Understanding the Flammable Triangle and Flammability Limits

Understanding the Flammable Triangle and Flammability Limits


FlammabilityWhat exactly is “the flammable triangle?” The term is a nickname for flammability diagrams that refer to the composition of gas in the air of an environment. Certain combinations of gases in the air can lead to a risk of ignition and fire.

The Flammable Triangle speaks of a range in which ignition is most likely. It has a lower flammability limit and upper flammability limit. Different gases possess different concentrations which mark their lower and upper flammability limits. Depending on the environment and gases being discussed, flammability can be defined anywhere from ignition that sparks a fire, through to full explosions.

The lower limit speaks of environments in which there isn’t enough gas for an ignition or explosion to burn if the air comes into contact with an ignition source such as a flame. The upper limit refers to an environment that is too rich in these gases to produce ignition or explosion if it comes into contact with an ignition source.

These lower and upper limits are also affected by temperature and pressure, and will not always result in the same type of ignition. All of these factors contribute to the range in which The Flammable Triangle exists in a particular environment.

In application, such limits must be understood and constantly measured by workers in environments ranging from tanker ships to mines. Explosive atmospheres are controlled using a range of methods. Non-reactive gases such as nitrogen and argon are sometimes introduced into an environment at rates that quell combustion chances. Another option is to use scrubbers or resins that absorb flammable and explosive gases.

Of course, these environments must all be constantly measured in order to know what controls should be introduced to an environment and what risk there is to personnel and equipment inside the environment. Oxygen analyzers are used to monitor and control the purity of gases. Whether it’s a flammable gas whose limits must be monitored, an oxidizer (usually oxygen) that helps fire spread, or a control gas used to decrease concentration of another gas, oxygen analyzers can measure them all and help to monitor and control environments so they can stay as safe as possible. Talk to us about any other needs you have in helping to monitor these environments and keep them safe.