CO2 Fire Prevention Safety: Compliance and Exposure Limits

Posted by ORR Protection on Dec 2, 2020 1:00:00 PM

During the MCFP Virtual Conference series, Rick Reynolds, Vice President of Engineering and Training at ORR Protection Systems, discusses CO2 Safety, NFPA 12 Life Safety Compliance, LPCO2 Systems, CO2 Agent Exposure Limits and other CO2 Safety concerns. Part 1 of 4.

Video Transcript:

Hello, and welcome to the MCFP Mission Critical Fire Protection Show. I'm Rick Reynolds, the Vice President of ORR Protection Systems. Today, we're going to be talking about numerous things. I get to highlight the CO2 "Safety" and NFPA Life Safety "Compliance." The NFPA 12 is what we call the CO2 code. So today we're going to highlight all of the aspects of NFPA 12. And NFPA 12 in 2005, there's a big dynamic change in the code. And that actually is retroactive for all CO2 systems. So today we're going to talk about some CO2 safety and also what that impact is made for the industry. So without further ado, let's get into it, and let's start talking about some of the things about CO2. But before we go too far, let's talk about the impact and what CO2 or how CO2 actually works on a fire. As you're seeing on the graph there, CO2 and the fire triangle that we learned from many, many years ago, the fire triangle is still in existence today.

You got to have oxygen, you've got to have heat, and you've got to have a fuel source. And then you have to have a chain reaction in order for all of these elements to actually work in order in a controlled environment or a chain reaction for that actually to take place. And then in doing that, if you remove one of the fire triangles, then we do know that that would actually suppress the fire or the fire would go out. Now, CO2 has some very, very unique properties. It can actually reduce the actual fire by actually reducing the CO2 in the area by displacing oxygen. And it can actually reduce the actual fuel vapor in the air because when it discharges it actually displaces, and it actually has a molecular structure that actually contains the fuel vapor in the air. But also as all of us know that CO2 is also dry ice.

So that actually cools the environment as well. So it has a cooling effect. So it actually can atomize or reduce the fuel vapor by reducing the fuel. It can remove that side of the triangle. It can remove the heat by cooling it because we do know it's a very cold agent and then also it can displace oxygen. So CO2 is a very good firefighting agent out there in the industry. And that's why it's so used so readily available. And so well used in today's time. A lot of power generation customers still use it today. And it's a very vital product in today's marketplace when we talk about fire protection. Now, whenever we talk about it in fire protection, though, there's a lot of safety elements that we've got to take into consideration. And so we're going to talk about a lot of those safety elements. But before do, let's talk about the versatility of CO2.

Now the image that we have on the screen now is the versatility. The red tank, there is what we call a bulk or a CO2 storage tank, a bulk CO2 storage tank. Now that storage tank actually has bulk CO2 stored in it as a liquid. And that CO2 then is actually conditioned or cooled. And it has it cooled where we can actually use multiple piping networks coming off of it. And we can use selector valves and those selector valves can then actually go out to individual hazards. I'll actually give you identifiers of where we can actually send that out to, or a conventional system or a high pressure CO2 system. It may actually only be able to shoot CO2 into one zone, one hazard or one area. And then after it actually sends it out to that one area, if you will, you would have to recharge those high pressure bottles each individual time.

Well, the benefit of a low pressure system and that storage vessel, like you see there, is that we can actually design the system where it can have multiple what we call multiple shots or multiple zones of discharge. So we would discharge the system as an example for that fuel or that hydraulic sled there, or that hydraulic unit. And we would discharge it once. And then we would discharge it again if need be, we can have multiple shots or multiple discharges in one area. So that's the benefit of a bulk CO2 system. And another benefit is where we would just have a truck come in. And then that truck would back up and they bulk storage. They would fill up that and then we'd be on our way. Instead of pulling out all of the bottles, a system this size with a bulk, you can get up to like a 12 ton unit or an eight ton unit, a four ton unit.

Can you imagine each of the, the largest size of a CO2 high pressure cylinder is about a hundred pound cylinder? So you think how many on a 12 ton system, how many bottles does that hold? We'd fill up that whole yard there in order to do that. So the versatility of low pressure, when you start getting into power generation, is really, really good for that application. And that's why it's so widely used in that it's widely used and also the roll mill or an industrial application. We use a lot of it in those applications. So a lot of specialty types of industrial application, we use CO2 and it's still used today in a very, very wide setting. But when we use CO2, we've got to take a lot into consideration and then NFTA 12, they actually, in the annex of 12, we started looking at the actual exposure limits.

