scope:

This standard describes the materials and application of viscoelastic coating systems to the exterior of steel water pipe and fittings to be used for underground and underwater service. For the purposes of this standard, the coating system has a viscoelastic compound as a corrosion-prevention layer that shall be based on either polyisobutene (PIB) or amorphous polyalphaolefin (APAO). Viscoelastic coatings systems conforming to this standard may be field-applied to repair or rehabilitate pipe and fittings, shop-applied to fittings, or used as a joint coating for pipe and fittings protected with organic coatings, such as those described in ANSI/AWWA C203, ANSI/AWWA C205, ANSI/AWWA C209, ANSI/AWWA C210, ANSI/AWWA C213, ANSI/AWWA C214, ANSI/AWWA C215, ANSI/AWWA C216, ANSI/AWWA C222, ANSI/AWWA C224, ANSI/AWWA C225, and ANSI/AWWA C229.

For normal construction considerations, viscoelastic coating systems are either applied as a two-layer system consisting of (1) a corrosion-prevention inner layer, and (2) a mechanical outer layer; or applied as a one-layer system where the corrosion-prevention inner layer and the mechanical outer layer are bonded together and applied as a single layer.

This standard establishes the minimum requirements for viscoelastic coating systems used on the exterior of steel water pipelines in the potable-water supply industry, and exceptions to this standard should be specified by the manufacturer or purchaser. Continuous monitoring of application procedures for the coating systems shall be performed by the applicator.

Maximum temperatures.

AWWA pipe coating standards are written for and based on the service temperature of potable water. Viscoelastic coating systems have performed at higher temperatures. Consult the coating manufacturer for conditions and limitations.

Conditions not described in this standard.

This standard does not describe the additional mechanical protective materials and procedures that may be required for difficult conditions, such as those encountered in rocky areas or where soil conditions are known to be severe, in construction of underwater lines, casing pipe, and river crossings. Also, it is not intended to describe conditions of extended exposure aboveground after application. When extended periods of aboveground exposure are required, the coating manufacturer should be consulted for specific recommendations.

Other substrates.

Consult the coating manufacturer when this standard is referenced for substrates other than carbon steel. The surface preparation methods, application methods, and performance data listed in this standard may not be applicable.

Purpose

The purpose of this standard is to provide minimum performance requirements for viscoelastic coating systems for the exterior of steel water pipelines, including system components, application, inspection, testing, marking, and packaging requirements.