This standard describes the materials, systems, and application requirements for shop-applied extruded polyolefin coatings for the exterior of steel water pipes.
1.1.1 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. (50 mm) and larger.
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. (50 mm) and larger.
1.1.2 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.
1.1.3 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 coating material or a cement–mortar overcoat should be considered along with specially prepared backfill or other methods or materials to protect the pipe and coating. The manufacturer should be consulted for specific recommendations when these conditions exist.
1.1.4 Other substrates. Consult the coating manufacturer when this standard is referenced for substrates other than carbon steel, as the surface preparation methods, application methods, and performance data listed in this standard may not be applicable.
This standard or sections of this standard can be referenced in documents for purchasing and receiving steel water pipelines with extruded polyolefin coatings. This standard can be used as a guide for applying, inspecting, and testing extruded polyolefin coatings. The requirements of this standard apply when this document has been referenced and then only to extruded polyolefin coatings used for steel water pipelines.