If you know someone taking the PE Exam this week, it's time to give them a hug. Maybe not an actual hug; don't be a creeper, but maybe a kind supportive attaboy wouldn't be a bad idea.
Final Call for the PE Exam This Friday is the day for the 2019 Fire Protection PE Exam... the same exam that at least two hundred fire protection professionals have been honing in on the past few months. Changes Coming This year marks the last year of the written examination. Major changes are on the horizon for the Fire Protection PE in 2020, including question style, references, and going to a computer-based environment. The biggest change may be that no longer will any resource be allowed in the exam room. There'll be plenty to cover on the 2020 exam later on. Perhaps because of the big looming changes, we've seen a major uptick around here in the interest in the Fire Protection PE Exam. I would guess that this year will set the record for the number of examinees. That's a great thing. I'm thrilled that the fire protection industry as a whole is growing, and I hear almost weekly about how rare Fire Protection Engineers are in our industry. What is the PE Exam? For those who don't know, the PE Exam is the Principles and Practice of Engineering examination which is administered by the National Council of Examiners for Engineering and Surveying (NCEES). The exam is the major milestone to getting a license to practice as a Professional Engineer in the United States. In order to take the PE Exam, examinees must typically first complete a four-year ABET accredited engineering program and a Fundamentals of Engineering (FE) Exam as well as accruing four years of experience working with a licensed engineer. Of course the requirements vary by state but that is the most common requirement. Last Minute Exam Advice If you have a copy of the Prep Guide you already know there's quite a bit of detail on exam advice passed down through the years included in the book. Regardless of how many hours you've spent studying (whether two or two hundred), there will always be topics that are over-emphasized, poorly worded questions, and niche questions that seem to have no basis in any reference materials. Keep calm and exam on! Skip and come back to questions later. Some of these questions are just on trial for future exams and others will get disputed and thrown out. All you can do is your best. Don't worry about surprises you can't control but focus on what you know and give it your best effort. Best of luck, you've got this! Updates for 2020 PE Exam If you have sent in information on the 2019 Edition for suggestions or potential updates, thank you! With all that's happened around here this summer I haven't been as responsive to PE Exam emails as I've tried to be in the past. Please know that I go through all of these and make updates for future examinees, and I greatly appreciate your time in sending suggestions in. New Feature on Quick-Response Remote Area Reduction I've had a pet peeve about one of my own tools. Awhile back I created a calculator that will determine the allowable reduction in the hydraulically remote area based on the use of quick response sprinklers. It's a quick-hitter and one I use often. Each time I use it, though, I still end up using the reduced area and punching in 1.2 times the square root of the new area in order to lay out my hydraulically remote area. Being that I'm all about convenience (ie: laziness) and efficiency, I've now added that basic calculation in the tool as well. You can see the new feature here. If you have similar nuances on how these tools can be improved, let me know! I'm always happy to entertain new ideas. You can always reach me at [email protected]. Have a great week! I'll come out and say it. I’m a millennial. I like to think I can opt out of millennial status voluntarily, but I'm told it doesn't work like that. Technicalities… I like to think that the relentless pursuit of finding better & faster ways to do better work is about innovation and constant improvement. I guess it could also just be considered finding ways to avoid work or wanting the "apps" to do any real engineering. Today's post covers one of my favorite cheats on checking site elevations and distances. It's super easy and a major benefit when setting up or reviewing hydraulic calculations. On a side note I'm also told that the kids these days call these "hacks". I'm told that a "hack" is a good thing, so I'll roll with it. Besides - age is just a state of mind, right? I'm cool, I promise. Just don't ask my kids. Here's the “hack” - just follow these steps: Get Elevations Between Any Two Points 1. Open Google Maps (https://www.google.com/maps) 2. Enter or zoom in on any address. 3. Right click on any location you wish to get an elevation on. Select "Directions to here" 4. Now right click on any location at least a block away, such as your tap for the building's water connection. Select "Directions from here" 5. Now you'll have opened up the directions dialogue. Instead of car directions, click on the walker icon in white at the top. 6. Click on the very bottom description in gray. It often reads “Mostly Flat”. This opens up an elevation view from your original point (such as your building’s water tap) to your building. This shows your end elevation (against sea level), your original elevation, and the elevation difference between the two. Measuring Site Distances While still in google maps, you can also get distances on a site.
