Stephen Harris Staff Engineer at UL UK, introduces the standard testing requirements for reaction to fire of building products, looks at what can influence fire test performance and examines the added value that independent third-party certification offers those who specify products for the built environment.
Stephen Harris, Staff Engineer, UL
Fire in buildings puts the safety of occupants at risk, either directly, by exposure to the fire conditions, or indirectly, as a result of the response of the building to exposure to fire. Potential responses of the building that could represent a risk to life safety include:
Reaction-to-fire testing measures the contribution of a material or system to fire, at the early stages of a fire (the first five points detailed above), as this is crucial to the safe evacuation of a building. European tests differ in methodology from the older British standard tests. There are some equipment differences, and in particular the test result classification, are different. The European tests classifying the smoke release performance of a product and also the number of particles/flaming droplets the product produces. Both of these are key elements in the risks that a product poses when involved in the early stages of a fire.
Regardless of the test method, all test results specifically relate to the performance of the specimen of the product under the particular conditions of test, i.e. test results provide a guide to the potential fire performance of a product and may not reflect the exact performance of the product under real fire conditions. However, it is a benchmark and offers a standard by which to compare products and their likely performance in a building.
The United Kingdom Accreditation Service (UKAS) accredits laboratories to test, measure, and evaluate the physical properties of materials, and components. Laboratory accreditation is carried out against the internationally recognised standard ISO/IEC 17025 to assess factors relevant to a laboratory’s ability to produce precise, accurate tests and data. These factors include:
European testing is conducted on construction products and building elements including rubber, plastics, paper, and wood, using standardised test equipment methods.
BS EN 13501-1 provides the reaction to fire classification procedure for all construction products, including products incorporated within building elements. Products are considered in relation to their end use application. BS EN 13501-1 separates these types of products into three categories, which are:
Classification is achieved via one or a combination of tests.
BS EN 13501-1 is the fire classification specified in each of the product standards that enable products to be categorised, as required by The Construction Products Regulation.
The classification is split into three parts, the main classification, the smoke classification and the flaming droplet classification.
Many construction products that have achieved a test classification can be CE marked (or UKCA marked from 2023). The CE mark by itself does not necessarily indicate that the product is suitable for the end application. It will indicate a set of performances against specific criteria through the manufacturers Declaration of Performance, which will accompany the product when sold. One of those declarations will be the fire performance classification. However, it is essential to check that the product’s performance is suitable for the end use application.
There is no direct comparison between British Standards tests and European Standards tests results. Therefore, a product that passes a British test and has been classified under the national system cannot be regarded as equivalent to a particular European test result. However, it is generally accepted that a European test classification can be regarded as the equivalent to the British test result. This assurance of equivalence is a result of historic research testing completed at accredited UK test laboratories. Because of the complexities of the European test, the way in which results are calculated, plus the additional smoke and flaming droplet suffixes for the European tests; the BS results cannot be compared in the same reciprocal way.
Until the revision in 2019, UK Building Regulations listed both British and European types of tests as suitable evidence of performance and it specifies the required classification of materials for specific areas within the building. However, EN performance is now the required reaction to fire performance classification. Some products may still be legitimately in the marketplace with only a British classification. However, Approved Document B should be consulted prior to specification use and acceptance from building control.
Many different products and system properties can influence the fire performance of a product and any variation from that which was tested to that which is installed onsite can mean the products performance could be significantly worse than the indicated test classification.
These include:
Independent Third-Party Certification offers very good assurance that a product is manufactured and sold as the same product which was tested.
In the UK, the Department for Business, Energy and Industrial Strategy (BEIS) supports the use of conformity assessment through accredited certification bodies.
“Conformity assessment and accreditation are important parts of the nation’s quality infrastructure”
“Conformity assessment is the demonstration that what is being supplied actually meets the requirements specified or claimed”
“Conformity assessment is thus an indispensable part of the nation’s business, technology and quality infrastructure”
Third-party certification means that a UKAS accredited independent organisation has, for example, reviewed the manufacturing process of a product and has independently determined that the final product complies with specific standards for safety, quality, or performance. This review typically includes comprehensive formulation/material reviews, testing and facility inspections. Most certified products bear the certifier’s mark on their packaging to help consumers and other buyers make educated purchasing decisions.
Product certification schemes will also typically have continued annual audit of the factory of production to ensure the product remains the same as that which was tested and can include sample testing requirements to ensure the reaction to fire performance of the product remains the same.
Fire test reports are normally difficult to obtain from manufacturers for their products and they are not normally supplied with manufacturers own product specification details. The fire performance is normally declared in the supporting literature. With a certificated product however, the information about the product is publicly available from the certification bodies website, which details the test configuration, including substates and adhesive type/application rates, test results/classification and any range of variations covered. So, if a wall covering achieves an EN Classification of B s1 d0, for all colours and in three different weights. The consumer can be assured that if the product as supplied fits those parameters when purchased, its fire performance is covered by the certification.
As another example, of why third-party certification offers assurance above those of a single test report, the amount of resin is a key factor in the fire performance of mineral wool insulation products. Too much resin will add to the amount of organic combustible material within the product, which will add to the products combustibility. During the factory audit, the auditor from the certification body will examine the results of the internal tests carried out at the factory. They will be able to check what happened to non-conforming products i.e., those with too much resin added. In addition, they will check the type of resin and the tests done to ensure the resin is consistent with that which was included in the tested samples. Samples of the product will also be purchased from the supply chain and retested independently, to see if the same results are achieved.
About the author
Stephen has over 24 years’ experience in fire testing and certification. He has a fire engineering degree from UCLAN and understands why reaction to fire is so important in the built environment. Working out of UL’s U.K. office, he manages European testing carried out at UL’s ‘Centre of Excellence for Fire-Testing Laboratory in Rosenheim, Germany.
Get in touch with UL for further information, here.
