What does NFPA 704 mean

What does NFPA 704 mean? NFPA 704 is the American standard that explains the “hazardous materials diamond “established by the National Fire Protection Association, used to communicate the hazards of hazardous materials. The NFPA 704 standard is the one that helps us identify and classify the different types of chemical substances, “whether for transport or storage”, providing basic information about the dangers that compose it, through special visual methods “colour and shapes” and numbers.

What does NFPA 704 mean? is explained by a diamond made up of 4 colours, whose risk is identified with a numerical scale, where 0 expresses that there is no risk and 4 that the risk is very high. These notices act as an immediate warning system for handling personnel, addressing “blue” health, “red” flammability, “yellow” instability, and “white” special hazards that may be present.

What does NFPA 704 mean – emergency response

NFPA 704 provides a simple, easily recognizable, and easy-to-understand system for identifying specific hazards of a material and the severity of the hazard that would occur during an emergency response. 

The best source of information for the classification of chemicals under NFPA 704 is the product safety data sheets that manufacturers and suppliers are required to have. Other sources of information are guides produced by specialized relief agencies.

This standard will provide a simple, easily recognizable and understandable system of identification to give an overview of the hazards of a material and the severity of these hazards for emergency response.

  • Easily distinguish dangerous products.
  • Quickly report the nature of the risk that the product represents.
  • Facilitate rescue or aid work in cases of emergency.
  • Take care of the lives of those who assist in emergencies.
  • Give guiding information for the moment of cleaning and removal of the substance.

What are the advantages of the NFPA diamond?

Because it applies to any type of industrial, commercial and institutional facility that processes, stores or markets chemical substances. Its main objective is to provide the necessary information to people who handle substances and to relief and emergency response agencies. They can assist in the planning of fire control and emergency operations, including cleanup. 

What does NFPA 704 mean
What does NFPA 704 mean

It establishes through a rhombus sectioned into four parts of different colours, to indicate the degrees of the danger of the substance to be classified. The system consists of assigning colours and numbers, and giving a “classification” to a product, managing a scale from 0 to 4, depending on the degree of its danger. Each of these hazards is associated with a specific colour.

What does 4 represent in the NFPA 704 diamond?

The four divisions have colours associated with meaning.

  1. Blue refers to health risks
  2. Red indicates a flammability hazard
  3. Yellow indicates the risks due to reactivity: that is, the instability of the product.
  4. These three divisions are assigned a number from 0 (no danger) to 4 (maximum danger).

In the white section, there may be special indications for some materials, indicating that they are oxidizing and acidic, alkaline, corrosive, water reactive or radioactive.

 Health Risks

It refers to the ability of a material to cause damage to health through contact or entry into the body through different routes of entry, such as inhalation, ingestion and skin contact. Damage to health resulting from the heat of the fire or due to the force of the shock wave from an explosion is not considered in this system.

Degree of Danger

  • 4 Deadly: Materials that, under emergency conditions, can be lethal. The element that, with a very short exposure, can cause death or permanent damage, even in case of immediate medical attention. For example, hydrogen cyanide
  • 3 Very Dangerous: Materials that, under emergency conditions, can cause serious or permanent injury even if medical attention is given, such as potassium hydroxide.
  • 2 Dangerous: Materials that, under emergency conditions, may cause temporary disability or residual injury unless prompt medical treatment is given, such as chloroform or caffeine. 
  • 1 Little Dangerous: Materials that, under emergency conditions, can cause significant irritation but only minor residual damage even in the absence of medical treatment. An example is glycerin. 
  • 0 No risk: Materials that, under emergency conditions, would not offer a hazard beyond that of ordinary combustible materials, in case of ingestion or inhalation in considerable doses, such as sodium chloride. 

Flammability Hazard

Flammability refers to the degree of susceptibility of materials to burn. Some materials can burn under some specific conditions, but will not under others, the form or condition of the material must be considered as all its inherent properties.

What does NFPA 704 mean
What does NFPA 704 mean

Risk of fire

  • 4 – They have a flash point below 23°C (73°F). . Materials that will vaporize rapidly or completely at normal atmospheric pressure and room temperature or that are rapidly dispersed in air and will burn readily.
  • 3 – They have a flash point between 23°C (73°F) and 38°C (100°F). Liquids and solids can ignite under almost any ambient temperature condition. Materials in this classification produce hazardous atmospheres with air under almost all ambient temperatures or, although unaffected by ambient temperatures, ignite rapidly under almost all conditions.
  • 2 – Its flash point ranges from 38°C (100°F) to 94°C (200°F). Materials in this grade under normal conditions would not form hazardous air atmospheres, but under high ambient temperatures or moderate heating, they could release vapour in quantities sufficient to produce hazardous air atmospheres.
  • 1– The flash point is greater than 94°C (200°F). Materials must be preheated before ignition can occur. Materials in this grade require considerable preheating, under all ambient temperature conditions, before ignition and combustion can occur.
  • 0 – Does not catch fire. Materials that will not burn under typical fire conditions, including inherently non-combustible materials such as concrete, stone, and sand water or exposed to a temperature of 94°C (200ºF) for more than 5 minutes.

