430DD - 1
Conservation practice standards are reviewed periodically and updated if needed. To obtain
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the electronic Field Office Technical Guide.
NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
IRRIGATION WATER CONVEYANCE
HIGH-PRESSURE, UNDERGROUND, PLASTIC PIPELINE
A pipeline and appurtenances installed in an
To prevent erosion or loss of water quality or
damage to the land, to make possible proper
management of irrigation water, and to reduce
water conveyance losses.
CONDITIONS WHERE PRACTICE
This standard applies to underground
thermoplastic pipelines ranging from 1/2-inch to
27 inches in diameter that are closed to the
atmosphere and that are subject to internal
pressures of 80 lb/in2 or greater.
Pipelines can be planned and located to serve
as an integral part of an irrigation water
distribution or conveyance system designed to
facilitate the conservation use and management
of the soil and water resources on a farm or
group of farms.
Water supplies, water quality, and rates of
irrigation delivery for the area served by the
pipelines shall be sufficient to make irrigation
practical for the crops to be grown and the
irrigation water application method to be used.
General Criteria Applicable to All Purposes
Working Pressure and Flow Velocity. The
minimum acceptable class of pipe shall be that
having a pressure rating for water of 80 lb/in2.
The pipeline shall be designed to meet all
service requirements without an operating
pressure, including hydraulic transients, or static
pressure at any point greater than the pressure
rating of the pipe used at that point. As a safety
factor against surge or water hammer, the
working pressure should not exceed 72 percent
of the pressure rating of the pipe, nor should the
design flow velocity at sys