N.J. Stat. § 40A:14-55
"Fire department and force", "fire department or force" or "fire department" means the officers and members organized to fight fires in the municipality;
"Fire duty" means active participation in the usual duties of a fireman under the direction and supervision of the official in charge of the fire department and force;
"60% of duty" means actual recorded attendance and rendering of fire service at not less than 60% of regular alarms of fire answerable by the members during any calendar year; the total number of alarms used in computing said percentage may include not more than 20 fire drills called at the direction of the official in charge of the fire department and force;
"50% of duty" means actual recorded attendance and rendering of fire service at not less than 50% of regular alarms of fire answerable by the members during any calendar year; the total number of alarms used in computing said percentage may include not more than 20 fire drills called at the direction of the official in charge of the fire department and force.
N.J.S. § 40A:14-55