NAC445A.6703. Pumping facilities: Discharge piping.

Except as otherwise justified by an engineer and approved by the Division or the appropriate district board of health, a supplier of water shall ensure that, with regard to the discharge piping of the public water system:

     1. A concentric reducer or eccentric reducer is installed at the pump, such that the diameter of the discharge pipe is at least 2 inches greater than that of the discharge of the pump.

     2. A fitting, which may consist of a spool or union, is installed on a discharge pipe to facilitate the removal of the pump. A gauge with a pet cock or ball valve must also be installed on the discharge pipe.

     3. A check valve or other suitable type of valve is installed just beyond the fitting required by subsection 2, to prevent the reversal of flow through the pump. On pumping installations of:

     (a) Low pressure, a swing check valve may be used.

     (b) High pressure, a silent check valve or automatic check valve, or another suitable valve, must be used. The engineer who designs such an installation shall seek to minimize the potential for water hammer.

     4. Another valve is installed just beyond the check valve required pursuant to subsection 3, to isolate the discharge and to provide for a positive shutdown of the system when repair is required.

     5. Isolation valves are not used for the control of flow or pressure and remain only in a fully open or a fully closed position. If the control of flow or pressure is desired, other valves must be installed.

     6. The piping is arranged in such a manner as to avoid high spots. An air and vacuum valve, which is piped to a drain, must be provided.

     7. The piping is rigidly supported and restrained in such a manner as to prevent movement.

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