Fire safety is a priority for the plastics industry producing construction products. The reason is simple: plastic products are, like all organic products, combustible. However, plastics can contribute in an undisputable way to energy-efficiency and sustainability of the constructions and improve quality of life. As plastics continue to push the barriers of modern architecture and contribute to greater energy efficiency and cost savings, they have also, in many cases, benefitted from improved fire performance.

The use of plastics is essential for the construction of buildings, and the buildings in which they are used must meet national requirements for fire safety. That is why manufacturers must subject their materials, products, and systems to the appropriate fire performance tests. Manufacturers have the responsibility to provide the required information to enable specifiers to make the right product/system selections for the applications under consideration. Comprehensive documentation, correct installation and appropriate use and maintenance, are also important.

A broad range of plastic materials are used in construction (e.g. high-performing pipes, efficient and light thermal insulation and long-lasting waterproofing membranes) to ensure the durability and comfort of homes and workplaces.

Over the years, building and construction techniques and plastic products have been developed to attain improved fire performance. These improvements have been achieved by various means, including for example, investments in product design to influence behaviour under fire, alterations in product compositions to reduce ignitability and/or smoke generation and better installation techniques or building design to prevent fire spread. Some plastic devices or articles, thanks to their lightness and their resistance to severe fire conditions, have become everyday partners for fire-fighters:

• items of safety equipment, such as helmets or suits;
• plastic pipes used in sprinklers;
• plastic coated fire hoses; and
• products like bespoke plastic roof lights designed to melt in case of a fire and to allow for smoke ventilation, thereby improving fire safety for fire-fighters and occupants.

Plastic products can be tailored to meet specific needs. Formulations can be adapted, so that specific fire performance requirements can be met. The performance of all plastic products can be improved by one or more of these options:

• covering them with protective layers e.g., thermal insulation protected by gypsum plasterboard, mortar, or reinforcement layers; and
• changing the formulation to improve the fire performance of the polymer itself.

Foam insulation and fire safety

Different foam insulation products exhibit differing thermal, mechanical, acoustic, and fire performance properties. In the current context of the Renovation Wave, improving the energy efficiency and the thermal performance of buildings are key actions to ensure the success of the Green Deal. When used correctly in their intended application, plastic foam insulation materials (e.g. expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethanes (PUR/PIR) and phenolics (PF)) can be installed in buildings without compromising the safety of the users/occupants of that building. These products are installed in walls, roofs or floors in which they are usually protected by layers of other materials such as concrete, plasterboard or render.

Assessing fire performance

A construction system is an assembly of different components. The configuration of system components for a specific project depends on performance requirements of that project. Construction systems can be complex and may include elements such as fire barriers (required to stop the spread of fire) or thermal barrier layers.

It is paramount to state that the fire performance of a building is not determined by the properties of the individual components (products) of which it is made, but by the performance of complete construction system (e.g. complete roofs or facades). This performance is determined by the interaction between all the products that make up the complete construction system: including their fixings and the way they are assembled. Please refer to: https://www.modernbuildingalliance.eu/EU-fire-safety-guide.

Methods of assessment

1/ Reaction to fire - product

The reaction to fire of construction products is determined in standardised tests, and categorised using three parameters: their combustibility, ignitability & contribution to fire growth and smoke development.

These tests can be:

• at bench-scale, focussing on material or product properties (e.g., EN ISO 1182 for non-combustibility or EN ISO 1716 for heat of combustion); or
• at small-scale focussing on product flammability properties, (e.g., EN 13823 Single Burning Item (SBI)).

Fig.1 Bench-scale material test (EN ISO 1716)

Bench-scale reaction to fire tests on materials and products

Bench-scale test methods can be used to assess the reaction to fire of samples of materials and products. A bench-scale test can be based on only a few grams of material or product transformed into powder. The gross calorific potential test (EN ISO 1716) for example, determines the energy released by a few grams of material when ignited and burnt in oxygen. It is one of the tests which serve as the basis for the Euroclass system (class A1, A2, B, C, D, E or F) that classifies the reaction to fire of construction products.

Small-scale reaction to fire tests on products

Intermediate-scale tests, e.g. EN 13823 (SBI), are also  used to assess the reaction to fire of products. Results of small and intermediate-scale tests provide information that allows the classification of products in relation to a specific fire scenario. They are used to test and classify products in a standardized way but do not necessarily replicate the way they will perform at real scale in their intended application.

The SBI test, for example, represents a scaled down room corner test, simulating a waste-paper bin fire in the corner of a small room, and measuring the response of the products on the surface of the walls and ceiling of that room to the fire.  The test, however, is also used for all other construction products (except flooring), including those that are applied in other scenarios.

