Should a smoke alarm be installed in the attic?
FEMA writes:


  Few, if any, smoke alarms are Underwriters Laboratories 
  (UL)-listed for use in the temperature extremes an attic can 
  experience. Few, if any, codes require alarms in one- and 
  two- family residential attics where nearly all (90 percent) 
  of attic fires occur.
  
  — “Attic Fires in Residential Buildings”, Topical Fire Report Series 11(6), January 2011