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NOTES & SUMMARY
CODE & STANDARD REFERENCES
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TRANSCRIPT
How to Determine an Occupancy Hazard Classification?
INTRODUCTION So, how do we determine an occupancy hazard classification? So far in this arena, we've talked about what an occupancy hazard classification is, why it's important and who is responsible for determining it. But how is an occupancy hazard classification actually determined? WHAT IMPACTS AN OCCUPANCY HAZARD CLASSIFICATION? Well, we've alluded to it earlier, the occupancy hazard classification, or I'll just call it a hazard classification in this module. Well, it's determined by: (1) the Combustibility of the products (2) the Quantity of the products (3) the Height of the products Basically, it's a way to describe the fuel load and the fire intensity for a space. What we don't consider here as part of this determination is the likelihood of a fire starting. We're designing an automatic fire sprinkler system that's gonna protect against a fire. So, some of our inherent assumption is that a fire has already started in the space that we're looking at. We're just trying to design a system to control or suppress that fire. WHY SHOULD I CARE? Okay, Joe, but you said in the last video that the professional engineer is responsible for the hazard classification. Well, if that's not me, why should I care? Well, you should care. As a designer, layout tech, intern, plan reviewer, estimator, inspector, or anything other than a professional engineer, it's still important to understand how these are determined. There are times when engineers don't fulfill their obligation. Ooh, big shock, right? There are bad sets of bid documents. There's also times, like in the example in our last video, where the PE did put together the hazard classification, but we should be questioning what that determination was. We need to know how that determination's made what the process is. So that even in situations where it's made, we can make sure it's right. Fine - so how do we go about figuring out a hazard classification? STEP #1: EVALUATE EACH SPACE Well first, we look through the different areas of our building and the descriptions for those areas. What we're wanting to do is get familiar with the proposed building and what we reasonably think is going to be put inside of it. For most areas in say, light commercial or residential structures, the hazard classifications won't actually be that controversial. They're important, but they won't be that controversial. Each area has a different fuel load or fire intensity. And we evaluate it separately. I say area because it's not a room or a building that we have to consider as one. It's each individual space. Here really, I'm looking at each area as a fire would, as a fire would burn. At the end of the day, we're trying to see where an area best matches the examples that are given at NFPA 13. We're trying to find how our area best aligns with the examples that we're given. Would that space have a fire where the quantity and the combustibility is relatively low? Relatively tame? Or could the space have a potential fire where there are substantial amount of combustibles? That's generally, what's going through my head as I look over a set of floor plans and look to match occupancy hazard categories. MATCH AN NFPA 13 CATEGORY? Now, practically speaking, most of the time an area's gonna fall nicely within one of the categories that NFPA 13 gives us. We've talked about this. The annex portion of NFPA13 has all of those examples. There's plenty of examples of Light Hazard, Ordinary Hazard Group 1 and 2 and Extra Hazard Group 1 and 2. It's our space, whatever we're looking at within our building, it’s our space described in one of these. If we have a patient exam room that's part of a doctor's office, it's going to have an exam chair, some cabinetry, a sink, tile floors, acoustical ceiling tiles. Well, based on what's in that room, in this space, if a fire did occur, it would probably be similar to the intensity of say a single person office in a business building. That office might have a desk, some furniture, a table, cabinetry, a computer, carpet, acoustical ceiling tile. But between these two, we don't have combustible liquids. We don't have shielded hazards. We don't have stalls. We don't have tall storage stacks from the perspective of a fire, the fuel load, and the potential fire intensity are gonna be relatively similar. HAZARD CATEGORIES FOR EACH SPACE NFPA 13 would say the same thing. Here in the annex of NFPA 13 where these examples are listed, we specifically have hospitals listed as an example of light hazard. Is an outpatient doctor's office exam room a hospital? No, but the combustibles within the exam room are probably fairly similar to what would be in a hospital. Again, this is relatively speaking. What else is listed as an example for Light Hazard? Well, you got it, offices. So, in our first example, the exam room, or in our second example, that single person office, these