Rating 4 : A relative number denoting an evaluation of rate of spread, or suppression difficulty for specific combinations of fuel, fuel moisture and wind speed
Australian Fire Authorities Council AFAC, Glossary Of Rural Fire Terminology, East Melbourne, Victoria, Australia 2011. http://www.docstoc.com/docs/31795028/AUSTRALASIAN- FIRE-AUTHORITIES-COUNCIL-GLOSSARY-OF-RURAL-FIRE, (For Fr - Brit) {7}