CO2 Fire Prevention Safety: NFPA-12 Impacts of Changes

Posted by ORR Protection on Dec 9, 2020 11:58:00 AM

During the MCFP Virtual Conference series, Rick Reynolds, Vice President of Engineering and Training at ORR Protection Systems, talks about the impacts of NFPA-12 changes. Part 3 of 4.

Video Transcript:

Local application. You know, a local application can be a quench tank or a dip tank, what we call. It can be a hood system where we're actually just protecting a wet bench if you will, or something like that. So those are local applications. We have a paint booth as an example, it can be done as a local application environment. So a lot of different local apps— or a roll mill in a steel factory, as an example, we protect a lot of roll mills. Where the actual, only thing we're protecting is that roll mill as the steel's going across the conveyor, and we're using across two roll mills, then we would protect just that area. Well, that's local app. Well CO2 migration, well, life safety comes into play with it as well. So NFPA 12 covers that as well. So it's very important that we take that into consideration.

Impacts of changes: the Normally Occupied Space. It falls into that category. So we have control rooms today that are still protected with CO2. Computer rooms that are, IT rooms, believe it or not. Laboratory rooms, like I was saying. MCCs are normally, I mean, I'll walk into MCCs on a regular basis, especially in the power generation sector. That marketplace they use, they have a lot of motor control centers that are still protected with CO2. And then we're actually upgrading those to a clean agent, a different alternative fuel, I mean, a different alternative suppression system, but they are still protected today with a clean agent with CO2, and we're using alternate suppression means. Electrical switchgear rooms like this picture in here. This is a perfect example of an opportunity there to switch that. Now, the next step is going to be for a normally unoccupied area, but it's occupiable. An example of that may be a turbine enclosure, a cable spread room as it shows there and where you would enter it occasionally, but you could go in it.

This is a different type of a fuel oil room or a lube oil room. But as you can see, you can go in that space. Those two little cylinders there right in front of us, those are filters. So there are times where an associate may need to go in there and change out those filters, or one of your actual team members, and in doing so, they would enter that space, and maybe that's an arm system or a live CO2 system. And so that's really occupiable in a normally unoccupied space, so it can be occupiable, but it's normally unoccupied. So I tried to use this as a video to kind of show you, even though it's really an unoccupied space, an unoccupiable on a regular basis, but it's occupiable. So it's very important to understand what the differences are there.

Then of course this next video is for a totally unoccupiable space. These are really permitted zones. These are permitted areas where we would call it to actually be a permitted, confined space permitted area. So this is an exhaust plenum or a load bearing tunnel is what this is for. And that little bitty room there, that little hatch, that's a load bearing tunnel for a turbine enclosure. And so that, we would actually consider that to be a confined space, but that is still an unoccupiable space where we would not occupy that at all. However, it is still an area that needs to be, um, protected with CO2, but that would actually still fall into what we would call NFTA 12. And that's an impact of change area. So very important to understand that.

Now this is an example of a high pressure system. I've shared a lot about low pressure and the impact of low pressure and kind of explained all the selector valves and all. Well, this actually holds true also on high pressure, no difference really on the high pressure system, you have all the same sequences, if you will. We have a pneumatic German siren. We have a pressure discharge switch. We have audibility, we have a maintenance switch and so forth. So a lot of the same configurational parts and pieces are on a high pressure system, just as well as it is on a low pressure system. So they both come into play on both types of systems. So, it doesn't really matter what type of system it is because both systems actually have the same types of actual systems. If they are. Existing systems there, again, the code, these are code-driven types of system identifiers.

And so here is the retroactivity word that is used in the code NFPA12. And so in what we would call the national fire codes, we really look at two words out there, or there is a should, and then there's a shall. Those two words mean a lot to us that are in the industry and the authorities having jurisdictions that are out here. They are very, very keen on those two words. One of them being should is really kind of a recommendation. It's a recommended practice if you will. Shall is actually, it's a mandate. It's a true requirement. We have to actually take care of that, if you will. And so that is a write-up offense, if you would, shall. Like I said, should, it's just a recommendation and shall is a, is a true offensive thing where we have to actually write that up. So these are all "shalls."

So one through six are "shalls." We shall have proper signage. We shall have stop/maintenance lock-out valves. We shall have discharged pressure switches and pneumatic timers and pre-discharge sirens. And of course, provisions for entry. So the signage, you know, we talked about signage is number one, and signage is the easiest and the fastest way that we can get protection to the space. And this is a warning sign that is actually shown in the bottom right of the screen. And that sign is an older style. Now what they tried to do was because there's so many signs out there, we've got everything from paper signs up on doors, to all kinds of signs that I've seen out in the industry. And I think what we're trying to depict here is that ANSI the American standard Institute, they finally said, you know what, let's get all the signs being the exact same out there.

