Ignitability of anechoic chamber foam by electric currents

Anechoic chamber foams are easily ignited by passage of current through them. Two distinct ignition processes can be observed. The first is a contact fire that results when two sharp points which are at a potential difference of more than 100 V touch the conducting foam. The second is an I²R heating of the interior of the foam which begins with smoldering, then a glowing chunk of foam inside the material which grows and usually ignites. An unexpected by-product of burning carbon-impregnated foam is the voluminous release of dense toxic smoke (Tatem and Williams [1]).