Here's a video showing both (click this link if you don't see the video): So What? Earlier this year I had a project I was reviewing which showed no elevation difference between the flow test and the base of the project. The pipe distance was roughly accounted for, but no elevation. I checked the test distance on Google Maps and despite only being several hundred feed from the project, the test was at an elevation 32 feet lower than the base of the project. Did this affect the hydraulic calculations? It absolutely did. The calculations went from having 6 psi safety to being 8 psi over the available water supply. The measurement tool comes in handy for many projects where site plans are not prepared. This doesn't come up quite as much in new construction, but certainly for retrofits or projects with no site work - a site plan often isn't available. Use of quick measurements can give some guidance towards using conservative measurements for hydraulic calculations. If you already knew these two tricks, congratulations, you’re probably also a millennial. If you didn’t, and would like to send money for the gobs and gobs of time these simple tools will save you in the future, please make the check out to “Joe’s Beer Fund.” Actually better yet – just tell another friend about this site. It is always very much appreciated! Hope you have a great rest of your week. Last week I discussed a common question in residential construction concerning whether NFPA 13R could be used, or whether NFPA 13 had to be used. If you haven't read it, you might check it out. Here's a link. The four global limitations to using NFPA 13R include:
The last qualifier is often the most difficult to assess, and is an important question that the architect or code consultant for the building will need to answer. To help determine whether a building can use NFPA 13R, here's a PDF cheatsheet that shows differences in code allowances using NFPA 13, 13R, 13D, and no protection at all. All of the references are to the International Building Code 2018 Edition, but this should help offer some quick guidance on different code allowances to check for your project. As always, it's worth using this as a starting point and then exploring the code nuances to be sure your project is up to snuff. If you haven't already subscribed - you can do so here. This blog is all about promoting best practices in fire protection by providing tools, resources, and helpful articles. Other Notes Travis Mack at AFSA If you're going to AFSA's Conference in San Diego next week, be sure to check out Travis Mack's presentation on this topic. He's an industry leader & expert in everything suppression. Correction on the Porte-Cochere Logic A couple weeks ago I discussed the differences between different forms of heat transfer in the context of flame spread. I made a point that conductive heat transfer is the least critical of the three forms of heat transfer, but suggested that fires "jump" across roadways due only to radiation heat transfer. This is due primarily to convective heat transfer - strong winds can promote fire growth far faster than radiative heat transfer can - and it often does for large wildfires. Prep Guide I mentioned last week - but I'm down to about a dozen copies of the 2019 PE Prep Guide Edition left for the year. If you know someone who is looking for a copy you might suggest they get it sooner rather than later. Thanks & have a great week! For the contractor clients I work with I regularly look over jobs pre-bid. I’ll review drawings, read specifications, and compile all my notes looking for red flags that could impact the job from a design standpoint. (The cheatsheets that I use to breakdown a job is now all in the Toolkit) Last month I reviewed an apartment complex job for a bid where the code summary had conflicts. The IBC Chapter 5 summary indicated and NFPA 13 system while the IBC Chapter 9 indicated an NFPA 13R system. There were no other references to a fire sprinkler system in the rest of the documents or specifications. These are the projects that I blame my hair loss on. It's another bad example of project documentation. Regardless, the question of NFPA 13 versus NFPA 13R is something that comes up regularly and is the topic of this and next week's article. Why Does it Matter? NFPA 13R is not built with the same intent as an NFPA 13 system. NFPA 13R systems are designed to “prevent flashover (total involvement) in the room of fire origin”. By doing so, they intend to improve the ability for occupants to survive a fire by evacuation. 13R design is primarily concerned with protecting areas of residential buildings where fires cause loss of life. It is not as concerned with fires in areas where fatal fires in residential occupancies do not originate. (Reference IBC 903.3.1.2 Annex) NFPA 13 systems, however, intend to provide a “reasonable degree of protection for life and property”. In a general sense, NFPA 13 systems are concerned with both life safety and property protection. The goal is to suppress a fire near its' point of origin, regardless of the level of risk to life safety. Cost can be largely impacted by the NFPA 13 vs. NFPA 13R decision - especially in wood construction buildings with attic spaces and overhangs. Cost Impact Aside from having different purposes, NFPA 13 vs. 13R decisions can have major implications on system cost. NPFA 13R systems allow sprinkler omission in a handful of areas which 13 does not. These include small closets, exterior balcony closets, concealed spaces, elevator machine rooms, garages, carports, attached porches, and attic spaces. I've summarized these with a cheatsheet here. For wood-construction (a mainstay in residential design), attic sprinkler systems under NFPA 13 can command a major cost premium. These attic systems need dry valves, air compressors, use of steel in lieu of CPVC, special application sprinklers, and design requirements that can require large diameter pipe. Testing and maintenance is also a long-term ownership concern. Not only do dry attic systems require regular low-point drainage, but they often corrode faster than wet systems . Attic systems are one area of a building that can be a huge difference between NFPA 13 and 13R. That said, I’ve also worked on projects where 13R has little to no impact on the project price. A flat-roof building built with non-combustible structure, for instance, offers no major difference. The only impact was the lower density permitted for residential-style sprinklers. Using the 0.05 gpm/sqft in lieu of 0.10 gpm/sqft of NFPA 13 resulted in smaller pipe diameters for an NFPA 13R system. Buildings must be residential, four stories or less, 60 feet in height or less, and not use any code exemptions for an NFPA 13 system in order to use NFPA 13R.