And so what they NFPA even came across with sponsorship was we want all of our signage to be the same. And so what they did was they said, you can no longer use this warning sign. Like it is now we've got to have what we call the one man lung. Okay. So now when you see the one man lung out there, everybody should automatically, we start registering that, uh, that's CO2. And that's what they tried to do was make it universal across the platform and across the industry for CO2. Now, every time we see that one man lung, we know that hey, it's the toxicity it's actually CO2. We need to back off. We need to look at protection here. So that's what it's all about. It's all about that CO2 toxicity. So that's where the one man lung came in.

So changing out signage immediately is a quick first step into it. So if you've got a CO2 system and you need to start doing some first steps, my recommendation and ORR's recommendation is immediately reach out to them or reach out to your provider and get some signage. That's the easiest step. And there's about five different signs. And I can show you a couple of those, uh, out of the gate, but there's about five different signs that really have to be incorporated on your site. So, uh, but we'll, we'll talk about that just a minute. So maintenance, lockout valves you know, what is the maintenance lockout valve and how does it work work? And what's its main purpose and function. So its main purpose is to prevent an accidental discharge. The whole driven fact behind it is to make sure that we're locking this thing out. If somebody is going to be working in and around the system, they want to make sure that we are actually preventing all of that energy of CO2 going in the space that somebody can be working and that's for all safety aspects.

And so that's the key thing is lock it out, tag it out and make sure nobody's going to get CO2 sprayed on them or in that environment. And so the code change was most systems have a lockout valve on them, and most of them are at the tank level and that's legal, that's a hundred percent of it meets the intent of NFPA. However, the new layer of NFPA in 2005 was see that next bullet point where it says supervision. That's the key factor. Um up until that point supervision wasn't in the actual document. Now we've got to take it into the supervision level. So now supervision must be provided. So now I've got to have that monitoring box at the top. It's one thing to have the locking mechanism, but to have that supervisory block up there that actually has, has electrical connection going back to the panel.

It's very important. Now that that is actually, excuse me, electrically supervised as well. So it has to have both mechanisms on it. It has to have the lockout valve, capable as well to have a lock on it so we can lock it in off position, but it's also has to have the electronic or the electronic notification back as well. So it's a two stage type of valve configuration. Now, if you have multiple zones coming off, like on those low pressure tanks that I was showing you say, if you have one master valve that the tank and it leaves the tank, and it goes out to say four or eight zones coming off of it, and those are selective valves. Well, the code does give us a little bit of, of tolerance and says that as long as you're not going to work on any of those other zones live, you can use that master valve at the tank as the main lockout valve.

Now I've seen some types of companies or some companies out there, and they would say you got to have a lockout valve on every one of those lines. Well, if the client wants to lock out each individual valve and each individual line, that's perfect, no problem. That is an option. However, the code does give us a little bit of tolerance and gives us that capability of only locking out that one valve on the tank. So it does have a little bit of a grace period, if you would, in order to help us and, and costing factor where all we need is that one on the main tank. Now to install that master valve on the main tank, if you don't have it, we do have to bleed the master of the big tank, but, um, that we can work through that and it's not as painful as it may seem. But we do this on a regular basis. So it's not as painful as it may appear.

Discharge pressure switch, you know, what, what would that be used for? Well a discharge pressure switch is mainly used to enunciate the panel that somebody has manually activated this system. And most of our systems out there today have a pneumatic capabilities of being discharged. And then if a system is pneumatically fired, by having a pneumatic, uh, operator on it, and I'll show you in a picture here in just a second, but that pneumatic firing, then we want the actual panel to be able to enunciate the audible circuit. And that's what one of these pneumatic operated pressure switches are for. So if you look at the top that has a input for a pipe to actually apply pressure to a contact switch in there, and then that actually will shut down the dampers or shut down the, the dry process or whatever.

But that's what that's for is so that's a pressure operated switch, and that's a code compliance opportunity as well.

Pneumatic time delay bottles, and times that's what those are. So those are what we call accumulator bottles. So CO2 would accumulate in that bottle and then after it accumulates for over 60 seconds or 30 seconds, whatever the duration is, then once it accumulates so much it back pressures back in, then it would finally fire the actual piston on the actual main discharge line. So those are accumulator bottles to build up pressure until it would finally fire out at the actual piston line. So that's the pneumatic time delays that are required on a system now. So a new feature to a lot of systems out there that do not have pneumatic time delays. So very, very important that we put these and they shall be provided.

So that is a "shall be" provided pneumatic pre discharge sirens on that discharge that I showed you that video. You heard that siren come up to, uh, the, uh, the loud noise after the electronic audible. That's what that was. You'll see the connection point on the bottom left of that siren. There's just a pipe that goes from they, whenever that pneumatic tube, then I showed you that tank was filling up while it's filling up. There's a T that goes out and it has that siren, that siren, and that tube is filling up at the exact same time. So while it's filling, that siren is also, spinning at the same time, creating that noise. And so that's about 90 to 110 DB 10 feet away from it, very loud. And it's in the space for enunciation to have people evacuate. Again NFPA required, "shall be" provided in the space.

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