Fire protection

DIN EN 45545-2:2013-08, which emerged from the technical specification DIN CEN/TS 45545-2:2009-07 and has been ratified since March 2013 and converted to national law, specifies the “Requirements on fire behavior of materials and components”.

To qualify plastics for certain operating and design classes of rail vehicles, the standard describes testing methods for determining hazard levels (HL) based on different requirement sets (R). In this case, HL 3 corresponds to the highest requirements.

The following tests are performed in order to qualify the plastics for electrotechnical applications:

• Oxygen index according to DIN EN ISO 4589-2
• Development of smoke gas in accordance with EN ISO 5659-2 (25 kW/m²)
• Toxicity of smoke gas NF X70-100-2 (600°C)
• Glow-wire test according to IEC 60695‑2‑11
• Vertical small flames test according to EN 60695-11-10

The un-reinforced polyamides used for Phoenix Contact terminal blocks with flammability rating UL 94 V0 meet the most stringent requirement of HL3 in accordance with the tests described in the requirement sets R22, R23, R24, R25, and R26.

In section 5.2.2.4, DIN 5510-2 “Preventive fire protection in railway vehicles – Fire behavior and fire side effects of materials and parts” requires the insulating materials that fix the energized parts in their position and are not tightly molded must meet the requirement V0 according to DIN EN 60695-11-10, which is comparable with UL 94. As an alternative, an oxygen index OI ≥30% according to DIN EN ISO 4589-2 is required for areas that are not accessible to passengers.

Both requirements are met by the un-reinforced polyamides used for Phoenix Contact terminal blocks with flammability rating UL 94 V0.

SMP 800 C describes the maximum permissible values of poisonous smoke gases when a plastic is burned. In comparison with BSS 7239 (Boeing standard), this standard specifies more precise measuring methods for the qualitative and quantitative determination of toxic smoke gases that result when a test object is completely burned. For this purpose, 6 liter of smoke gas is removed from the NBS chamber during the ASTM E 662 test between the 4th and 19th minute and fed to the analysis.

SMP 800 C limit values of toxic smoke gases in ppm:

• Carbon monoxide (CO) 3,500
• Carbon dioxide (CO2) 90,000
• Nitrogen oxides (NOX) 100
• Sulfur dioxide (SO2) 100
• Hydrochloric acid (HCl) 500
• Hydrobromic acid (HBr) 100
• Hydrofluoric acid (HF) 100
• Hydrocyanic acid (HCN) 100

The polyamides used by Phoenix Contact are many times below the critical concentrations.

Halogens are, among other things, the chemical elements fluorine, chlorine, bromine, and iodine. One
property of halogen compounds, particularly those containing bromine, relates to the reduction in the degree of inflammability when used in plastics. In the event of fire, poisonous corrosive smoke gases are formed, which can also lead to secondary damages.

For this reason, Phoenix Contact does not use any flame protection systems which contain halogens or other additives. Polyamide, polycarbonate, polycarbonate/acrylonitrile butadiene styrene (PC/ABS) and polyolefines feature halogen-free flame protection systems.

Terminal blocks from the CLIPLINE complete system are made of polyamide 6.6 (PA 6.6) with the fire protection classification UL 94 V0. According to state-of-the-art technology, these polyamides are used halogen-free, with melamine cyanurate as flame protection agent.

Phoenix Contact terminal blocks are therefore, without exception, entirely free of halogens.