Each hot-water riser throughout the building shall be accompanied by a corresponding circulation pipe, |-inch in diameter, which shall be connected to the hot-water riser by means of a return bend on the top floor of the building. The hot-water riser, also the circulation riser, shall be supported only at the second floor of the building, so the ends will be free to expand up and down.
The contractor shall provide and set up where shown on the plans, one steel hot-water tank 48 inches in diameter and 8 feet high, made of 5/16-inch steel plates double riveted, the seams calked perfectly water tight, and guaranteed to withstand a pressure of 300 pounds per square inch. The tank shall be connected by means of a 2 1/2-inch flow and return pipe to a cast-iron Ideal, Yale or Sunray water heater containing 6 square feet of grate surface and having a smoke flue of 10 inches diameter. The tank shall stand upright alongside the heater and both shall rest on a cement base especially provided for the purpose. Cover the hot-water tank with 1 1/4-inches of asbestos plaster smoothly troweled on over a band of expanded metal.