Abstract
This paper reviews electrical ignition phenomena from a
wide perspective through statistical, modelling and
experimental tools. A rather comprehensive concept of
electrical ignition phenomena has been described. Several
databases indicate that defective cables leading to short
circuit and ground shorts, as well as loose connections
leading to overheating, are the most common reasons for
electrical ignitions. For modelling an overheated cable a
mathematical model has been proposed, which compares
favourably with a limited set of experimental data.
Experiments on PVC cables showed self-heating a possible
but improbable cause of initial ignition. The literature
review of physical models of electrical arcs established
conditions where ignition of cables might be possible. A
limited set of tests under poorly controlled conditions
succeeded, not producing long lasting arcs amenable to
sustained ignition. The reason for experimental failure
is believed to be too violent release of energy, which
blew off the flames.
Existing semiquantitative models of flame spread are
shown to be able to describe salient features of cable
ignitions despite clear deviations of the initial
assumptions of the model. Laboratory tests of electronic
components heavily or destructively overloaded did not
generally lead to ignition of adjacent material because
of sudden release and subsequent destruction of the
component. Only power transistors heavily mounted on
printed cards seemed able to start ignition of the card.
The phenomenon can be modelled as a piloted ignition
similar to flame spread on cables.
Original language | English |
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Place of Publication | Espoo |
Publisher | VTT Technical Research Centre of Finland |
Number of pages | 112 |
ISBN (Electronic) | 951-38-5386-1 |
ISBN (Print) | 951-38-5385-3 |
Publication status | Published - 1999 |
MoE publication type | D4 Published development or research report or study |
Publication series
Series | VTT Publications |
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Number | 387 |
ISSN | 1235-0621 |
Keywords
- ignition
- fire safety
- fire propagation
- fire protection
- cables
- electric devices
- electrical components
- conduction
- heat transmission
- self ignition
- short and ground circuits
- arcs