Revision of NZS 4520 Fire resistant doorsets

NZS 4520 Fire-resistant doorsets serves as the benchmark for tagging, testing, and verifying fire doors used in fire separations and safe paths. The new project follows an extensive sector‑wide scoping exercise commissioned by MBIE’s Building System Performance (BSP), which identified substantial industry need for modernised, clearer, and more practical fire safety standards.

The project will be carried out by the newly established P4520 Fire‑resistant doorsets committee, which brings together fire engineers, regulators, researchers, testing laboratories, manufacturers, building officials, and industry organisations from across the country.

Why the revision is needed

Both NZS 4520:2010 Fire-resistant doorsets and NZS 4232.2:1988 Fire‑Resistant Glazing Systems are currently cited in the New Zealand Building Code as compliance pathways for passive fire protection. However, a 2025 scoping exercise found that in the 15 years since the last publication, both standards have become increasingly misaligned with current construction methods, international test protocols, and regulatory expectations.

Through two national workshops with industry stakeholders, multiple issues were identified, including:

• outdated test references, such as superseded versions of AS 1530.4 Methods for fire tests on building materials, components and structures
• gaps in guidance on smoke control doors, fire curtains, and post-installation modifications.
• lack of clarity on acceptable variations, retesting, and documentation.
• inconsistencies with glazing system marking and the absence of provisions for accessibility needs, such as wheelchair visibility through vision panels.
• references to New Zealand organisations and regulations that no longer exist
• lacks of alignment with both local and overseas manufacturing and compliance processes
• omission of considerations for newer technologies and materials and restricting innovation and creating unnecessary testing burdens for imported products.

Based on this feedback, Standards New Zealand recommended a full revision of NZS 4520 and the withdrawal of NZS 4232.2, with relevant glazing provisions covered by NZS 4232 to be updated and incorporated into the revised fire doorset standard where appropriate.

Scope of the new development project

The revision of NZS 4520 will modernise the standard, improve clarity, and strengthen compliance by addressing:

• clearer fire‑resistance testing requirements, including latching performance
• updated terminology, definitions, and reference standards
• standardised tagging, installation documentation, and photo‑based QA
• improved competency expectations for assessors and inspectors
• better access to technical assessments and test documentation
• defined pathways for smoke control doors
• guidance on modifications made after installation
• integration of updated fire‑resistant glazing requirements following the withdrawal of NZS 4232.2

The revised standard will remain focused on fire‑resistant doorsets and closely related closures, while avoiding expansion into systems governed under specialist standards (e.g., dampers or smoke curtains). The development is expected to take a little over a year to complete.

Next steps

Standards New Zealand will now begin the development phase of the project, working closely with MBIE and industry to draft the revised NZS 4520 standard over the next several months.

The revision will ultimately support a more robust, practical, and future‑focused fire safety framework for New Zealand’s built environment.