You can’t if you are using dry chemical extinguishers but you can if you are using foam extinguishers. This is allowed in NFPA 10 Section 3-3.2 exceptions 1 and 2.

Dry chemical extinguishers have no “securement" capabilities. When using a dry chemical extinguisher on flammable liquids, the operator(s) will either put out all of the fire or none of it. It is impossible to put out half of the fire and go get another dry chemical extinguisher to put out the other half; the fire will reflash over the entire surface area.

Dry Chemical is also “application sensitive” meaning that it doesn’t matter how much you apply to the fire, it won’t go out if the dry chemical was not applied properly. We have seen one person put out a 60 square foot pit fire three times with a single 20 lb. dry chemical extinguisher. We have also seen four people each with a 30 lb. dry chemical attack the same fire simultaneously and fail to put it out (not once but three times!). If you don’t use dry chemical properly on a flammable liquid fire, it won’t matter how much you have; the fire won’t go out.

Foam is “user friendly” meaning that as long as it is put on the fire in nearly any manner (in the case of hydrocarbons) some success will be accomplished. Foam does have some “securement” capabilities. Foam puts out a flammable liquid fire by securing the vapors coming off the fuel and separating them from the ignition source and surrounding air. This makes it possible to put out a portion of the fire and use a second foam extinguisher to extinguish the rest.