Carbon Dioxide (CO2) systems are one of the oldest types of gaseous fire suppression systems. CO2 is very inexpensive, requires no cleanup, and can be applied to a broad range of fire hazards. The major disadvantage associated with CO2 systems is that the concentration required to extinguish a fire will not support human life, and for this reason, it can no longer be used in occupied enclosures. In this video, fire protection expert Lee Kaiser discusses the history of CO2 systems, their major characteristics and the applications they are most commonly used for.
CO2 SYSTEMS, THE ORIGINAL CLEAN AGENT
Lee: "The first gaseous system that we're going to talk about this morning is CO2 systems, or carbon dioxide systems. We use CO2 to extinguish fires. CO2 systems, we like to call the original clean agent. They're gaseous like clean agents, and there is no cleanup, so we've been using CO2 systems longer than any other system type out there of the gaseous system variety. Big range of applications. In the 1960s companies that made CO2 systems had a lot of money to develop applications for them, so we have a really broad range of fire hazards that we can apply CO2 systems to extinguish fires with them, and we can just apply it in a lot of places that we don't have applications developed for with other agents.
CHARACTERISTICS OF CO2 SYSTEMS
Some of the characteristics, very inexpensive systems. CO2 is extracted from alcohol production, and we have ways to get to that CO2 and capture it for fire protection use. Fast extinguishment, very fast extinguishment. We can extinguish fires with CO2 systems in typically less than 30 seconds, so just a hair slower than dry chem systems. Extinguishes fires via cooling, and because it's a gaseous system it penetrates shielded enclosures, so if you have a cabinet that it has ways for gas to get in there. It's not all sealed up. The fire could be in the cabinet, and that CO2 system can work its way into there and cool that fire and extinguish it.
EXTINGUISHING CONCENTRATIONS ARE DANGEROUS TO HUMANS
The major disadvantage of a carbon dioxide system is that the extinguishing concentrations will not support human life. So it'll kill you. And that's really something you have to be aware of when you work around a CO2 system or you're getting ready to specify or install one. The code for CO2 systems is NFPA 12, and so NFPA 12 now says, over the last few years it's been changed that it can be no longer used for normally occupied enclosures.
Total flood systems in an occupied enclosure, it's not available for use. You need to choose some other alternative system, and then also there are safety devices and retrofits of a system that are mandatory to do on carbon dioxide systems. We'll talk a little bit more of that in a second.
WHY ARE CO2 SYSTEMS STILL IN USE?
But why do we still use it? If it's going to kill you, why do we still use CO2? Well, here's the deal. Sometimes it's the only way to protect a hazard. Because of all the development that was done, and because of some high-challenge fire conditions, CO2 systems may be the only way to extinguish a fire. Now, in addition to that, we use CO2 systems for buildings that have a lot of fires. There are some facilities that will have a fire every day, every week, and they're used to working around their CO2 system. They're used to having fires, and when the fire happens, they just hit the button, discharge the system, and then after a predetermined time it stops, or when the heat goes down it stops after it's put out the fire.
With that, you're going to consume a lot of CO2, so every month the trailer backs up and fills this outdoor bulk tank with CO2 just for you to keep on doing your thing and keep extinguishing the fires that you expect to have inside of your type of facility. We see that a lot in manufacturing, and steel production is one major place that they have a lot of fires and use low-pressure bulk CO2 systems."