Nff classification – Northern Connectors Harting DIN 41 612 Connectors User Manual

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Railway specific products with NFF Classification: F1 and I2

In addition to the standard demands of connectors, as defined

in IEC 60 603-2, for example, market and application specific

demands and requirements are gaining increasing significance.

In the railway engineering area the demands made on reliability

and safety are particularly high, in order to ensure utmost

passenger safety in all instances. Especially in the case of routes

involving a high share of tunnels that only offer limited escape

route possibilities in the event of fire, the technical demands made

on the materials employed are very stringent.

In addition to the fire load, and/or the flammability of a material,

the so-called smoke gas density is a key characteristic, which is

determined based on the opacity and toxicity of the smoke gas

emissions. The risk posed by the two characteristics can not

be defined in relationship to each other, which means that both

minimal inflammability as well as minimal smoke gas density must

be fulfilled. Materials that meet both requirements are very rare

and in many instances it is only possible to fully meet one of the

two criteria.

The French NFF 16-101 railway standard defines these

requirements precisely and presents a structure of application

groups by way of a matrix.

NFF 16-101 classifies non-metallic materials used in rail vehicles

in terms of fire behavior, opacity and toxicity of smoke gas

emissions in the event that the materials should burn.

In order to enable the classification with regard to the deployment

of connectors, the following values must be applied:

1. Fire behavior class

Classification:

for I.O. ≥ 70

and no inflammation at 960 °C

for I.O. 45 - 69

and no inflammation at 960 °C

for I.O. 32 - 44

and no inflammation at 850 °C

for I.O. 28 - 31

and no afterburning at 850 °C

for I.O. ≥ 20

NC not classified

Note: The values are derived from specified test methods

determining the oxygen value (I.O.) and testing inflammability by

way of a filament.

2. Smoke development classification

Classification:

for I.F. ≤ 5

for I.F. 6 - 20

for I.F. 21 - 40

for I.F. 41 - 80

for I.F. 81 - 120

for I.F. > 120

Note: The values of the smoke index (I.F.) are derived from

specified test methods by determining opacity (specific optical

density, opacity values), toxicity (critical gas concentration of CO,

, HCl, HBr, HCN, HF, SO

in smoke).

The matrix from NFF 16-102 shows how the combination of both

characteristics results in a classification. This matrix is defined

by the contractor in each project put up for bidding. The matrix

is geared to the type of train and course of the route, whereby

special attention is given to the number of tunnels. By complying

with the high classifications I2 and F1, the designated standards

supplementing connectors according to IEC 60 603-2 can be used

in all four defined groups and for all railway applications. According

to NFF 16-102 the standard DIN connectors (I3, F4) are only

permissible for Group 1.

Diagram: Classification from NFF 16-102, April 1992

The HARTING DIN Power and DIN Signal-Portfolio looks back

on a highly successful track record in the railroad engineering

industry. Typical application areas include – among many others -

control, steering, monitoring components and modules on board

trains, as well as signal technology components or the power

supply of electronic components.

The extended range of connectors complying with the highest

classification according to NFF 16-101 and 16-102 considerably

reduce our customers’ development times: as the selected

connectors are suitable for every stipulated hazard or risk class,

they are ideal for realizing product platforms, and therefore find

use in every conceivable rail vehicle or railroad engineering

project. This dispenses with the need for complex, product specific

development work, at least in terms of selecting passive PCB

interfaces, while the technical approval process is streamlined

considerably.

In order to facilitate rapid identification the additional, railway

specific articles are designated accordingly on the product pages.