Material and product tests do not generally consider the additional materials in a structure, and do not assess how all components perform together as a system during a fire.   For that, the most reliable approach is to test the complete system.

 

2/ Reaction to fire - systems

Small- and intermediate-scale reaction to fire tests on systems

Small-scale tests, e.g. EN 13823 (SBI), can also be used to assess the reaction to fire  of assemblies of products, as can intermediate-scale tests, e.g. ISO 13785-1 for facades or CEN TS 1187 for roofs.   They test systems in a standardized way but do not necessarily replicate the way they will perform at real scale and/or their intended application.  They can, to some degree, take account of the additional materials in a structure, and can assess how all components perform together as a system during a fire.    However, the extent to which they can do this is limited by their scale.   Aforementioned, the most reliable approach is to test the complete system in a large scale test.

Large-scale reaction to fire tests on systems

Large-scale reaction to fire tests of systems, enable the assessment of the interaction of all components and materials of complete systems (walls, façades, roofs…) in a more realistic situation. They enable consideration of interactions between the different layers and components, e.g. for a façade, the insulation, finishings, fixings, cavities, fire barriers, etc. For some assemblies, they are the only way to validate the performance at real scale in the intended application since they allow the observation of the interaction of the different components in a fire scenario that is representative of real fires.

For façades, different large-scale tests coexist in Europe, for example: the British BS 8414; the French LEPIR II; the German DIN 4102-20 and DIN 4102-24 and the SP Fire 105 in Sweden/Finland etc. The European Commission is currently developing a harmonised approach to assess the fire performance of façades, using BS 8414 and DIN 4102-20 as a basis. The real performance of the different components together can only be assessed with such large-scale tests. There is, for example, no individual test method on cavity barriers and they must therefore be tested with a large-scale façade test as part of the whole system. The BS 8414 test is considered one of the most stringent façade fire tests worldwide.

Fig. 2 – Example of large-scale façade test (BS 8414- 1:2020)

 

Learn more about fire safety of façades.

Construction systems including combustible components can meet the requirements of these large-scale tests, when installed in appropriate configurations.  Focussing on material and product classifications based on bench- and small-scale tests may be misleading.

 

3/ Fire Resistance – products & systems

Floors, walls, doors, and ceilings of building compartments (rooms) in many cases need to resist fire long enough to limit the spread of fire and smoke – this is known as compartmentation. This will allow for safe evacuation, and for fire fighters to control and extinguish a fire before it has spread to a complete building.

Constructions containing high performance materials, classified as combustible, may provide high levels of resistance to heat, penetration of hot gases, flames and/or stability when designed properly and tested and classified accordingly.

Fire safety Regulations

Fire safety of buildings is a national competence because it is directly influenced by national construction traditions/techniques and other factors, like, for example, the time needed for fire brigades to reach a fire.

The EU supports Member States via harmonised standards for testing, classifying and declaring the performance of products used in buildings. The European regulatory framework also requires producers to present clear information about their products’ performance when selling them on the European single market. This allows building designers and specifiers to select the right products to meet national performance requirements for specific applications.

The Modern Building Alliance has developed a comprehensive and structured framework for use by Member States in considering their regulatory approaches to building fire safety. Closely linked to the 7 layers of fire safety in buildings, this holistic approach enables consideration of, not only the building design and construction, but also technical installations and fire safety management throughout the lifetime of the building, including clarification of roles and responsibilities in the value chain. The ultimate goal of such a framework is to provide a clear basis to assist Member state regulators and the construction sector, in the identification of gaps in fire regulation, and best practices for fire safety. The Modern Building Alliance believes that getting competent Fire Safety Engineering professionals involved at all stages of the design and construction of complex buildings can ensure that fire safety has been fully considered.

Learn more about fire safety competency

Industry-wide efforts to further improve fire safety

The construction industry makes significant efforts to protect society from the dramatic consequences of fire. As a result, between 1 and 8% of total construction costs are spent on fire safety measures. These costs are directly dependent on the type of building and can increase considerably for sensitive buildings like schools and theatres. In the case of shopping centres, fire safety measures can amount to 10% of total construction costs^[1].

For the plastics industry, the fire performance - in its broadest sense - of products used in long life applications comes before any other consideration.  Plastics manufacturers have a duty to design their products and develop guidelines on how and where to use these products in compliance with fire regulations and standards.

Each type of building has its own specific potential fire risks. Therefore plastics, like all other construction materials, must be used in the correct applications and under appropriate conditions to ensure the safety of the users/occupants of that building.

[1] World Fire Statistics Bulletin no. 29, April 2014 – The Geneva Association