The actual classification used by French regulations for the classification of fire behaviour of materials/ component is described in: - NF F 16-101: "Rolling stock - Fire behaviour - Materials selection"
- NF F 16-102: "Rolling stock - Fire behaviour - Materials selection - Application for electrical equipment".
This classification regards substantially three vehicles categories: A1, A2 and B.
Theses standards provide the classification of the material by "reaction to fire" and "smoke" (combination of smoke opacity and toxicity). The product of the above parameters gives the "risk index".
Reaction to fire test
For wide specimens, the "reaction to fire" tests classify the material/product into one of six categories: from M0 to M5 and are obtained from combination of the parameters measured. Theses reaction to fire tests comes form the buildings standards.
The principal test used in this standard is the "Epiradiateur". According to NF P 92501 both for rigid and flexible materials more than 5 mm thickness are evaluated. NF P 92503 is used for flexible materials with thickness up to 5 mm. If dripping is noted in the above tests, NF P 92504 and NF P 92505 test s (rate of flame speed) are used.
A complementary test for floor covering is the radiant panel test NF P 92506 which is used only if in the primary test (NF P 92501 and NFP 92503) the material does not obtain the M1 or M2 classification. The NF P 92510 test (calorific potential l) is used to give materials classified in M1 class (below NF P 92501) the M0 class (if the heat of combustion is less than 2500 kJ/kg).
For small specimens, two tests are used: Oxygen index (NF EN ISO 4589-2 ) and glow wire test (NF EN 60695-2-10). These tests classify the materials into five classes: from I0 to NC (I5). The same tests are used for the electrical materials as described in NF F 16 102.
Table 1: small specimens reaction classes | Class | Result of test | | OI | Glow wire | | I0 | >= 70 | No ignition at 960° C | | I1 | >= 45 | No ignition at 960° C | | I2 | >= 32 | No ignition at 850° C | | I3 | >= 28 | Ignition does not persist at 850° C after glow wire is withdrawn | | I4 | >= 20 | | | NC | < 20 | Non classified |
For wires
The wires are assessed according to the NF C 32-070 standard testy method based on the horizontal flame spread along a wire.
Smoke parameters
Concerning "smoke" parameter, as described in the standard, this is obtained from the combination of "smoke emission" and "toxicity index".
The first one is evaluated by the NF X 10-702 (Smoke Density Chamber ) and the second one with NF X 70-100 . The Assessment of smoke toxicity is focused on CO, CO2, HCl, HBr, HF, HCN, and SO2. The NOX, acrolein and formaldehyde derivatives will be probably integrated in the requirements in a near future. The toxic analysis can be realised with the ionic chromatography.
According to NF 16101, the combination of these two parameters gives the "smoke value" with classes from F0 to F5.
The Smoke Density Chamber (ASTM E 662 in USA ) is used widely in testing of transportation.
This apparatus measures smoke generation from small, solid specimens exposed to a radiant flux level of 25 kW/m2 in a flaming (piloted ignition) or non-flaming mode. The smoke produced by the burning specimen in the chamber is measured by a light source - photometer combination. The attenuation of the light beam by the smoke is a measure of the optical density or quantity of smoke that a material will generate under the given conditions of the test.
The French standard gives a complete set of allowable pass criteria by using 18 matrices. Each grid is available for a specific material/component with three classes: Acceptable, Acceptable with agreement of user, and Not acceptable.
Table 2: M and F requirements versus category | | A1 | A2 | A3 | | Ceiling | M0F0 | M0F0 | M1F1 | | Wall | M1F1 | M1F1 | M2F1 | | Curtain | M1F1 | M1F1 | M1F1 | | Light | M1F1 | M1F1 | M1F2 | | Seat (each component) | M1F1 | M1F1 | M1F2 | | Flooring | M1F1 | M2F1 | M2F1 | | Interior Wires | AF1 | AF1 | BF2 | | Exterior Wires | BF1 | BF2 | CF3 | | Exterior material | M2F1 | M2F2 | M3F3 | | Bed furniture | M1F1 | M1F1 | M1F1 |
Table 3: light diffusers requirement for A1 category, matrice n°4 | | I0 / M0 | I1 / M1 | I2 / M2 | I3 / M3 | I4 / M4 | NC | | F0 | A | A | AA | AA | NA | NA | | F0 | A | A | AA | AA | NA | NA | | F0 | A | A | AA | AA | NA | NA | | F0 | A | A | AA | NA | NA | NA | | F0 | A | A | NA | NA | NA | NA | | F0 | A | NA | NA | NA | NA | NA |
A: acceptable, NA: non acceptable, AA : Acceptable with agreement of user |
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