What are the three zones of a fire extinguisher? What do they mean by the three zones?
The three areas are high pressure, normal pressure and normal pressure. Take a look at the purchase! If the pressure is low, then don't buy it. Of course, the pressure can not be too high.
Periodically check the pressure gauge for a long time to see if the pressure is in the low pressure zone. If you come to the low pressure zone, then the fire extinguisher is invalid. There is not enough pressure to eject the extinguishing substance!
Fire extinguisher pressure gauge in three colors are yellow, green and red, they reflect the content is not the same: Yellow said the pressure is too high, excessive pressure, but can be used; Green said the pressure is normal, normal use; red indicates insufficient pressure, under pressure, not normal use.
