How to Read the NFPA Diamond Red Section: Flammability. The red-colored section of the NFPA Diamond is located at the top or twelve o’clock position of the symbol and denotes a material’s flammability and susceptibility to catching fire when exposed to heat. Yellow Section: Instability. Blue Section: Health Hazards. White Section: Special Precautions. Click to see full answer. In respect to this, what do the numbers mean on the HMIS and NFPA Labels?Two important chemical hazard labeling systems used in healthcare facilities are the Hazardous Materials Identification System (HMIS®) and the National Fire Protection Association (NFPA) NFPA 704 system. This labeling system was developed by National Fire Protection Association.Subsequently, question is, what do the numbers mean on hazard signs? The numbers superimposed over the colors rank the severity or danger, ranging from one to four, with four being the highest rating. The blue indicates potential health effects. A four in the blue means severe and immediate health effects, including death, and a one time exposure can cause lasting health problems. Hereof, what is the NFPA label? NFPA 704 is a labeling system used to identify hazardous materials. It is published by the National Fire Protection Association (NFPA). NFPA 704 is a supplemental labeling system specifically intended for emergency responders, though other people can read and benefit from these labels in normal working conditions.How is NFPA rating calculated? NFPA Rating Criteria and NFPA Labels Different colors represent different types of hazards. A number rating system of 0-4 is provided to rate each of the four hazards and is placed on a placard. 0 represents the least hazardous while 4 represent the most hazardous.