Instability Risk

Instability refers to the intrinsic susceptibility of materials to release energy. It applies to all those materials capable of rapidly releasing energy by themselves through self-reaction or polymerization. 

Degree of Danger

  • 4 – Can easily explode. Materials that in themselves are readily capable of detonation or explosive decomposition or explosive reaction at normal temperatures and pressures (e.g., nitroglycerin, RDX).
  • 3 – May explode if shocked or heated.
  • 2 – Unstable in case of violent chemical change. Materials that readily undergo a violent chemical change at elevated temperatures and pressures. Reacts violently with water, or can form explosive mixtures with water (e.g., phosphorus, potassium compounds, and sodium compounds).
  • 1 – Unstable if heated.
  • 0 – Stable.

What does the colour white indicate on an NFPA 704 marker?

Special hazards refer to reactivity with water, oxidizing properties of materials causing special problems, and alkaline substances.

What does NFPA 704 mean
What does NFPA 704 mean

Degree of Danger

OX: Materials that have oxidizing properties. Reacts with water in unusual or dangerous ways, such as sodium cyanide or sodium. Highly oxidizing material that can cause the combustion of other materials without the presence of air. For example, potassium perchlorate and hydrogen peroxide.

W: Materials that react violently with water or explosively. Oxidizers, such as potassium perchlorate.

SA: Gaseous materials that are simple asphyxiates. Limited for gases: nitrogen, helium, neon, argon, krypton and xenon.

The symbols: –W, OX, and SA are officially recognized by NFPA 704, but symbols with obvious meanings such as those noted are occasionally used. The following acronyms and symbols are not included in the NFPA 704 standard but are used relatively frequently:

  • COR or CORR: corrosive materials, usually strong acids and bases.
  • ACID: strong acids. For example, sulfuric acid.
  • ALK: strong bases (alkalis). For example, potassium hydroxide.
  • BIO: Biological material or with biological residues that pose a risk of transmission of pathogens. For example, hospital material and bacterial cultures.
  • RA, RAD: radioactive material. For example, plutonium and uranium.
  • CYL or CRYO: cryogenic material. For example, liquid nitrogen.
  • POI: poisonous substances (from English poison). For example, arsenic and strychnine.

What is the difference between GHS values and NFPA values?

The NFPA 704 standard and the OSHA Hazard Communication Standard were developed for different purposes. Now that OSHA has adopted GHS both systems involve numbers which lead to many questions about how the two number systems are related.

NFPA 704 is widely used and recognized by fire and emergency services. Safety personnel to identify the hazards of acute/short-term exposure to materials under conditions of fire, spill, or similar emergencies.

What does NFPA 704 mean
What does NFPA 704 mean

OSHA’s recent addition of the Globally Harmonized System (GHS) into its HCS. It is important to note that the GHS numbers are not relative ratings of hazards, but rather are used to classify hazards for proper labelling and training information. These GHS numbers are not relative hazard ratings and, have an inverse number of systems with 1 being the most hazardous and 4 being the least hazardous.

NFPA 704

HazCom 2012


0-4 = 0-least hazardous, 4-most hazardous

1-4 = 1-most severe hazard, 4-least severe hazard

The Hazard category numbers are NOT required to be on labels but are required on SDSs

  • Health-Blue
  • Flammability-Red
  • Instability-Yellow
  • Special Hazards*-White *OX Oxidizers W Water Reactive, SA, Simple Asphyxiate
  • Product Identifier
  • Signal Word
  • Hazard Statement(s)
  • Pictogram(s)
  • Precautionary statement(s)
Flammability in the red section Instability in the yellow section etc.A broad range of physical hazard classes is listed on the label including explosives, flammables, oxidizers, reactive, pyrophoric, combustible dust and corrosives.

Health and safety-related topics:

  1. 5 types of workplace hazards
  2. Safety of work at height
  3. Health and safety training
  4. Welding safety precautions
  5. Incident investigation method
  6. Electrical safety hazard
  7. Sabic safety officer interview questions



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