Now this chart is kind of tough to read because it's so small, but one of the things I want you to look at is on the left-hand side is the percent of CO2 in the air and the consequences or the effects of CO2. And then in the middle is the duration of time that you may be exposed to that concentration or to that percent of CO2 in the air. And when you see those concentrations in that exposure, and then those effects it really, really, you got to always take into consideration the risk and the gain of using CO2. CO2 is a very economical system to use. But also we got to take into consideration the exposure risk. And I don't want to actually minimize the risk whenever we're talking about CO2, we always want to have that in mind, whenever we're using CO2, our team members are always, always taking that into consideration.

When we're servicing systems, we're putting flagging tape around, we're actually sealing off the area to make sure everybody's protected when we're in those environments. So it's very, very important that you're always looking at that even the minimum, even the minimum of 2% or 3%, you always have to take that into consideration. When you look at actually some of the durations there, some of the minimals that you would see there, if you're at 3%, even at three, 3% at a dilution rate, you'll start getting nauseated, you'll start getting dizzy. You'll start actually having the possibility of passing out. Look at it, at 8%, at 6%, you'll start having tremors. So, and you'll start getting headaches and you'll actually start getting some other things.

Well, in a normal power generation setting the percent of concentration that is required in a CO2 environment. Now a base CO2 system, no matter what the actual environment, NFPA 12, the CO2 code that we were talking about, it actually has the base concentration for all systems at 34%. Now, when we start talking about lube oil skids, we're talking about turbine packages, we're talking about electrical packages, look at the concentrations that are minimals. So these minimals are based on the hazards that we're protecting. So an electrical hazard you'll see is 50%. Well, the reason for that is the amount of density of hardware that's in the space. A lot of plastics, a lot of density, plastics, a lot of very, very hard to reach types. So you run into what we call a deep seated fire. So they want to have a higher concentration in those areas. But even at those, you see the 36%, you see the 50% then look at our percent of error.

So you see really, really quick that we can run into a percent of air versus an effect. So we'll run into a high concentration, high effect. So you got to take CO2 safety into consideration. Now this chart came from the Compressed Gas Association or the CGA, if you will. Now CGA comes out, and what I was trying to show is that we've got a couple, I got one more chart here behind this one. And so NFPA comes out and they gave their information. CGA, which is Compressed Gas Association, they came out and they gave another one. Now what I highlighted here is that 15% you actually start having tremors at one minute of concentration exposure, one minute. Now, if you remember on that previous slide, we said at 36% is what we typically protect a lube oil skin. So in a power generation customer that may be watching this, or listening to this or involved in this, you can see only one minute of an exposure and you're going to be actually the possibility of tremors and having some adverse effects.

And then you become unconscious at 20 and 30% at only 30 seconds. And so you really, really have to be careful because of the high concentrations that we may be dealing with in some of these environments. I look at this next slide, this next slide came back from the International Journal of Emergency Medicine. Now this was actually just published in 2017. So we're not talking about old data. A lot of times people, when they're giving presentations about CO2, because CO2 was such an old agent and it's been around for so long, a lot of people pull up old data from way, way, way back. And I understand that I've been in the business, like I said, for a long time, you know, even working before ORR I was in the business. And I think it's important that we don't pull up old data and we share the statistical data from old.

This is 2017, April 4th of 2017. And so as you read this, you can see that some of the risk associated with this. Well, this next part of the slide, is the most disturbing. In 1980, it showed that there were 89 deaths per year in the US alone. And that's in 1980. Now you would think, well, Rick, that's old data and it is old data. I'll give you that. However, what we don't want to, you know, not look at is the next section. And OSHA, which is the Occupational Safety and Health Administration, they came back and said, "Hey, in 2015, we're still well seeing that the estimated number of deaths because of confined space or because of CO2 deaths is still averaging around 90 per year." 90. This is a real problem that we still have around CO2. NFPA did some massive, massive undertaking in order to help prevent this.

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