both fall under Light Hazard. So, when I'm determining occupancy hazard classifications, I'm going area by area or space by space, sometimes room by room. And I'm doing my best to match the space with the appropriate hazard category. STORAGE Now when we come across storage – and this could maybe be listed as a “warehouse” or “storage room” or “rack area” or something like that, that’s a completely different approach. For storage, we first have to evaluate what is being stored, what is the commodity, how it’s being stored, like other shelves or racks or solid pile, and then we have to follow our code path in the storage chapters of NFPA 13 to get the guidance that ends up being a Design Criteria. Storage is treated differently than occupancy hazard classifications. We don't just see, oh, there's storage in this room. It's automatically Ordinary Hazard Group 2. What we need to do is evaluate what's going in that room, how is it going to be stored, follow our code path. We may end up in Ordinary Hazard Group 2 at the end of the day, but we have to go through the code path in order to get there. We'll cover this all separately and not in this segment today. I just wanna call attention to that. This is for non-storage. If we get storage, it's a completely different deal. GRAY AREAS What about spaces that are in gray areas? How do I know for sure that my space fits into one of these hazard classifications? Well, obviously not every building scenario is going to be listed in the annex of NFPA 13. There are roughly 75 different occupancy hazard classifications in the book, but there are unlimited amount of variations on how buildings are actually used and how fuel's actually stored. But what if I read through light hazard? And I'm not sure if my space fits there or not? Well, what I do is read ahead. Check the next higher classification and see if those examples better represent the space I have. Do those examples going from say, Light Hazard to Ordinary Hazard Group 1? Do the Ordinary Hazard Group 1 better match my space in terms of the amount of combustibles, the potential fire intensity that would happen in that kind of a room? For example, like is my doctor's office exam room, more like an auto showroom or a laundry facility, or a restaurant service area, a mechanical room, a glass or beverage manufacturing facility? No, I don’t think so. Those all are more intense from a fuel load and potential fire intensity perspective, so I feel good about classifying that doctor’s office exam room then as Light Hazard. CAN ONE BUILDING HAVE MULTIPLE CLASSIFICATIONS? Joe – you just read that hospitals are Light Hazard. Can one building have multiple occupancy hazard classifications? Yeah, absolutely. Different parts of a building will be used in different ways, they’ll have different fuel load. That hospital, just take a hospital for example. It will have exam rooms, it will have nurse stations, restrooms and corridors and visitor spaces. Those will have similar fuel loads and a potential fire intensity. They're all effectively are similar spaces. But that hospital will also have large mechanical rooms, it will have storage areas, electrical rooms, elevator machine rooms, maybe a parking garage. Those areas are all a higher hazard classification and they’ll be classified differently. So just because they're in the same building, we will have multiple hazard classifications. One building can and usually does have multiple occupancy hazard classifications. CAN ONE ROOM HAVE MULTIPLE CLASSIFICATIONS? Even one room can have and sometimes does have multiple occupancy hazard classifications. Take, for example, a large library. It will have stack areas with tall shelves of books, that's gonna burn relatively differently than open seating areas that are just there for reading. Those two spaces are gonna be classified differently. Now, all of this I say relatively – and I think that’s important – because we’re not looking at each individual piece of furniture or each cabinet – we’re trying to get more of a general sense of the hazard within the space. Now, if this is our first time doing it, that's gonna be difficult. We don't have any kind of intuitive feel for how a space is going to burn. There's no way that somebody that opens NFPA 13 for the first time is going to have that feel for how a space would burn at a fire. Fortunately, I've myself never seen a library stack room burn, or a lobby space or a reading space or anything like that. However, after repeated practice and repetition, we all get a much better feel and a more natural sense for how spaces fall within each of these classifications. ARE EXAMPLES ALWAYS A MATCH? So, Joe, based on the examples that are in NFPA 13, what you’re saying is that every museum or every club is gonna follow within Light Hazard? Well, no – and this is key – these examples are listed in the Annex of NFPA 13. They’re not a part of the enforceable part of the code. What is in the enforceable part of the code is the descriptions about the relative hazards. The annex examples are therefore guidance to the actual