Is it safe to rely on transactions in Firebird 2.5 Embedded DB in case of power outage?

How it's safe to say that the following list of action will never be reflected in DB in case of power outage somewhere in the middle of #2 line, before transaction is committed?

#1 begin transaction
#2 delete record in table A that cascade deletes another record in table B
#3 update another record in table C
#4 commit transaction