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Group Fire Rating Calculator

Your complete guide to fire compliance

Published12 Jul 2021
Written ByRebecca Fox
“It’s just one of those things that I get different information on from all sides! It can be a real headache to determine what’s to standard and what isn’t.” - Architect

We get these comments time and time again. The Australian Building Code and Fire Certification is complex and can be very confusing. However, tragedies including the Grenfell and Lacrosse Tower fires have highlighted the importance of specifying compliant materials.

With half a century of experience dedicated to developing compliant acoustic systems, Decor Systems has a range of product options to suit any building class and area without compromising on aesthetics.

In this article, learn about the Decor Systems approach to fire testing and how to ascertain what Group Rating is required for your project.

We have a huge range of Group 1-rated acoustic products.

You can download our Fire Pack for a full guide.

If in doubt, or if you have any questions, contact one of our experts.

Before we get into it, you might just want to see what products have what Group Fire Ratings. See below or download the table.

So, what's Decor System's approach to Fire Testing?

Decor Systems has fire-tested its range of acoustic products in accordance with the National Construction Code (NCC) Specification C1.10-4 to AS ISO 9705-2003 as outlined in the Building Code of Australia.

These tests govern how the surface lining materials perform in the event of a fire.

The test imitates a genuine fire situation and encompasses exposing the panels to a 100kW fire for 10 minutes; the fire’s output is then increased and the material is exposed to 300kW for a further 10 minutes.

The results are broken down into Groups 1, 2 and 3 which are determined by when the flashover point is reached. The lower the Group Number, the better the material performs in a fire. For example, Group 1 performs best when exposed to fire.

Understanding Group Fire Ratings

What is a Group 1 Fire Rating?

No flashover* point is reached during the length of the test (this is the best possible rating).

What is a Group 2 Fire Rating?

The flashover point is reached between 10 and 20 minutes. For most applications, materials classified as Group 2 and Group 3 are permitted for use as a finish, surface, lining or attachment to a wall or ceiling, in accordance with the table on the following page.

What is a Group 3 Fire Rating?

The flashover point is reached between 2 and 10 minutes. As noted above, for most applications, materials classified as Group 2 and Group 3 are permitted for use as a finish, surface, lining or attachment to a wall or ceiling, in accordance with the table on the following page.

[*A flashover is the near-simultaneous ignition of most of the directly exposed combustible material in an enclosed area]

And what about non-combustible materials then?

The Building Code of Australia (BCA) through Clause A1.1 defines non-combustibility as a material not deemed combustible as determined by AS 1530.1 - Combustibility tests for Materials.

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


(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.

DecorLux and DecorSlot perforated fibre cement sheets are manufactured from Fibre Cement, which is deemed non-combustible. However, to avoid any doubt, DecorLux has been fire-tested to AS 5637 and achieved a Group 1 rating. We're thorough like that.

Calculating the Group Rating you need

You can follow the steps below, or use the simple Group Fire Rating calculator that we've created.

How the Group Rating is calculated

  1. First, the Building Class must be identified
  2. Secondly, the Group Rating required for the Building Class must be determined as well as the location within the building.

Now you know what Group Rating is required for your specification, you probably want to know what rating our products have.

You can find Group Ratings on each of our product pages.

Most Decor Systems products are comprised of more than one variable element including a substrate and a finish option. The combination of these elements determines the fire rating. We test our products as full systems that include the substrate (e.g. MDF), the finish (e.g. SmartLook Laminate) and the acoustic backing (e.g. DecorInsul).

To make this a little easier to digest, we've created a matrix that shows the combinations that carry Group 1, 2 and 3 Fire Certifications.

Of course, the best thing to do is talk to a project consultant early on. We're experts in this field and are always ready to take your call.

Decor Systems Group Rating Matrix

Please contact us if you require additional information as to this. Certifiers have an obligation to interpret the code correctly, and we are happy to support them in this.

Speak to the experts

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