Extruded Polyolefin Coatings for the Exterior of Steel Water Pipelines
|Publication Date:||17 January 2010|
This standard describes the materials, systems, and application requirements for shop-applied, extruded polyolefin coatings for the exterior of steel water pipe up to 144 in. (3,650 mm) diameter.
Extrusion types. This standard describes the following three types of coating-system applications:
Type A, crosshead-die extrusion, consists of an adhesive and an extruded polyolefin sheath. This system is limited to pipe diameters 1/ 2 in. through 36 in. (13 mm through 900 mm).
Type B, side extrusion, consists of an extruded adhesive and an extruded polyolefin sheath. This system is limited to pipe diameters 2 in. through 144 in. (50 mm through 3,650 mm).
Type C, side extrusion, consists of a liquid adhesive (primer) layer, extruded butyl rubber adhesive, and extruded polyolefin sheath. This system is limited to pipe diameters 2 in. through 144 in. (50 mm through 3,650 mm).
Maximum temperatures. AWWA steel pipe coating standards are written for and are based on the service temperature of potable water. Extruded polyolefin coatings have performed at higher temperatures. Consult the coating manufacturer for conditions and limitations.
Conditions not described in this standard. This section does not discuss the additional materials and procedures that may be required for difficult installation conditions, such as those encountered in the construction of submerged lines, casing pipe, river crossings, or lines that are in exceptionally rocky areas or where soil conditions are known to be severe. Under these conditions, additional layers of material, rockshields, such as, but not limited to, cement-mortar overcoat, specially prepared backfill, or other methods or materials may be necessary. The manufacturer should be consulted for specific recommendations when these conditions exist.
The purpose of this standard is to provide purchasers, manufacturers, and constructors with the minimum requirements for extruded polyolefin coatings for steel water pipe, including material, application, inspection, testing, marking, handling, and packaging requirements.