When Can I Use NFPA 13R? There are four global limitations where an NFPA 13R system can be used. These include:
"My project is design/build with deferred submittals. Can’t the contractor determine this?" No - and I can’t stress this enough – please do not leave this determination to a contractor. It doesn’t matter if you’re an architect, mechanical engineer, or the expert code consultant. There are a number of code exceptions that can only practically be determined by the design team. The sprinkler contractor is an expert on suppression – not on architectural design decisions and the code paths for those decisions. What are the building code exemptions that require an NFPA 13 system? The code exceptions show up for building height increases, building area increases, egress widths, travel distance limitations, occupancy separations, corridor wall ratings, hazardous material increases, inclusion of atriums, unlimited area buildings, allowable area of openings, vertical separation of openings, draftstopping, interior finishes, floor finishes, manual fire alarm systems, and several others. Sounds like a lot? It is. Fortunately I’ve got a cheatsheet coming next week where I’ll explore these differences in more detail. If you’re interested in getting a copy, subscribe here and it’ll be emailed directly to you. Other Thoughts A couple weeks I posted a link on this month’s sponsor Engineered Corrosion Solution’s whitepapers. Many of you have already checked it out, but if you haven't there's a MeyerFire welcome page here: https://www.ecscorrosion.com/meyerfire-welcome I had a couple people ask about the whitepapers, so here’s a direct link to them. Specifically, be sure to check out "Industry Myths Regarding Corrosion in Fire Sprinkler Systems" and "Six Reasons Why Galvanized Steel Piping Should NOT be used in Dry and Preaction Fire Sprinkler Systems." PE Prep Guide 2019 Selling Out There's been a ton of interest this year in the PE Prep Guide. I genuinely appreciate every single person who's checked out the book for this year's exam - there has been more interest than ever before and I suspect the exam turnout could be the most ever for the Fire Protection P.E. Exam. Next year's exam in 2020 will go computer-based and have major changes, so the PE Prep Guide will undergo big changes as well. This year's shipment of the 2019 Edition is just about out, and because of the big changes next year I won't be ordering extra copies. We currently have 16 copies available, so the 2019 edition will likely sell out by October's PE Exam. If you'd like to get a copy of the 2019 PE Prep Guide, please consider doing so now. After the 2019 Edition sells out we'll still have 2018 PE Prep Guides available, and I'll ship an errata list with it. Any questions, please reach out to me at [email protected]. Last week I discussed across a common misconception with porte-cochere sprinkler requirements and how code addresses sprinkler protection for these structures. This week I’m diving a little deeper with some estimates of how a porte-cochere fire would actually affect a main building, based on distance from the building. It’s important to note that this exercise is largely academic: with the calculations below I’m making some gross assumptions that overly simplify the situation. This has not been vetted with Ph.D. experts nor gone through full scale fire testing. I’m just running some basic numbers with big assumptions to illustrate a point. Heat Transfer From what science gives us - heat is transferred by three methods. Conduction, convection, and radiation. Conduction is the transfer of heat by objects touching each other. The direction of transfer is dictated by hot-to-cooler materials in direct contact. Convection is the transfer of heat caused by the movement of gas (or a fluid). The direction of transfer is largely dictated by overall movement of the fluid, and for smoke tends to be vertical. Radiation is the transfer of heat from the emission of electromagnetic waves. The direction of transfer is in all directions, but can reflect and re-emit from other surfaces. Heat Transfer for a Flame For a flame, depending on the fuel, most of the heat will be transferred away from the flame source primarily by convection. The chemical reaction (oxidation) of a flame will cause gases to heat. The heated gas’ molecules will become more active and less dense. With less-dense gas than surrounding cooler air, the warm gas will rise