2023 HDG Specification Updates
The AGA participates in standards organizations such as ASTM, ANSI, AASHTO, AISC, NSBA, AMPP, CSA, IEEE, and more to represent the interests of the HDG industry and serve as a technical resource. Provided below is a summary of industry standards activity in 2023 including recently published changes. To be the first to know about specification updates or to get involved on the front lines, any AGA member, specifier, or party of general interest can join the effort. If you have any questions about these specification updates or would like to get involved, please contact the AGA Technical Department.
Note: AGA cannot distribute copies of ASTM standards to members or their customers for information or use. Most products produced by a standards organization such as ASTM, ISO, etc. are copyrighted and protected by U.S. and International law. When you download an individual standard or a standards volume, typically there are restrictions on how you can use, share, and distribute the file and its contents. Learn more from AGA about revisions & proper use of galvanizing standards.
ASTM A153/A153M, Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware
A revision to Note 6 was published in 2023 to address the acceptance of parts susceptible to residual buildup of zinc (e.g. 90 degree elbows or tees). This is relevant for projects where the number of test articles for inspection is very small compared to the lot size. The change informs a specifier that, statistically speaking, it is possible to run into a few unusable parts or outliers even if the lot passes and galvanizing best practices are followed.
NOTE 6—Since this specification is applicable to items that are centrifuged or otherwise handled to remove excess bath metal (see 1.2), irregular coating distribution is not normally encountered. Drainage problems not related to part design, which manifest themselves as local excess coating thickness that would interfere with function or as edge tears or spikes that present a safety hazard because of their sharpness, are grounds for rejection under the terms of 5.1. On part geometries with cavities and recesses, a buildup of zinc may result. Responsibility for remediation of these parts should be agreed to between the galvanizer and the customer.
ASTM B6-23, Standard Specification for Zinc
Regarding the purchasing of zinc slabs, Paragraph 7.1 was revised for consistency with the subsequent section 7.2 regarding the purchasing of jumbos/blocks. This does not result in any practical change to the range of slab shape/weights, but avoids the need to revise two standards (B6 and B897) should there be any weight variations in the future. See revised Paragraph 7.1:
7.1 Zinc metal may be ordered in slab, as speciﬁed in Speciﬁcation B897.
AASHTO/NSBA S8.3, Hot-Dip Galvanizing
AASHTO/NSBA S8.3, Hot-Dip Galvanizing, was approved in 2022 and published in 2023. This new guide specification was jointly developed by the American Association of State Highway and Transportation Officials (AASHTO) Committee on Bridges and Structures (COBS) and the National Steel Bridge Alliance (NSBA) Task Group 8 on Coatings. It is intended for adoption by DOTs/owners for hot-dip galvanizing bridges and other highway structures after fabrication using the batch process. AGA and several of our members were involved in the development of this standard over several years. While this specification contains some elevated requirements for bridge projects, a large portion of the specification is non-mandatory commentary regarding design and fabrication best practices to address needs specific to bridge/highway fabrications.
The AASHTO/National Steel Bridge Alliance (NSBA) Collaboration publishes all standards for free download on the NSBA website.
AGA published a more detailed overview of AASHTO/NSBA S8.3 in July 2023:
AASHTO M 111M/M 111, Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
This standard was updated to reflect the 2017 revision of ASTM A123. Additionally, M111 now contains an additional requirement to meet the standard SSPC-SP 8, Pickling. This standard is intended for acid pickling to be performed immediately prior to painting (not hot-dip galvanizing). Further, it is unnecessary for the acid pickling process at a galvanizing plant to be held to the requirements of SSPC-SP 8. See additional information from AGA explaining why the SSPC-SP 8, Pickling requirement should be waived. M111 is available for purchase from the AASHTO store.
AASHTO M 232M/M 232, Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware
This standard was re-approved without changes and reflects the 2016a revision of ASTM A153/A153M. M232 is available for purchase from the AASHTO store.
AASHTO M 180, Standard Specification for Steel Components for Highway Guardrail
This standard has a title change and was revised extensively as a result of proposed changes from NCHRP Project 22-40 and associated Report 1020: Investigation of Material Requirements for Highway Guardrail Systems. Sheet steel components galvanized after fabrication shall continue to conform to M111, but now exclude the “one-grade-less” clause of M 111M/M 111, Section 6.1. Additionally, there are a new precautions required in M180 Section 188.8.131.52 (for sheet components) and Section 9.3.2 (for posts) during shipping and storage to minimize the occurrence of wet storage stain. Field-drilled holes no longer require repair of the hot-dip galvanized coating.
New references to specifications for the hot-dip galvanizing of fasteners are included (ASTM F2329 and ASTM F436) and only a small portion of fasteners (rectangular and square washers) may be galvanized in accordance with the requirements of M 232M/M 232. Previously, all bolts, nuts and washers could be hot-dip galvanized according to M 232M/M 232.
[In-Progress] ASTM A123/A123M, Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
An in-depth review of this standard was completed between 2021-2023 and several items were developed for subcommittee balloting. Updates to Table 1 are proposed to include minimum average coating thickness requirements for castings/forgings. Additionally, a new appendix was proposed to clarify common questions regarding the interpretation of Table 1 and coating thickness requirements. Proposed notes regarding practical considerations when masking, re-galvanizing, or specifying elevated aesthetics are also included in the ballot. Pending approval at the ASTM A05.13 subcommittee level, these changes will be sent for ASTM A05 main committee ballot early 2024, with the goal of a 2024 revision date.
[In-Progress] ASTM A384/A384M, Standard Practice for Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies
A 5-year review of this standard was completed in 2023 with minor revisions for clarity and to introduce the term “progressive dipping”. In paragraph 3.1, the responsible party for reworking sheets susceptible to warpage/distortion was found to be unclear and additional verbiage is proposed to clarify responsibility. Additionally, it is proposed to reword Paragraph 4.5 to clarify what is being recommended regarding the hot-dip galvanizing of panel assemblies (sheet pre-welded to frame). The intention is to avoid progressive dipping of such assemblies. If needed, it is possible to galvanize the frame and sheet separately and then assemble the panel sometime after the sheet has been flattened out after galvanizing. Pending approval at the ASTM A05.13 subcommittee level, these changes will be sent for ASTM A05 main committee ballot early 2024, with the goal of a 2024 revision date.
© 2024 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.