NF X 70-100: Toxicity tests for railway materials

Toxicity testing according to NF X 70-100-1 and -2 standards is performed to determine the Conventional Index of Toxicity for non-listed products (CIT_NLP) used on trains.

Testing is needed to meet requirements R22 and R23, as specified in standard EN 45545-2 on the fire behavior of materials used in railway vehicles. The method described in NF X 70-100-2 corresponds to Method 2 under the EN 17084 standard.

During the analysis, the sample is burned in a tube furnace at 600 °C, and toxic smoke emissions evolving from the sample are collected and analyzed. The concentrations of the following eight gases are measured and used to calculate the CIT_NLP parameter:

• Carbon dioxide (CO₂)

• Carbon monoxide (CO)

• Hydrogen fluoride (HF)

• Hydrogen chloride (HCl)

• Hydrogen bromide (HBr)

• Hydrogen cyanide (HCN)

• Sulfur dioxide (SO₂)

• Nitrous oxide (NO_x), including both NO₂ and NO, expressed as NO₂