You probably don’t spend much time thinking about the pressure gauge on your fire extinguisher. It hangs on the wall, the needle points somewhere, and as long as nobody has needed to use it, everything must be fine… right? Not necessarily. Knowing what that little gauge means can help you make sure your extinguisher is ready to do its job when you need it most.
Fire Extinguisher Gauges
On most fire extinguishers manufactured within the last three decades you’ll find a pressure gauge with a green area in the middle and red areas on either side. This gauge is one way you can tell whether an extinguisher is charged or not. It’s a pretty simple concept:
Green = good to go!
Red = no go!
If the needle is sitting comfortably within the green “charged” area, the extinguisher is showing that it has the appropriate pressure to operate. If the needle has moved into the red area, that’s a different story.
Depending on the gauge, the red areas may indicate “discharged” or “overcharged.” One side means there isn’t enough pressure; the other means there is too much. Neither is where you want your extinguisher to be. An extinguisher that is undercharged may not discharge properly when you need it while an overcharged extinguisher may discharge too quickly or explosively. *An extinguisher which is “overcharged” is much safer and more functional than an extinguishers that is “not charged.”
Older Fire Extinguisher Gauges
As we mentioned above, only somewhat recent extinguishers will have this green and red combination on the extinguisher’s gauge. Older fire extinguishers, pre-1990, may use other color combinations like blue and red and will frequently have much larger diameter gauges than modern extinguishers.
An extinguisher with this type of gauge, even if it shows a positive charge, should NOT be trusted. Most extinguishers with gauges manufactured before 1984 no longer meet the standards set by NFPA10 to operate as trusted fire safety products.
Reading a Fire Extinguisher Gauge
Gauges can be hard to see and even harder to decipher. Age, weather conditions, and temperature can all play tricks with these devices. A gauge can give misleading readings based on the humidity or if looked at on an angle. For the best results, make sure to always read gauges from straight on, looking at the gauge at eye level NOT over the top or to the side.
Aside from color, all gauges will also have written markers to indicate pressure. You may see words such as:
- Overcharged
- Charged
- Discharged
- Recharge
Only “Charged” or “Fully Charged” mean that the extinguisher can be trusted to function properly. “Overcharged,” “Discharged,” and “Recharge” all indicated that the extinguisher is not in proper working order and should not be used.
Some extinguishers will have a “recharge after use” or “recharge if not in green” towards the bottom of their gauge. You may also note that certain extinguishers, often those sold cheaply in big box stores, have “discard after use” instead.
Fire Extinguishers Without Gauges
Not every fire extinguisher has a pressure gauge. Some types of extinguishers, such as carbon dioxide fire extinguishers, don’t use a traditional pressure gauge to indicate whether they are properly charged. Instead, their charge is determined by weight and physical appearance. These extinguishers contain gases held at such high pressures that a gauge cannot be installed on the unit; for that same reason, these extinguishers are always made with steel rather than aluminum shells.
In the case of an extinguisher without a pressure gauge, prior knowledge of the extinguishers charged weight is needed to determine whether or not the extinguisher can be trusted. Those relying on CO2 extinguishers should familiarize themselves with the weight of these extinguishers by feel alone as there will not be another way to determine readiness in case of emergency. These extinguishers should never be trusted to function properly if their tamper seal is missing; missing tamper seals indicate that the extinguisher may have been used before.
Carbon dioxide extinguishers are considered a specialty fire extinguisher, as such these extinguishers are rarely used by individuals at home. They are most commonly found in commercial settings near electrical and/or sensitive equipment, or around flammable liquid storage areas, or area metal working operations. For example, you might find a CO2 extinguisher in a machining shop or nearby an electrical panel at a factory.
More Than Just a Gauge
Just because your extinguisher is showing in the green or reads “charged,” or weighs the correct amount does not mean that the extinguisher is totally trustworthy. Other components may need maintenance even though the gauge still appears normal. A clogged hose or comprised shell could spell disaster in an emergency. That is why sticking to a regular maintenance schedule, even for home use extinguishers, is so important.
If you’re extinguisher has not undergone the required services or been evaluated for physical condition within the last six years it should NOT be trusted. Extinguishers in commercial spaces such as at a restaurant or in a hotel, are required to be checked by professionals on a yearly basis. As such, we trust that the extinguishers around us in public spaces, if they are “in the green,” are, in fact, trustworthy and ready to assist us.
Fire Extinguisher Guage in the Red
If you find that your extinguisher is not charged, it’s gauge reads in the red or “recharge,” do NOT ignore this. Similarly, if your extinguisher shows as overcharged or feels underweight, do NOT shrug it off. Have the extinguisher evaluated by a qualified fire extinguisher service professional right away. They can determine why the pressure is incorrect and whether the extinguisher needs to be recharged, repaired, or replaced.
Never try to recharge or repair a fire extinguisher without the proper equipment, chemicals, and PPE.
If you are ever unsure of whether an extinguisher is charged or not, it’s best to seek a professional opinion first! The same goes if you are unsure about the physical condition of your extinguisher. Ask before you have an emergency! Practicing the PASS extinguishing method with a real fire extinguisher before an emergency can be beneficial as well.
Key Takeaways
- Gauges that show in the green area and/or say “charged” can be considered as such
- Gauges that show in the red area and/or say “discharged,” “overcharged,” or the like should NOT be evaluated by a professional ASAP
- Extinguishers made before 1984 should be evaluated by a professional even if they still show a positive charge
- Determining the charge of an extinguisher without a gauge is done by weight & physical appearance
- All fire extinguishers should be kept on a regular maintenance schedule to ensure their trustworthiness in the event of an emergency
Disclaimer: This blog post was created, in part, by AI.
