What is the Safety Diamond and what is it for?

It is also known as the NFPA Code 704 (National Fire Protection Association), and was originally devised to guide the personnel of the fire brigades.

It is mandatory for chemical substances containers and must be present in industrial, commercial and institutional facilities that manufacture, process, use or store hazardous materials.

It is not mandatory in transport units nor is it intended to be known to the general public. The NFPA established standards known as the National Fire Codes, which recommend safe practices for fire control and this diamond is part of those codes.

This new symbol will not apply to:

  • Pharmaceutical products
  • Food Additives
  • Cosmetics
  • Pesticide residues in food

What is the safety diamond for?

The fact of indicating the level of danger of a substance, also serves to:

  • Easily distinguish dangerous products.
  • Quickly report the nature of the risk posed by the product.
  • Facilitate rescue or relief efforts in cases of emergency.
  • Caring for the lives of those who help in emergencies.
  • Provide guidance information for the time of cleaning and removal of the substance.

Safety diamond features

The safety diamond is made up of 4 diamonds arranged in the following order:


It means that the substance poses a health risk.

And the scale reads like this:

0 = no risk : This code is used on low-risk materials in fire conditions, such as sodium chloride.

1 = Slightly hazardous: These are materials that only cause minor residual damage, even without medical treatment, such as glycerin.

2 = Dangerous : It is the code assigned to those materials that can cause temporary disability or permanent damage, in case of continuous exposure, such as chloroform.

3 = Extremely dangerous: These are materials that can cause temporary or permanent damage even with little exposure. Potassium hydroxide is an example of this type of substance.


It means that the substance represents a fire hazard. That is, it is flammable or it can be. Its scale means:

0 = Does not burn

This is the case of substances that do not burn, even when they are exposed for more than 5 minutes to temperatures of 815 ° C, such as water.

1 = Burns at 93 ° Celsius

These types of materials require a kind of preheating for ignition to occur. A flash point is calculated at 93 ° C.

2 = Ignites below 93 ° Celsius

They do not require very high temperatures to reach the ignition point, which ranges between 38 ° C and 93 ° C. Petrodiesel is an example of this substance.

3 = Ignites below 37 ° Celsius

This code is assigned to those materials that can ignite in almost any ambient temperature, such as gasoline.

4 = Ignites below 25 ° Celsius

These are substances such as propane, which vaporize at ambient atmospheric pressure or burn easily in air (less than 23 ° C).


The diamond of this color indicates that the substance represents a reactive hazard. Regarding the scale of this rhombus, the meaning is as follows:

0 = Stable:  It is a material that remains stable even under exposure to fire. Helium is a good example.

1 = Unstable if heated:  It is a material that can be unstable at high temperatures and pressure. For example, acetylene.

2 = Possibility of change:  Substances that can react violently with water or with high temperatures and pressure. Phosphorus is one of the substances that falls into this category.

3 = It can detonate with shock or heating: It  can detonate with an ignition source, such as water or a strong electrical discharge, such as fluorine, for example.

4 = Can detonate easily:  Tends to detonate very easily. This is the case of nitroglycerin, for example.


It is the color used for substances that constitute a very specific risk. In this case, the scale code is not made of numbers but of letters and they mean:

  • OX = oxidizing materials such as potassium perchlorate.
  • ACID = acid substances.
  • ALC = alkaline materials.
  • COR = corrosive materials
  • W = refers to substances that react with water in a dangerous way, such as sodium cyanide.
  • R = is the letter used for radiation material such as plutonium.
  • BIO = refers to biological risk. It is used in case of viruses.
  • CRYO = means that you are dealing with cryogenic material.
  • Xn Harmful = presents epidemiological or significant spread risks.

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