Insight to Understanding Flammable Gas Limits
Visitors to our websites often search for details on combustible or flammable gases since leaks and exposures of this gas type have created some of the most catastrophic industry events. We will post a series of articles helping to better explain the differences between flammability and combustibility, explosive limits, as well as present a gas tables for reference.
What is a Flammability Limit?
The amount of combustible gas in an air mixture when the mixture is flammable is known as the flammability limit or flammable limit. Gas mixtures that consist of combustible, oxidizing, or inert gases are only flammable under certain conditions. The lower flammability limit (LFL) identifies the smallest mixture able to sustain a flame. The upper flammable limit (UFL) identifies the richest flammable mixture.
A quantifiable difference exists between the flammability limit and explosive limit. In specialized process applications such as combustion engines, achieving the perfect combustible or explosive mixture is important. However, in engineering a gas detection system, the flammable gas cloud is turbulent and the exact mixture can greatly vary. As such, many professionals interchange the term flammability limit (UFL/LFL) and explosive limit (UEL/LEL) depending on their education or geographic location.