Section 10 — Material Requirements
Galvanized Coatings
IPE Engineering Practice IPE-EP-10-3-8
Document number: IPE-EP-10-3-8 · Section: 10 — Material Requirements
SCOPE
- This Practice covers the mandatory requirements governing the selection and application of hot–dipped zinc coatings.
- Any deviation to this Practice must be approved by the procedure in EP 1–1–3.
- An Asterisk (*) indicates that a decision by the Owner’s Engineer or Owner is required, or that additional information is furnished by the Purchaser.
2.0 REFERENCES
The latest edition of the following standards and publications are referred to herein.
STANDARDS AND PUBLICATIONS
| Engineering Practices |
|---|
| EP 1–1–3 Deviations to Engineering Practices |
| ASTM Standards |
| A123 Zinc (Hot–Galvanized) Coatings on Products Fabricated from Rolled, Pressed, and Forged Steel Shapes, Plates, Bars, and Strips A143 Safeguarding Against Embrittlement of Hot–Galvanized Structural Steel Products and Procedure for Detecting Embrittlement A153 Zinc Coating (Hot–Dip) On Iron and Steel Hardware A384 Safeguarding Against Warpage and Distortion During Hot–Dip Galvanizing of Steel Assemblies A385 Providing High–Quality Zinc Coatings (Hot–Dip) on Assembled Products A525 Sheet Steel, Zinc Coated (Galvanized) by the Hot–Dipped Process |
| Steel Structure Painting Council (SSPC) |
| SP 8 Pickling SP1 0 Near White Blast Cleaning |
DEFINITIONS
- Contractor – Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
- Inspector – A Refining Company appointed engineer or inspector.
- Manufacturer – The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
- Owner – Refining Company.
- Owner’s Engineer – A Refining Company appointed engineer.
- Purchaser – The party placing a direct purchase order. The purchaser is the Owner’s designated representative.
APPLICATION
- Cadmium plating is not permitted as a substitute for hot–dip galvanizing, and cadmium material shall not be used in coating structural members, bolts, washers, or nuts.
- (*) Electrodeposited coating or cold galvanize (zinc–rich paint) is not an acceptable substitute for hot–dip galvanizing, except where specified.
- High–strength bolting (>150,000 psi ultimate tensile strength) or bolting greater than one inch in diameter shall not be hot–dip galvanized but shall be coated by mechanical galvanizing or with an inorganic zinc–rich primer.
- All mill scale, rust, oil, welding residue, and other foreign matter shall be removed by the galvanizer before galvanizing. Carbon steel equipment shall be abrasive blast cleaned in accordance with SSPC–SP10. All other surfaces to be galvanized shall be pickled in accordance with SSPC–SP 8.
- Hot–dip galvanizing shall conform to ASTM A 143, A 384, and A 385. Materials shall be as follows:
- Structural steel shapes, plates, pipe, and bars per ASTM A 123.
- Hardware per ASTM A 153.
- Assembled steel products per ASTM A123.
- Lightweight steel shapes, strips, plates, pipe, etc., per ASTM A 525, G–90.
- Each component shall be completely submerged in the molten zinc. If multi–dipping is necessary for complete coverage, a procedure that gives the minimum amount of warping shall be used.
- Components of bolted assemblies shall be dipped separately with bolts removed.
- Each component shall be brushed or wiped after dipping to remove flux, icicles, dross, or any irregularity in the zinc coating.
INSPECTION
- Work found unacceptable shall be repaired prior to proceeding to the next step in the fabrication process.
- Acceptable coating weight and thickness shall be per Table 1.
6.0 TABLES
TABLE 1
COATING WEIGHT AND THICKNESS
| Steel Thickness (inch) | Oz/ft2 | Dry Film Thickness (mils) |
|---|---|---|
| 1/8 to 3/16 | 1.8 to 2.0 | 3.0 to 3.4 |
| 1/4 or greater | 2.0 to 2.3 | 3.4 to 3.9 |
NOTE:
In no case shall measurements taken be less than the minimum requirements listed in the above table
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