may contain mercury or other potentially toxic materials.
Instructions. Build a hearth for a fireplace that is 16 inches deep, according to This Old House writer Harry Sawyers. This is the standard requirement for municipalities and homeowner associations. The hearth should also extend a minimum of eight inches on either side of the fireplace.
Specs: 1  Dimensions: 50.4â³ wide x 5.5â³ deep x 21.65â³ tall. 2  1,500 watts, heats up to 400 square feet. 3  Power consumption: 2.5W per hour. 4  3 heat settings, including only flame effect. 5  If mounting under a TV, fireplace needs a minimum of 36â³ clearance. 6  Comes with remote control and timer.