AWS C2.20:2016 pdf download.Specification for Thermal Spraying Zinc Anodes on Steel Reinforced Concrete
1.1 Scope. This standard covers the application of zinc thermal spray coatings to steel reinforced concrete using arc and flame spray equipment. The application of the zinc on steel reinforced concrete requires an electrical connection to the steel reinforcement. Although other metals can also be applied with these methods and equipment, at this time the stan-dard only covers zinc and zinc alloys. This standard is formatted as an industrial process instruction: job description,safety, Pass/Fail Job Reference Standard, feedstock materials, equipment, a step-by-step process instruction for surface preparation, thermal spraying, quality control (QC), and a Job Control Record.
This standard is based on the literature, equipment, process developments, and industrial practices known at the time of publication. This standard does not cover the design standards or recommended practices for cathodic protection (CP) systems. The design of a CP system for reinforced concrete structures, including the connection of the zinc coating to the steel reinforcement, should be undertaken by an experienced and qualified Corrosion Engineer. Table 1 summarizes inspection, test methods, and acceptance criteria that shall be employed.
1.2 Units of Measure. This standard makes use of both U.S. Customary Units and the Intermational System of Units (SI). The latter are shown within brackets ([ ]) or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system must be used independently. For the purposes of determining conform-ance with this specification, an observed or calculated value shall be rounded to the nearest unit in the last right-hand place of figures used in expressing the limiting values in accordance with the rounding off method given in ASTM E29,Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications.
4.1.2 Specific Requirements
(1) Zinc feedstock shall meet the alloy composition requirements of ASTM B833 or AWS C2.25, with the additional requirement that the iron content shall not exceed 14 ppm.
(2) The minimum inspection and acceptance criteria for the zinc thermal spray coating includes:
(a) Surface preparation and thermal spray process qualification to include materials, equipment, and method.
(b) Production area and components to include specific inspection and measurement procedures, locations, and frequency.
(3) Thermal spray coating work requirements including: industrial process, which areas are to be sprayed (and not sprayed), thermal sprayed coating thickness, tensile bond strength, quality control (QC) steps, and the Job Control record (per 4.4).
(4) Pass/Fail Job Reference Standard for surface preparation finish (of the concrete or the concrete with exposed rebar, or both) and for the zinc thermal spray coatings.
(5) Thermal spray coating inspector qualification, designation, and authority on behalf of the purchaser.
(6) Thermal spray operator qualification and validation of operator qualification record.
(7) Schedule (thermal spray job start, duration, key events, maximum holding period, submittals, test panel, and completion).
(8) Concurrent work that may or will be ongoing during the thermal spray work on the job site that may cause(mutual) interference. Cite the procedural and remedial actions to be taken should interference occur. File Delay and Disruption reports as required.AWS C2.20 pdf download.