European cladding standard eliminates “misleading” fire tests

Building cladding such as plasterboards, wooden panels and other boards mounted on walls and ceilings plays an important role in fire safety, of course, as it must protect underlying materials in the event of a blaze. The new standard will provide a more uniform safety level across countries, it’s stated, as well as new and flexible opportunities for manufacturers.

As it stands, when tests are performed to see how a cladding solution reacts under fire exposure, the assessment is made on a visual basis. This can produce different results depending on which laboratory conducts the testing process.

“It can be a bit subjective and cause variations, while disagreements often arise in borderline cases,” stated Jeanne B Kirk, resistance to fire engineer at DBI.

The new standard aims to address this challenge by introducing a temperature-based method in which pass/fail is determined from measured temperatures (eg whether they rise more than 270°C). The DBI has been involved in developing the specifications for where and how temperature sensors should be placed in the set-up in order to provide an accurate picture of whether the underlying material risks becoming charred.

“It’s about collating data sets that show how the material actually performs,” continued Kirk. “If the temperature exceeds the limit, the cladding system automatically fails. This makes the conclusion much more objective.”

Classification system

In the European classification system, K1 10 and K2 30 are used to indicate that a cladding solution must protect the underlying material from fire exposure for ten or 30 minutes respectively. These classes have different requirements and application areas, including where and how the material may be installed.

The new standard adjusts and expands on the requirements for how these classes are documented in order to avoid a product being approved for an application for which it’s not truly suited.

The way in which application areas are defined will also change. Until now, it has been possible to test on one standard material (particleboard) and then obtain documentation for multiple application areas. In some cases, however, this has led to solutions that were less safe than the test indicated.

The new approach introduces three types of standard test substrates: EPS (expanded polystyrene), low-density materials such as insulation and the classic particleboard. The chosen substrate will determine the subsequent application area.

“If you test on EPS, which is considered the worst-case scenario,” added Kirk, “you’re allowed to install your cladding on anything. If you test on insulation, you can only install it on similar low-density materials. In both cases, the installation method must be the same as in the test.”

This makes test results more reliable and affords manufacturers clearer choices. For example, a plasterboard producer who previously had to conduct a separate test for each desired substrate type – such as cellulose, seagrass, PIR and PUR – will now be able to conduct a single test on EPS to cover them all.

Wall-mounted testing

The revised standard also brings several other benefits. Among them is the possibility to test cladding as wall-mounted solution rather than a ceiling-mounted one if it will only be used vertically.

“Many people ask why they cannot just test cladding as a wall,” noted Kirk, “given that this is how it’s actually installed in practice. This will now be possible, but then, of course, it can only be used as wall cladding.”

It will soon be possible to vary fastening methods. For example, if you test with nails, you will in the future be allowed to use screws in practice (something that was previously not possible without a separate test or an assessment in the European classification system).

Plan for the new standard

The revision also makes it easier to incorporate bio-based materials into construction. Until now, it was necessary to test each individual product and manufacturer if the desire was to use bio-based insulation. Now, it will be allowable to switch between suppliers as long as the materials are of the same type and have equivalent properties.

“As it stands, you cannot change anything,” affirmed Kirk. “Not thickness, nor the density and not the manufacturer. “Now we’ll have a standard method that allows switching within the same type.”

The revision has been seven years in the making The DBI recommends that manufacturers begin to plan test procedures according to the new method.