enforceable language that's in Chapter 4 of NFPA 13. So, is every museum or club always gonna be Light Hazard? Well, just take, for example, what if a museum space has an exhibition of caves like structures that’s built out of plastic bags? Well, that’s happened. That question just came up across my desk last week. These examples just taking museum and light hazard in the back of NFPA 13. Well, those are only guidelines meant to provide examples of the relative fuel load and fire intensity. They're not all inclusive, not all museum spaces are gonna be Light Hazard. If a club that's also listed as light hazard has a performing stage with curtains and pyrotechnics and combustible backdrops, that's no longer gonna be Light Hazard either. Even though it's still a club, there are examples intended to provide a general sense for how spaces would fall into a hazard classification. EVALUATING PLANS All right. So I go through the plans, look at floor plans and furniture plans and the descriptions of the spaces – I match those up with what NFPA 13 gives us. Got it. What if the description of a space is vague? What if I’m not sure how that space is actually going to be used? Well, this happens. Here, we need to ask the architect (who is the one responsible for being in contact with the owner) how this space is intended to be used, and what’s going in it. VAGUE DESCRIPTIONS A kids play area, just as an example, could mean a lot of different things. Is it like a childcare center or kids classroom? Is it an indoor play gym? Well, those are two totally different hazards, but they could both fall under the description of a kid's play area. Like many situations in fire protection, if we don't know, ask, ask what the intended use is, ask what's going in there, ask what kind of materials are gonna be used. All of that information can help us make a more informed decision and make a better engineering judgment. And that's circling back to the last video. Why many see this categorization as a responsibility that needs to end up under a professional engineer. In some (maybe even perhaps) many cases, there is gray area to be considered and it is an engineering judgment that incorporates the whole qualified ethically bound and being liable for that decision. That would be a professional engineer's responsibility. We're making an engineering judgment on what classification best matches our space. NO MATCHES? What happens if a space just doesn't fit nicely within one of those categories? Well, this is a gap again for sound engineering judgment. If we're the ones that are tasked with figuring out what that hazard classification needs to be, and it doesn't fall nicely into one of those silos, then as I see it, we fall into one of two categories. First, look for outside sources, interpretations, or other written guidance. The first and perhaps best place to look is for insurance guidance. Does somebody like Factory Mutual already address this in their data sheets? Have they already had their engineers take a look and evaluate how to best protect a space like the one we’re looking at? POSSIBLE FM GUIDANCE So, Factory Mutual has their guidance in what they call Data Sheets and those are free to access. You can go to the link below and see those (add arrow pointing down). (https://www.fmglobal.com/research-and-resources/fm-global-data-sheets) You may need a login, but it’s free and anyone can view them. FM Global Data Sheet 3-26 evaluates non-storage occupancies, and they provide guidance into what they call hazard categories. Again, we use an NFPA 13, we're using the term occupancy hazard classifications. FM global has their own criteria and they call those hazard categories such as hazard category 1, 2 or 3. Now FM global provides their own categories, their own design criteria for each of those categories. So, there's some deeper diving that needs to happen. If we're on an FM job, we can't just pluck, oh, hazard category 2 and then design everything else to NFPA 13. It gets more involved on the FM Global side when we're under an FM global job, I just wanna highlight that here. But if we're trying to see how a space should be treated and we don't feel like NFPA 13 is addressing our situation. That FM guidance is a great outside source to start with. Why start with FM global? Well, these are insurance recommendations based on loss history and their own engineering judgment, meaning they're protecting properties with the recommendations that they're giving here. They're not the building owner, but they're ensuring their clients. It's like saying, hey, I think my team's gonna win this weekend versus putting down a $10,000 bet on the game saying they're gonna win this weekend. Their money is where their mouth is, or they have skin in the game so to speak. FM, in particular, also has a tremendous history on serving the industry with a thorough understanding for fire protection. So, there's a whole lot more credibility here in other words than what my cousin did on a job last year. That's just my opinion. WHY FM NEXT? FM, because they are their own