Group 1 vs Non-Combustible Products

Have you ever wondered what the difference is between non-combustible or Group Rated products? Or perhaps you are unsure what test certificates are required?

The 2019 NCC BCA Volume 1 Amendment 1 can also seem somewhat unclear as to when a certain products can be used and when. We understand that there is a lot to think about when specifying the correct products for your projects, so to help ease some of your confusion, or perhaps just to help reinforce what you already know, we thought we would give you a quick run down as to the difference and what options you have available to you.

What is the Difference?

The following definitions of these two words have been defined by the BCA:

Non-combustible means: 

  • Applied to a material – not deemed combustible as determined by AS 1530.1 – Combustibility Tests for Materials; and
  • Applied to construction or part of a building – constructed wholly of materials that are not deemed to be combustible.
Group 1 Rating means:

  • A Group 1 material is one that does not reach flashover when exposed to 100 kW for 600 seconds followed by exposure to 300 kW for 600 seconds as determine by AS 5637


How do I know if my product is Non-Combustible or Group Rated?

In very basic terms, to be able to determine that a product is either Group Rated or Non-Combustible, they need to undergo the correct fire testing.

Internal Wall & Ceiling Linings:

The test required for internal walls and linings is AS 5637 ( AS 5637.1:2015 – Determination of fire hazard properties, Part 1: Wall and ceiling linings) which will provide a group rating number for the product specimen.

It is also important to note that:

  • Group Numbers can only be obtained when assessed to AS5637.
  • Wall & ceiling Linings that are multi-layered & perforated must be assessed to AS5637
  • AS3837 (Cone Test) or AS9705 (Full Room Test) alone cannot be used to issue a Group Number.

Prior to the introduction of AS 5637, multi-layered panels were actually being tested as a solid panel and were therefore achieving a Group 1 Rating.  All perforated acoustic panels whether it is timber, plaster or fibre cement generally consist of multiple layers of materials glued together and they are perforated with holes or slots to achieve acoustic performance. Fire experts identified that multi-layered products with perforations can reduce the fire performance of a product, hence why AS 5637 was introduced.

External building materials

The test for external building materials is AS 1530.1  (AS 1530.1-1994 – Methods for fire tests on building materials, components and structures – Combustibility test for materials) which will confirm if it is considered non-combustible.

There is an exception to the above:

The BCA has however also recognised in Deemed-to-Satisfy Provisions C1.9 (e) that there are some materials that can be used wherever a non-combustible material is required. This means that the below materials are deemed suitable to use wherever non-combustible products are required and do not need to have undertaken 1530.1 fire testing.

C1.9 (e) states: The following materials may be used wherever a non-combustible material is required:

(i) Plasterboard.
(ii) Perforated gypsum lath with a normal paper finish.
(iii) Fibrous-plaster sheet.
(iv) Fibre-reinforced cement sheeting.
(v) Pre-finished metal sheeting having a combustible surface finish not exceeding 1 mm thickness and where the Spread-of-Flame Index of the product is not greater than 0.
(vi) Sarking-type materials that do not exceed 1 mm in thickness and have a Flammability Index not greater than 5.
(vii) Bonded laminated materials where—
(A) each lamina, including any core, is non-combustible; and
(B) each adhesive layer does not exceed 1 mm in thickness and the total thickness of the adhesive layers does not exceed 2 mm; and
(C) the Spread-of-Flame Index and the Smoke-Developed Index of the bonded laminated material as a whole do not exceed 0 and 3 respectively.

Did you know: It is acceptable to use the above deemed non-combustible products as listed above if Group 1 Rated products have been specified for your wall or ceiling linings, however this only applies if the product has not been perforated or is multi-layered. As always speak to your Fire Engineer if in doubt.

Be aware of imported products

Given that the above building materials do not require additional fire testing, it is important that you take additional care when considering cheaper, imported products that may state they are made from these materials.

It is therefore critical that you ensure that you request to see documentation that demonstrates that the products have been manufactured to comply with that the equivalent AS/NZ standard.

How do I know what Group Rating I need?

You can find out what the exact Group number for your project is by reviewing against the BCA Wall & Ceiling Lining Materials table in NCC Specification C1.10 Table 3.

However, to make it even easier, Atkar Group have introduced an online Group Rating Calculator using the data from the BCA table to help your identify your Group Rating in seconds.

What are my Product Options?

Atkar Group have numerous group rated and non-combustible solutions in our range. You can also use our wall & ceiling lining materials Group Rating Calculator to find out what Group Rating you need for your project. Click on the links below to see more:

Where to go for help?

It can be difficult to understand all the details of fire compliance, so if you have any questions or want more information on any of our fire rated products, then please contact our Architectural Team on 1300 333 833 or


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