(a) Heated Rooms. The chlorinators and sulfonators for a system using one-ton cylinders must be located indoors and maintained at a minimum room temperature of 65 degrees Fahrenheit.
(b) Outdoor Storage.
  (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 Gaseous Chlorine Disinfection and Sulfur Dioxide Dechlorination Systems). Calculations supporting system sizing must be included in the engineering report.
  (2) If a one-ton cylinder is stored outdoors, it must be kept in a storage structure that:
    (A) protects the cylinder from direct sunlight; and
    (B) allows safe removal and replacement of a cylinder.
  (3) A one-ton cylinder stored outdoors may be connected to heated pipes to prevent gas from liquefying in the transfer pipes.
(c) Heating Blankets.
  (1) A heating blanket on a one-ton chlorine gas cylinder is prohibited.
  (2) A heating blanket may only be placed on a sulfur dioxide cylinder to increase the operating temperature of the sulfur dioxide system. The design must specify the temperature a heating blanket may be set to maintain an adequate temperature inside a cylinder, based on the lowest consecutive seven-day average of the local daily low temperatures over the last ten years, as measured at the nearest National Oceanic and Atmospheric Administration's National Weather Service weather station with at least ten years of records.
  (3) The ambient temperature must be used to calculate a cylinder withdrawal rate in §217.273(a) of this title.
  (4) A heating blanket on a sulfur dioxide cylinder must include a mechanism that ensures that a blanket does not heat the cylinder surface above 100 degrees Fahrenheit. The engineering report must include a calculation that documents the setting for a heating blanket to maintain a sulfur dioxide cylinder surface temperature of less than 100 degrees Fahrenheit.
  (5) A cylinder with a heating blanket that is connected to a dechlorination system must have a downstream pressure-reducing valve.
  (6) A sulfur dioxide system must be capable of automatically deactivating a heating blanket if high pressure is detected in the cylinder or delivery system.

Source Note: The provisions of this §217.276 adopted to be effective August 28, 2008, 33 TexReg 6843; amended to be effective December 4, 2015, 40 TexReg 8254