organization, also has the ability to adapt and adjust quicker than many of the committee-led consensus agreement organizations. If FM needs to address lithium-ion battery storage, because it's happening across their insured properties, well, they have the ability to put together an analysis and recommendations relatively quickly. This means they may offer guidance on new technology areas that NFPA 13 hasn't addressed yet. Not to go all out on FM, but because of their history and thoroughness, some other insurance organizations also will adopt and recommend the standards that FM global puts forth. So, it's not just FM properties that are affected by these recommendations. They're at least considered elsewhere, even with other insurers. There are also other insurer recommendations that exist like XL GAPS and some others. FM seems to be the easiest to access. Also, insurance recommendations will usually be a little more conservative than code-minimum. Meaning FM in some areas may recommend more than what code minimum requires. From an engineering standpoint, that's okay and sits well with me. If I find a gray area on my project and I'm looking for input on, and I lean a little conservative to make sure that space is adequately protected, well then, personally I feel like I’ve done my due diligence and honestly, I can rest a little bit easier at night. WHERE ELSE TO LOOK So, we go through this exercise, let’s say both NFPA 13 and FM Global both don’t clearly address my very unique situation. Where else can I look? My next stop would generally be a fire sprinkler organization to see if they've addressed it with informal expert opinions. Groups, like the NFSA (the National Fire Sprinkler Association) and AFSA (American Fire Sprinkler Association) both have groups of experts that dissect unique situations and make their own interpretations. Hazard classifications are a little bit harder to find, because like we've said before, this can fall into engineering judgment areas, but sometimes there's some really good input that's found from both of those teams. If they don't have something that was asked before that's already been published. Well, members of these organizations, they can write in their own questions and get some expert one-on-one help. And that can be an invaluable resource. But Joe, didn't you start a forum and there are others that have hits on Google? Why can't I just Google this? Well, forums are great for collaboration and they're great for sharing information. They can be a tremendous help to save time and give you a starting point to help move you in the right direction and make a responsible decision. But it's still your decision. You're still the one that has to own that decision. You can't go up on a stand after something happens and say, well, in 2008, I read an online post that solved this problem for me. It's a decision that's yours to own. Forums are great, like really fantastic for sharing ideas and they have and serve a very important role in my opinion. But at the end of the day, it's still your decision to own. SUMMARY So, all in all, what's the process for determining an occupancy hazard classification? Well, for me, I first look through the plans. I look for description of the spaces, furniture plans, floor plans, sometimes building sections, anything to give me a sense of what's going in that space and generally how it's gonna be used. Most of the hazard classifications are generally gonna fall nicely within one of the categories that NFPA 13 has given us. We match each different area with an appropriate hazard category. For storage, I set those aside and I need to evaluate those separately. So, I hold off on that for now. Most of the time, that's about it. If we don't have storage areas, that may be the entire job and we can move on. For areas in our building that are vague or don't fit nicely, I'll ask the architect or building owner how that space is intended to be used and what's going in so I can make a quality engineering judgment. If after getting the information I need, I still don't have a level of comfort with where that space is gonna fall, then I'll seek out FM global and see if they've addressed it. And if that's not the case, I'll look to national organizations to see if they've got published opinion pieces on it. And if not, I'll submit a question to them for some one-on-one outside input. Again, that's supplementing my own decision. It's my decision to make. I'm the one that's responsible for it, but I'm looking for reasons to validate what I'm thinking. At the end of the day, it's not just slapping a description on a space and moving on. I have to be the one to own my decisions and feel comfortable with what we're setting up so that the sprinkler system actually has a chance to suppress the fire. It's my decision made, my judgment that I need to feel comfortable with at the end of the day. That's my process for determining occupancy hazard classifications. And that's all for this one. I’m Joe Meyer, this is MeyerFire University.
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