My Hebrew teacher told me שריפה is like a bad uncontrollable fire, like a wild fire. While אש is just fire in general.
I believe that, what in Germanic languages is represented by words like Brand and similar, what in Romance languages by nouns beginning with "incend", and in Slavic ones with požar/пожар group - that's srefa in Hebrew.
There is a song with words like "אש תשרוף" meaning "fire, burn!" In my understanding אש is more like camp fire, but שריפה is like flame.
Can I say: "מתי את ?התחילה את השריפה" in the meaning: When did you start the fire?