924.05 TYPE OF PROTECTION REQUIRED.
   (a)    The type of protection required under paragraphs (a), (b) and (c) of Section 924.04 of these regulations shall depend on the degree of hazard which exists as follows:
      (1)    An approved air gap separation shall be installed where the public potable water system may be contaminated with substances that could cause a severe health hazard;
      (2)    An approved air gap separation or an approved reduced pressure principle backflow prevention device shall be installed where the public potable water system may be contaminated with a substance that could cause a system or health hazard.
      (3)    An approved air gap separation and/or an approved reduced pressure principal backflow prevention device and/or an approved double check valve assembly shall be installed where the public potable water system may be polluted with substances that could cause a pollutional hazard not dangerous to health.
   (b)    The type of protection required under paragraph (d) of Section 924.04 of these regulations shall be an approved air gap separation or an approved interchangeable connection.
   (c)    Where an auxiliary water system is used as a secondary source of water for a fire protection system the provisions of paragraph (a) for an approved air gap separation or an approved interchangeable connection may not be required providing all of the following conditions are met:
      (1)    At premises where the auxiliary water system may be contaminated with substances that could cause a system or health hazard, the public or consumer’s potable water system shall be protected against backflow or back siphonage by installation of an approved reduced pressure principle backflow prevention device.
      (2)    At all other premises, the public or consumer’s potable water system shall be protected against backflow or back siphonage by installation of either an approved reduced pressure principle backflow prevention device or an approved double check valve assembly.
      (3)    The public or consumer’s potable water system shall be the primary source of water for the fire protection system.
      (4)    The fire protection system shall be normally filled with water from the public or consumer’s potable water system.
      (5)   The water in the fire protection system shall be used for fire protection only, with no regular use of water. from the fire protection system downstream from the approved backflow prevention device.
      (6)    The water in the fire protection system shall contain no additives.
      (Ord. 110-1990. Passed 7-9-90.)