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CROSS Safety Report

Construction products- fire test certificates

Report ID: 1060 Published: 2 August 2022 Region: CROSS-AUS


Overview

A reporter has notified CROSS-AUS regarding the potentially inappropriate use of regulatory/compliance fire test methods on certain products. This has led, they say, to the circulation of inaccurate test certificates in the market and possibly the use of these products on buildings where they may not be suitable.

Key Learning Outcomes

For manufacturers and suppliers:

  • Ensure that products are certified under the appropriate test method for the end-use application
  • If uncertain about the testing procedure for a product, engage a suitably qualified independent third party to provide assurance
  • Consider withdrawing or amending product certificates that do not provide clear, transparent, or adequate justification for the method that was chosen for testing

For testing facilities:

  • To promote best practice, ensure that the appropriate test method is followed and that the test method is genuinely applicable to the considered end-use
  • Ensure that system-specific testing certificates are not used (or attempted to be used) to certify individual materials or products without adequate justification and explicit consideration of the need to extend the application of any test result
  • Promote transparency in the reporting of testing procedures and results
  • Ensure that manufacturer’s instructions are followed for the installation of testing specimens
  • Publishing a certificate produced from the use of an inappropriate testing method can have subsequent serious implications

For specifiers:

  • Fire engineers, testing operatives, product specifiers, and approvers, should be familiar with the relevant testing guidance and its underlying principles
  • Check that products, which are proposed to be specified, have appropriate test certificates and reports which are credibly applicable to the envisaged end-use condition
  • Communicate such issues with other stakeholders in the design team so that they are aware of possible pitfalls when specifying a product

For Authorities Having Jurisdiction:

  • Rigorously review any testing certificate to ensure that only products which comply with the relevant standards are used
  • Review original testing reports in their entirety, noting all relevant caveats and limits on application and extension thereof
  • Inform the regulator of deficiencies with test certificates, including how they are presented by product manufacturers

Full Report

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This report is about the issue of specifying the fire-related Group Numbers for PVC or uPVC internal wall linings, which are commonly used in commercial buildings, schools, hospitals, airports, hotels, shopping centres, aged care homes, train stations, emergency service buildings, stadiums, and other construction projects. 

Background information

The way that linings are specified through the National Construction Code (NCC) is, among other restrictions and specifications, through the assignment of a Group Number, says a reporter. This is a value from 1 to 4 – best to worst – and is derived by test. It is used as a representation of how readily a product ignites and releases heat. Depending on factors such as the building classification, location, and sprinkler protection, different Group Numbers are required to meet the Deemed-to-Satisfy provisions.

Section C (Fire Resistance) of the NCC requires that this Group Number is determined in accordance with AS 5637.1:2015 Determination of fire hazard properties—Wall and ceiling linings. This sets the decision pathway to choose between the two available test methods:

  • The first one is AS ISO 9705-2003 Fire tests—Full-scale room test for surface products. A room of standard dimensions is constructed from the lining to be tested. Following certain criteria, a Group Number can then be derived. (CROSS panel’s note: ISO 9705 is a system specific testing method, and that the results from an ISO 9705 test cannot – in general – lead to a blanket Group Number assignment which is independent of the specific jointing, mounting, and fixing methods employed in the test. This means that product-specific Group Number assignments are not strictly possible, unless the product is only used in the configuration employed when conducting the ISO 9705 test).
  • The second one is a smaller scale, oxygen calorimeter test. Both the standards AS/NZS 3837:1998 Method of test for heat and smoke release rates for materials and products using an oxygen consumption calorimeter or ISO 5660-1 Heat release rate (cone calorimeter method) and smoke production rate (dynamic method) can be used.

The employment of data from the second type of method to derive the Group Number through a prediction method is restricted to certain types of materials. These are outlined in AS 5637.1:2015 and are only homogeneous materials such as gypsum plasterboard, solid timber, wood products such as particleboard and plywood, and rigid non-thermoplastic foams such as polyurethane. Materials that melt or shrink away from a flame are not to be given a Group Number through the prediction method that employs small scale test data.

PVC and uPVC are thermoplastic materials, given how they become mouldable when heated above a specific temperature. This means that AS ISO 9705-2003 Fire tests—Full-scale room test for surface products should, says the reporter, be followed for the derivation of a Group Number.

Cause for concern

The reporter is of the mind that some of the suppliers of internal PVC wall vinyl or rigid PVC wall protection trading in Australia might be doing so without the correct Group Number certificates. It is possible, in the opinion of the reporter, that suppliers are either unaware of the guidance, or are actively seeking to obtain a test certificate through a smaller scale, thus cheaper, test method. This is exacerbated by the fact that the test houses may accept samples to be tested and then use a method that is not suitable for their type. Finally, architects, engineers, builders, installers, and certifiers also do not know what to look for in a compliant Group Number certificate, nor interrogate the completeness and validity of the information provided there.

