NAC445A.67235. Cross-connections and backflow: Installation of reduced pressure principle assembly.

Except as otherwise authorized by the Division or the appropriate district board of health, if a reduced pressure principle assembly is installed on a service connection:

     1. The reduced pressure principle assembly must be installed:

     (a) In a horizontal and level position, except that the reduced pressure principle assembly may be installed in a vertical position if the assembly has been:

          (1) Specifically designed for operation in that position; and

          (2) Tested and certified to be suitable for operation in that position by an approved backflow testing laboratory.

     (b) As closely as practicable to the service connection, on the opposite side of the service connection from the public water system.

     (c) Above ground and, to the extent possible, not less than 12 inches nor more than 36 inches above the finished grade, as measured from the bottom of the assembly.

     (d) At a site with adequate drainage, or with drain piping, for any fluid that is discharged when the assembly is activated.

     (e) In such a manner that no part of the assembly will be submerged during normal conditions of operation and weather.

     (f) In such a manner as to be readily accessible for maintenance and testing.

     2. The reduced pressure principle assembly must not be installed below grade, in any subsurface vault, or in any vault, chamber or pit where there is any potential that the relief valve could become submerged.

     3. The reduced pressure principle assembly must have a free-flowing drain with an air gap.

     4. There must be no type of outlet, tee, tap, take-off or connection to or from the service line between the service connection and the reduced pressure principle assembly.

     5. Expansion tanks or pressure relief valves must be provided as appropriate for the potential threat of water hammer and thermal expansion.

     6. The reduced pressure principle assembly may be installed indoors if the installation complies with subsections 1 to 5, inclusive, and has a clearance of:

     (a) At least 12 inches on top;

     (b) At least 24 inches on the side with test cocks; and

     (c) At least 12 inches on the other sides.

     (Added to NAC by Bd. of Health, eff. 2-20-97; A by Environmental Comm’n by R194-08, 10-27-2009)