Standards New Zealand has published a new technical specification (TS), SNZ TS 3404:2018 Durability requirements for steel structures and components. It covers the corrosion protection of structural steelwork exposed to New Zealand atmospheric and non-atmospheric (including in water and below ground) environments and updates and replaces the information contained in NZS 3404.1:2009 Steel structures Standard – Materials, fabrication, and construction, section 5 Corrosion Protection.
SNZ TS 3404:2018 is intended to ensure that structural steelwork is sufficiently durable meet the requirements of the NZ Building Code Clause B2; the New Zealand Transport Agency (NZTA) Bridge manual, the NZTA Protective coatings for steel bridges; as well as being compatible with NZS 3404:1997 Steel Structures Standard. Compatibility with NZS 3404:1997 is an important issue, as NZS 3404:1997 is the Standard that is cited in the Building Code AS's and VM's, while NZS 3404.1: 2009 is not cited, and also particularly as NZS 3404:1997 does not really address corrosion protection.
This new technical specification is also a simplification of the design procedure for durability determination given in Heavy Engineering and Research Association Report R4-133:2011 New Zealand Steelwork Corrosion and Coatings Guide.
SNZ TS 3404:2018 is largely based on and should be used together with AS/NZS 2312.1:2014 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings – Paint coatings, and AS/NZS 2312.2:2014 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings – Hot dip galvanizing. As the fabrication and erection provisions of NZS 3404 are in the process of being superseded by AS/NZS 5131:2016 Structural steelwork – Fabrication and erection, and AS/NZS 5100.6:2017 Bridge design – Steel and composite construction, the technical specification is also written to be compatible with those documents.
Masterspec protective coating sections generally use AS/NZS 2312.1:2014, AS/NZS 2312.2:2014 (& AS/NZS 4680) or AS/NZS 2312:2002 (for metal thermal sprays), as these cover a range of finishes useful for both structural and non-structural steel. The AS/NZS 2312 set of Standards is suitable for most ordinary types of steel work in most environments, so the Masterspec sections already very closely relates to the new SNZ TS 3404:2018, as well as being in line with AS/NZS 5131:2016 and AS/NZS 5100.6:2017.
Due the current status of NZS 3404:1997 in the NZBC and the likely move away from it to AS/NZS 5131:2016 for fabrication and erection, Masterspec will continue to use the AS/NZS 2312 set as the major reference Standards for steel corrosion protection. This will become even more relevant over time, as we develop a new structural steel section based on AS/NZS 5131:2016.
Masterspec sections that are the most relevant for steel corrosion protection:
- 6745 PROTECTIVE COATINGS - STEELWORK & related branded sections (all available in Standard, Structural & Civil, Services, Landscapes and Interiors)
- 6781 HOT DIP GALVANIZING (available in Standard, Structural & Civil, Services, Landscapes and Interiors)
- 6782 METAL SPRAY CORROSION PROTECTION (available in Standard, Structural & Civil, Services, Landscapes and Interiors)