Every day, whether we know it or not, we use a variety of codes. For example, consider a regular traffic light. A green light means GO, a red light means STOP, and a yellow light is a warning to clear the intersection. These color codes are instilled into our memory from a very young age. There are important codes that do not get as much exposure as they should, and they may be just as important as traffic lights when it comes to safety.

There exists a code known as the National Fire Protection Agency’s Fire Diamond. This diamond is a multi-dimensional code that offers people a quick label, or diagram of the potential hazards and dangers of a substance. It is used to tag, label, mark, identify, and notify workers and viewers as to the various degrees and severity of a substance. The diamond is divided into four quadrants, each with a color and a number.

Quadrant Red

This color indicates the level of flammability — flammability is scored on a scale of 0 - 4 where zero represents the least concern and four representing an extremely flammable substance. For example, water, scoring a zero, is least flammable, whereas gasoline, scoring a 3, is very flammable. Other considerations within this section include flash point values, which indicates at what temperature a substance can spontaneously ignite.

Quadrant Blue

This color indicates the level of health risks — potential health risks are scored on a scale of 0 - 4 where zero represents the least concern and four representing something that poses extremely dangerous health risks. For example, ether, scoring a 2, could cause temporary incapacitation and possible residual injury, whereas sarin gas or carbon monoxide exposure, both scoring 4, could cause death or serious residual injury within a very short period of time.

Quadrant Yellow

This color indicates the level of chemical reactivity — chemical reactivity is scored on a a scale of 0 - 4 where zero represents the least reactive and four representing an extremely reactive substance. Substances that do not react with water score a zero, such as helium. A more reactive element like potassium, which undergoes a violent reaction when mixed with water, scores a 2. Nitro glycerin, which is capable of explosions at a normal temperature and pressure, is an example of a substance that scores a 4.

Quadrant White

This color is reserved for special codes that may be particular to a specific substance. These codes range between different jurisdictions, but, generally, may be classified by the following acronyms:

COR, ACID, ALK: Strong Acid or Base

  • BIO: Biological Hazard

  • POI: Poison

  • RA or RAD: Radioactive

  • CYL or CRYO: Cryogenic

These tags are usually supplemented by a larger identifying tag like a radioactive or biohazard sign, and is often clearly marked.

It is never a good idea to assume that a matieral is clearly marked, so consider each aspect of the NFPA Fire Diamond and prepare your PPE accordingly. Ensure that you have the qualifications to handle dangerous goods, and know what you are dealing with before you put yourself or anyone else at risk. Learn the fire diamond, it’s various codes and associated levels of risks and you will always be in the green when it comes to safety.

For more on symbols and signs you should be familiar with both at home and on the job, check out Janitorially Speaking - Knowledge is Safety