Onyomi Examples
熾烈 （シレツ） fierce (fight, competition, etc.), severe, hot, hard, bitter, keen, cutthroat
熾盛 （シジョウ） vigor (like leaping flames), liveliness
Kunyomi Examples
熾る （おこる） to catch fire (of charcoal), to start burning, to burn away, to burn merrily
熾す （おこす） to build (a fire), to make, to start, to light