City and fire officials announced with pride that Lawrence’s fire protection had been newly ranked among the best systems in the the state. A survey showed local improvements in fire protection would move the city’s rating from a Class 5 to a Class 2. That rating is used to determine fire insurance rates for commercial and some residential structures, meaning many local businesses and homeowners would get reductions of 4.5 to 18 percent in premium rates written or renewed after Jan. 1.