Exceptional Fire Performance with Porotherm Clay Blocks

Porotherm Clay Blocks are a naturally fire resistant cladding and structural solution for residential and commercial projects, including inter-tenancy walls.

In New Zealand interior wall materials in certain situations require a Group 1-S rating to comply with the NZ Building Code. The Group Number is a numeric representation of the performance achieved during the test and is used as a standardised benchmark for the assessment of surface finish performance. The Group Number requirements are repeated within the Acceptable Solutions C/AS1-C/AS7 relevant to each risk group.

The fire test procedure for establishing the Group Number is based on either:

  • ISO 9705, which is a full-scale room corner-test, or
  • ISO 5660, which is a bench-scale fire test on a small sample of the material.

In Australia and Europe, the same general hierarchy of risk for surface flame spread for finishes is used. While differences exist in the small-scale or intermediate-scale fire test methods adopted in the different jurisdictions, the resulting classifications are considered to be sufficiently similar to the Group Number requirements of NZBC Clause 3.4(a), such that the results can be used directly for the purpose of compliance with Clause C3.4 of the New Zealand Building Code.

In addition, materials used in exterior walls of residential buildings over 10m or commercial buildings over 7m require fire testing.

In Europe, the reaction to fire of construction products and materials are classified using the criteria and test methods described in EN 13501-1. There are five classification levels A1, A2, B, C, D, E and F (from least to most combustible). Porotherm clay construction block rates A1 and has been independently tested by Lucideon (formerly CERAM), one of the world's largest industrial testing laboratories and Exova Warrington Fire — one of Europe's foremost fire testing and certification companies. In the CERAM test, a 100mm load bearing wall remained structurally intact after a two hour fire test — making it an ideal option for boundary walls. Porotherm block walls achieve a Class A1 fire rating.

In the event of fire, Porotherm Clay Construction blocks do not burn, do not produce smoke and do not generate harmful gases. Both during and after construction, a Porotherm wall is totally fire resistant. So, in terms of Group 1-S fire rated products for both internal and external walls, Porotherm solid-plastered structural clay blocks, tick all the boxes.

These exterior wall construction and internal wall blocks are 100% organic, kiln-fired at 1200°C and rated at Group Number 1-S according to NZBC Clause C3.4(a) using ISO 9705:1993, Australian NCC Specification C1.10 Clause 4 using AS ISO 9705:2003 and the European classification using EN 13501-1:2007.

For apartments and inter-tenancy walls, Porotherm is a perfect fire resistant solution, and being part of the 'Fabric First' approach to building, the substrate itself is already safe. No added elements or products required — it's simple, easy and completely fire resistant.