Briggs, A.A., 1977. USE OF NITROGEN-FILLED HIGH EXPANSION FOAM TO PROTECT A 500-TONNE FUEL TANK. Fire Research Notes 1074
An aviation fuel storage tank was filled with nitrogen foam to observe foam behaviour and particularly oxygen contamination in aged foam. For comparison, gas inerting with a stream of nitrogen was included in the test series. In one test a hot cutting procedure was monitored for void formation and oxygen contamination of the foam. The tests showed oxygen contamination was low in foam up to 3 hours old. Voids and oxygen introduced by hot cutting were, in these tests, rapidly purged. The use of foam enabled the tank to be inerted using less nitrogen than with the gas alone, with the additional advantage of visual indication of the inerting medium.