Requirements for Chlorine (Cl₂) Disinfection and Sulfur Dioxide (SO₂) Dechlorination Systems Using Gas Withdrawal from One-Ton Cylinders

1. (a) Heated Rooms. The chlorinators and sulfonators for a system using one-ton cylinders must be indoors and at a minimum temperature of 65 degrees Fahrenheit.

2. (b) Outdoor Storage.

   1. (1) If one-ton cylinders are stored outdoors, the system sizing must be done in accordance with §217.273(a) of this title (relating to Cylinder Requirements for Chlorine (Cl₂) Disinfection and Sulfur Dioxide (SO₂) Dechlorination Systems). Calculations supporting system sizing must be included in the report.

   2. (2) If a one-ton cylinder is stored outdoors, a storage structure must:

      1. (A) protect a cylinder from direct sunlight; and
      2. (B) allow safe removal and replacement of a cylinder.
   3. (3) A one-ton cylinder stored outdoors may have heated pipes to prevent gas from liquefying when a chemical enters a heated building or when gas cools in a pressure pipe.

3. (c) Heating Blankets.

   1. (1) A heating blanket on a one-ton Cl₂gas cylinder is prohibited.
   2. (2) A one-ton SO₂ cylinder may have a heating blanket to increase the operating temperature of an SO₂ system. A design must specify the temperature a heating blanket may be set to maintain an adequate temperature inside a cylinder, based on the lowest seven-day average of the local daily low temperatures over the last ten years.
   3. (3) The ambient temperature must be used to calculate a cylinder withdrawal rate in §217.273(a) of this title.
   4. (4) A heating blanket must include a mechanism to prevent heating a cylinder to more than 100 degrees F.
   5. (5) A dechlorination system must have a pressure-reducing valve downstream from the cylinders connected to the system and a high-pressure interlock to deactivate any heating blanket.

4. (d) Separation.

   1. (1) The housing of the SO₂ feed equipment for one-ton cylinders must be in a separate room from the chlorination feed equipment and cylinders.

   2. (2) A system with Cl₂ and SO₂one-ton cylinders must separate the feed equipment from the cylinders with a gas tight wall, except for the following exceptions:

      1. (A) One-ton SO₂ cylinders and Cl₂ cylinders may be stored in the same area if:

         1. (i) the cylinders are stored outdoors;
         2. (ii) an SO₂ outlet valve and a Cl₂outlet valve are separated by at least 10 feet; and
         3. (iii) the Cl₂ equipment and storage containers are marked differently than SO₂ equipment and storage containers.

      2. (B) SO₂ and Cl₂ chemical feed equipment may be stored in the same room if:

         1. (i) both systems are remote vacuum type;
         2. (ii) no pressure gas pipes are in the room;
         3. (iii) no cylinders are stored in the room; and
         4. (iv) the design ensures that Cl₂ and SO₂ cannot be mixed.

Source Note:The provisions of this §217.276 adopted to be effective August 28, 2008, 33 TexReg 6843.