Today is the day for the inspection of fire extinguishers (the fire extinguishers originally required a monthly inspection, and now the fire extinguishers required a semi-monthly inspection), because the most used fire extinguishers we have ever used are dry powder extinguishers and carbon dioxide. For dry powder extinguishers, we do not need to know the composition of dry powder, just know how to use it. I estimate that this dry powder extinguis