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Update on NZS 3404 revision - fire section takes form

The revision of NZS 3404: 1997 progresses with updated content proposed under Section 11 - Fire section.

A steel-framed construction project

A steel-framed construction project


Building Systems Performance commissioned a robust review of NZS 3404: 1997 (Parts 1 and 2) in December 2021. This standard is considered a primary reference that is a critical part of the Building Code compliance routes as well as a key citation within the Verification Method, B1/VM1.

NZS3404 supports the design and construction of steel buildings in New Zealand. It sets out the minimum requirements for the selection of materials, corrosion protection systems, and the fabrication, erection, and construction of steel structures. It applies to building structures; crane support girders; highway, railway, and pedestrian bridges; and composite steel and concrete beams and columns.

Section 11 - fire section takes form

This is an update on the progress regarding the drafting of the fire section (Section 11). This incredibly important piece of work is being undertaken by a group of Fire specialists who are members of the Fire Working Group.

The proposed changes to this section have been made to ensure that it reflects current accepted practice. In addition;

  1. New equations are provided (but this does not reflect a significant increase in workload).
  2. The scope has been clarified stating that the fire provisions apply to non-composite steel members and systems, with no separating elements of construction. The design of individual members assumes they are isolated.
  3. The Basis of design covers the principles for standard fires and natural fires. Performance criteria are discussed with an explanation of design criteria for individual members and systems.
  4. The content regarding material properties aligns with the content in AS/NZS 2327.
  5. A temperature incremental approach is used for unprotected and protected members.
  6. Simple analyses in the domains of time, temperature and strength, including equations to estimate the time to failure for unprotected and protected steel.

Thank you for your interest in this important standard.

Kind regards,

Kevin Cowie, Chair - P3404 Steel structures Committee