EN 17084 Railway Applications - Fire Protection in Railway Vehicles - Toxicity Testing of Materials and Components

The European standard “ EN 17084 Railway applications - Fire protection in railway vehicles - Toxicity testing of materials and components” describes the measurement of the toxicity potential of combustion products based on two test methods. These methods are:

• Method 1: Smoke chamber field-based testing method with Fourier transform infrared spectroscopy (FTIR) gas analysis techniques described in the standard “Plastics - Smoke formation - Part 2: Determination of optical density by a single-chamber test”.
• Method 2: Tube furnace small mass based test method described in the standard “NF X70-100-2 Fire tests - Analysis of gaseous wastes - Part 2: Tube furnace thermal decomposition method”.

The EN 17084 standard also specifies test equipment and establishes calculation procedures for evaluating toxicity data. This standard can be used, among other things, to determine toxic gases originating from devices installed in tunnels.

For the purposes of this standard, the following definitions apply in addition to the terms and definitions given in EN ISO 13943, ISO 8421-1 and EN 45545-1:

• CIT(n), conventional index of toxicity (dimensionless value), where n is the time in minutes since the start of the test.
• FEC, fractional effective concentration. For full details see EN ISO 13943
• FED, fractional effective dose. For full details, see EN ISO 13943.

When conducting a product toxicity assessment, in principle, test samples for a product used in a railway vehicle are heated under controlled conditions to induce combustion. The gases are analyzed to determine the potential toxicity of the combustion products. The product should be tested in relation to the exposed surface under actual use conditions. Where both surfaces are exposed and the product is not symmetrical, each surface should be tested.

Samples should be representative of the product to be tested. The same material should be cut, sawn, shaped, or printed from the sample area and should be as close to the same thickness and density as in the end use as possible. Covering materials should be prepared to be as similar as possible to the end use conditions. The test sample may include adhesives, varnishes, substrates, and supports. Details of test sample preparation should be reported.

The conditions selected are representative of fires that could affect railway products during the development phases or development stages of a fire inside or outside a railway vehicle. Two methods are detailed in this standard for determining the composition of gases produced by the combustion of specified railway products:

• Method 1: EN ISO 5659-2 Fume chamber field-based testing with Fourier transform infrared spectroscopy (FTIR) gas analysis techniques
• Method 2: Tube furnace NF X70-100-2 Small mass based testing.

A standard such as EN 45545-2, which specifies the product's reaction-to-fire performance requirements, should specify the test method, test specifications, and test rules to be used and the required results. CIT values ​​should be calculated in accordance with this standard. In the case of Method 1, FED and FEC values ​​should also be calculated.

• Method 1 Smoke chamber: This method is based on exposing a test sample to radiant heat with or without the application of a pilot flame. The test apparatus used is described in EN ISO 5659-2, with additional information provided in this standard. This method yields toxicity data that are processed in accordance with this standard for product evaluation and final classification purposes (which are beyond the scope of this standard). Smoke density measurements can be performed simultaneously as described in EN ISO 5659-2.
• Method 2 Tube furnace: This method is based on the exposure of small test samples (1 g mass) to heat in a tube furnace. The test apparatus and procedures used are described in NF X70-100-2 and ISO 19701, with supplementary information provided in this standard. This method yields toxicity data that are processed in accordance with this standard for product evaluation and final classification purposes (which are beyond the scope of this document).

For the scope of this standard, the following 8 gas components are analyzed: carbon dioxide, carbon monoxide, hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen cyanide, sulfur dioxide, and nitrogen oxides.

EN 17084 is an important fire safety standard for railway vehicles, specifically addressing the toxicity of gases released when materials and components burn. This standard was deemed necessary for the following reasons:

• Passenger and crew safety: In the event of a fire, the toxic gases released can be more dangerous than the flames themselves. This standard helps reduce fatalities and injuries by ensuring that materials emit low toxic gases under fire conditions.
• Standardized toxicity testing: This standard provides a uniform test method for evaluating and measuring the toxicity of combustion gases. Materials are tested for carbon monoxide, hydrogen cyanide, hydrogen chloride, and many similar toxic gases.
• Compliance with railway fire safety regulations: This standard supports compliance with EN 45545-2, the broader European standard for fire protection in railway vehicles. Toxicity is one of the key parameters affecting material classification, along with flammability and smoke density.
• Risk reduction for evacuation scenarios: This standard reduces the risk of respiratory injuries during evacuations in tunnels or enclosed environments where toxic fumes can accumulate. It helps extend the escape time available for passengers and personnel.
• Material selection and system design: Finally, this standard guides train manufacturers, suppliers, and designers in selecting safer materials for interior components, wiring, seats, insulation, and similar materials. It supports sustainable and safety-oriented design in railcars.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the EN 17084 Railway Applications - Fire Protection in Railway Vehicles - Toxicity Testing of Materials and Components standard.