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.
All 90-degree turns should have bend supports. Do Know How Deep to Drill or Notch. With PEX tubing installation, drill to a maximum depth of 40 percent the depth of the wood on load bearing wood-and i-joists. Notches can go to a 25 percent depth. A non load bearing wood-or i-joist can be drilled to a maximum depth of 60 percent of the depth of the wood. Notches can go to 40 percent deep.