Flammable gas as defined by the DOT is any compressed gas that either forms a flammable mixture with air at a concentration of less than 13% by volume, or has a flammable range in air wider than 12%, regardless of the lower explosive limit (LEL).

• DOT对易燃气体的定义是：在体积浓度小于13%25的情况下同空气形成易燃混合物的任何压缩气体，或者不考虑较低的爆炸极限（LEL），在空气中的易燃范围大于12%25的任何压缩气体。