When is it acceptable, if a small fire is set in a West Philadelphia High School locker or hallway, not to evacuate students and staff? Never, says high school Home and School Association president Marsha Brown. She has told the Philadelphia School Reform Commission that a change in procedure this spring has "greatly compromised" student safety. District chief safety executive James Golden says if a fire is small and presents no danger of spreading, the school might not be evacuated, That way, students can continue their studies rather than face constant disruption. West Philadelphia High has had 23 fires this year.