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.
n an open recess in a wall at the base of a chimney where a fire can be built. â 1 he laid a fire in the hearth and lit itâ. â 2 the hearth was black with the charcoal of many firesâ. â 3 they sat on the hearth and warmed themselves before the fireâ. â 4 driven from hearth and homeâ.