Standards New Zealand published NZS 3404.1:2009 Steel structures Standard – Part 1: Materials, fabrication, and construction in October 2009. We talked to two users of the Standard about the changes made in NZS 3404.1:2009 and how the document is used in their business.
- David Cooke, Technical Director – Structural at Beca Carter Hollings & Ferner, is a member of the committee that developed NZS 3404.1:2009.
- Malcolm Hammond, Managing Director at MJH Engineering was previously a user of NZS 3404:1997 and is a member of the committee that developed NZS 3404.1:2009. 'It was great to participate in the committee and to discuss the practical application of the Standard,' says Malcolm. 'It gave us the ability to have some input into the clarification of the Standard.'
Benefits, improvements, and new material
As mentioned in the October 2009 Touchstone article Part 1 of the revised steel structures Standard – soon to be published, NZS 3404.1:2009 includes significant new provisions and brings all the construction and fabrication material into a stand-alone document for users. We asked David and Malcolm to talk about the benefits of NZS 3404.1:2009 for users and for the sector, and the improvements from the 1997 version of NZS 3404.
David: NZS 3404.1:2009 addresses some of the areas that have always been problematic when designing and specifying, such as corrosion protection systems, material selection for seismic ductility, and even methods of achieving holding down bolt tolerance.
This sector of the industry will be able to purchase and use just this one section of the Standard, to find the minimum requirements for materials, corrosion protection, fabrication, and erection. NZS 3404.1:2009 should become an easy reference for most small companies, as it is no longer necessary to purchase the full Standard.
The Standard now has much better correlation to construction tolerances applied across all materials (for example, concrete buildings), thus all parties should have a common understanding of tolerances and necessary allowances for erection.
The improved guidance and new material on selection of suitable steels for seismic ductility demand will give us more certainty when we design highly optimised ductile structures, and will also assist when considering alternative sourcing proposals from fabricators.
David outlined other general improvements are as follows.
- Weld testing is now consistently determined with reference to consequences of failure, and loads applied.
- Specific provisions for bridges have been added.
- Finish requirements for architectural exposed steel have been added.
- Tolerances are clarified.
- Construction provisions for composite construction are included.
Malcolm: The new materials, fabrication, and construction part is a big step forward. NZS 3404:1997 did not include basic information on protective coatings, zones, and what level of welding inspection was needed. There was a lot of confusion over those things. NZS 3404.1:2009 now includes protective coatings and zone map information. It's a far better document that we can work with every day and this is the biggest benefit for us as fabricators.
The loose-leaf format is useful and the indexing in the Standard is a lot better – it means we can get to the particular issue we need to deal with more quickly. Users will only have to purchase one document and it's a much clearer document to work with.
NZS 3404:1997 was open to interpretation, particularly on torque-wrenches and tensioning of bolts. NZS 3404.1:2009 has made the requirements clearer and easier to follow.
The identification of three recommended levels of welding quality management system for structures of varying importance and complexity is also important. While the licensed building practitioner scheme focuses on the competency of our site installation supervisors, these recommendations underline the importance of the company-wide quality management system in ensuring consistency of quality in steel construction starting in the workshop. If the company doesn't have good quality management systems in place then consistent quality won't be achieved, even with the best trades-staff.
Licensed building practitioners
It is being proposed that NZS 3404.1:2009 will be one of the indicators of competency for steel structures licensed building practitioners, for which restricted work requirements will commence in 2012.
David noted that NZS 3404.1:2009 is a good base to work from, when applied in conjunction with all the other applicable industry standards. Malcolm also noted that NZS 3404.1:2009 is a good base to work from and says, 'NZS 3404.1:2009 puts in one place all the important matters that a steel construction supervisor needs to be aware of. The way the Standard is formatted with commentary clauses alongside the rules helps to lift everyone's understanding of what is trying to be achieved.'
Seven parts for the new steel structures Standard
The revision to NZS 3404:1997 provided Standards New Zealand and the P3404 committee with the opportunity to restructure NZS 3404 into a more modern and user-friendly document. David talks about the benefits of this approach.
David: One of the criticisms of NZS 3404:1997 is that it is often necessary to jump around the document to find all the applicable requirements. With the proposal to group the Standard into seven sections by topic, the Standard should become more streamlined and easier to use as a working document.
The split will also allow specialised technical subcommittees to be formed by areas of expertise, to really advance the technical content of each section. For example, we would expect the composite design section to match worldwide best practice when completed, and similarly, the fire engineering section would set out a thorough design process which is difficult to find in any Standard, anywhere.
We asked David what sort of material he'd like included in future revisions of NZS 3404 that would help and be of use to the industry.
David: I feel is important to push through with the complete revision of the Standard. New Zealand can lead the world in seismic engineering, but our primary design Standards must be regularly updated or we risk falling behind.
For more information on the steel structures Standard and the significant new provisions in NZS 3404.1:2009, read the full story in the October 2009 Touchstone.