rtk label printer

NFPA 704 Diamond Information: Yellow Segment

Yellow region - Reactivity

The yellow region of the RTK diamon indicates reactivity and may contain either a 0, 1, 2, 3 or 4. These numbers indicate the level of explosion, detonation or reaction risk, and can be interpreted as follows:
  •  4  Readily capable of detonation or explosive decomposition at normal temperatures and pressures (e.g., nitroglycerin).
  •  3  Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked (e.g., fluorine).
  •  2  Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water (e.g., phosphorus).
  •  1  Normally stable, but can become unstable at elevated temperatures and pressures (e.g., calcium).
  •  0  Normally stable, even under fire exposure conditions, and is not reactive with water (e.g., helium).


  • More information on the RED NFPA DIAMOND segment
  • More information on the NFPA DIAMOND BLUE segment
  • More information on the NFPA DIAMOND WHITE segment
  •