The concern is founded on the uncertainty surrounding this situation. If these materials are tested correctly, then they can potentially have an acceptable result and the linings may be compliant with the requirements of the NCC. If these materials have not been tested with the appropriate method, or when submitted for testing the testing process did not follow the manufacturer’s installation instructions, there may be a question of compliance with the NCC.

Through their position, the reporter noted test certificates where the Group Number of PVC or uPVC internal wall linings was derived “in accordance” with AS/NZS 3837:1998. Based on the argument above, this can be misleading as it does not follow the guidance outlined in AS 5637.1:2015. These certificates are then provided to architects, builders, engineers, and building certifiers. Because these end-users look only for a test certificate that references AS 5637.1:2015 at the top, they may be accepted as valid without further questioning.

The reporter has found that how test certificates are worded can vary between test houses. It was also noted that some companies are quoting British or American Standards without any evidence of expert assessments accompanying these certificates, which should state that the foreign certificates are the same or better than the Australian Standard or test method.

The reporter is worried that if the concern they raise is correct, some buildings in Australia have been lined with a material that may not necessarily be compliant with the fire requirements set out in the NCC. If that is the case, the reporter considers it vital to see all industry stakeholders educated further on this topic, and some action put in place to catch 'bad' certificates.

Expert Panel Comments

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The reporter is to be congratulated on their stance and recognition of the issue. The panel recognises that the concern appears to be valid and genuine, both in Australia and New Zealand.

It is important to have current test certificates and test reports from the National Association of Testing Authorities (NATA/IANZ) Accredited facilities, fully and freely available for scrutiny by building professionals. These include Fire Safety Engineers, Architects and Building Surveyors/Certifiers tasked with ensuring compliance. This is critical to establishing trust and compliance in the supply chain. A testing report contains more information than a certificate, and the NCC considers a report from an Accredited Testing Laboratory as one of the requirements to provide Evidence of Suitability for a specific product.

Reliance on marketing material for safety decisions must not be the established practice going forward. It is vital to ensure that products are being specified, designed, and installed in a manner that is within the limitations of any testing reports, assessment reports, or relevant test or classification standards.

vital to ensure that products are being specified, designed, and installed in a manner that is within the limitations of any testing reports

For this reason, all suppliers must make test certificates and reports readily available and be more transparent with building professionals relying on such material for their designs. Professionals must satisfy themselves with the suitability of the chosen solution by using more robust evidence than what may be available in marketing literature.

The specific concerns raised in this report regarding incorrect test application for establishing the Group Number of wall linings have previously been raised by the Australian Building Codes Board (ABCB) and are covered in their guidance note.

AS 5637.1:2015 is very clear on the decision pathway it outlines. However, this is stated as “guidance”, and the option is available to adopt cone calorimeter results when the Group Number can be “confidently predicted” with an appropriate mathematical model. Under this standard, the reporting of the Group Number results using the cone calorimeter only requires a statement “that it was valid to test the material in the cone calorimeter for the assignment of the NCC group number”. The panel is of the opinion that a more detailed statement setting out how it was determined would be more transparent. It is also observed that the Group Number certificates provided to CROSS by the reporter do not contain this statement.

To the panel’s knowledge, the current trend is that Certifiers are increasingly aware of this problem, with some only permitting the use of test results obtained through AS ISO 9705 testing. However, more awareness is no doubt necessary and associations for accredited certifiers and building surveyors are encouraged to do more to raise this issue with their members.

Certifiers should also review the ISO 9705 testing standard to ensure that they properly understand the test standard’s view on extension of application of ISO 9705 test results on products using specific forming and mounting configurations (as is required in an ISO 9705 test) to other, different, system configurations.

Designers, specifiers, producers, and certifiers should also consider what is actually being assessed via any given regulatory/compliance fire testing method, and decide if the fundamental thermal physical underpinnings of the test method may be violated by any particular building product. Many such test methods may have originally been derived to assess specific materials or surface treatments, however, they may now be applied to products which have the potential to violate various aspects of the testing philosophy. The distinction between 'materials', 'products', and 'systems' should always be borne carefully in mind.

In conclusion, the panel considers that given the guidance from the ABCB on this matter, all building professionals should be aware of the risks entailed when accepting a Group Number obtained through the cone calorimeter results that do not satisfy the relevant sections of AS 5637.1:2015. Where this is the case, they should be requesting a clear robust explanation from the testing authority as to their justification and what empirical testing was used to form the basis of the prediction, otherwise only an AS ISO 9705 test – suitably limited in application based on the forming, mounting and fixing methods actually used in the test, as is explicitly required by the ISO 9705 testing standard – should be accepted. It is important that the process of setting up tests is open and that test results are stated as being system specific.

The CROSS panel would encourage further reporting on this subject.

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