up and away from the flame source and carry solid particles forming hot smoke. Radiation will typically comprise 20-35% of the overall heat release rate for a fire. Radiation transfers heat from the source in all available directions until it contacts another surface. Once in contact with other surfaces, radiation can be absorbed or re-emitted from the surface, depending on the surface material. Conduction is the least important mode of heat transfer in an open fire. Radiation near a flame’s origin, for example, often emits and heats up adjacent surfaces with more impact than conduction. For wall assemblies, conduction of heat through penetrations becomes important, but for flames in open environments conduction plays only a small role. Three Porte Cochere Scenarios 100-foot Separation Now imagine a porte-cochere that is 100 feet (30 m) from the face of a larger main building to the center of the porte-cochere. If the porte-cochere is completely inflamed, how would it transfer heat to the main building? It would transfer heat only by radiation; and in very small amounts. Assumptions include a 5 megawatt (MW) fire from a wood-built porte-cochere, a 100-foot (30 m) center distance from the main building, an atmospheric transmissivity of 0.95, and a 30% of the overall heat loss as radiation. Using the Lawson and Quintiere Point-Source Method, the incident radiant flux (a measure of the heat energy per area) is 0.13 kW/sqm. This radiant flux is about 10% of the flux for a 1st degree burn on unprotected skin. 30-foot Separation Now move the porte-cochere to be 30 feet from the face of the building. Radiation will again transfer heat to the face of the building, but in a much larger amount. Because radiant flux is related to the inverse square of the distance between the targets, this 30-foot distance will actually have a radiant heat flux 10 times greater than a porte-cochere fire 100 feet away. For the same size fire as before but at 30-feet, this could be about enough heat for a 1st degree burn. At the 30-foot distance, however, heat transfer to the main building is still primarily by radiation. The hot, buoyant smoke is still primarily driven upward from the porte-cochere and would likely not reach the main building unless strong winds directed the hot gases. 10-foot Separation Now imagine this same porte-cochere, but this time centered only 10 feet (3 m) from the main building. Radiation heat transfer is now 10 times greater than the 30-foot distance, and 100 times greater than the 100-foot distance. At only 10 feet from a 5 MW fire, the heat flux is enough easily cause 2nd degree burns for unprotected skin. Additionally, this heat flux is now approaching the critical heat flux for ignition of some building materials. The critical heat flux is the minimum amount of heat, per area, required to cause ignition. There's several factors that contribute to ignition including exposure time, material thermal properties, surface temperatures, and the actual heat flux versus critical heat flux - but for our purposes I'm only showing this critical heat flux for a couple siding materials. Wood, for instance, has been tested to have a critical heat flux of approximately 10 kW/sqm. Vinyl siding has a critical heat flux of approximately 15 kW/sqm (both values from SFPE Handbook of Fire Protection Engineering, Table A.35, 5th Volume). When we look at the heat flux already produced by a fire of this size at 10 feet we can see that we're already approaching the critical heat flux for both wood and vinyl. Actual Separation
Now let's speak in practicality. Porte-cocheres are built to allow visitors to enter and leave cars without exposure to rain or sun. Is a 30-foot or 100-foot separated porte-cochere provide any value to a building? No, of course not. This exercise just shows that with reasonable assumptions, a 10-foot physical separation assuming a 5 MW fire begins to approach the critical flux needed to ignite a nearby building. Fire Size Would the actual fire be 5 MW? It's difficult to predict and will vary widely by the materials used and the shape it conforms. A point-source approximation is a large oversimplification given that a wooden canopy would burn in a very different configuration than a condensed pile of wood pallets, for instance. Convection What about convection? Up to now we've still only discussed heat transfer by radiation. If a porte-cochere is close enough to a building, convective heat transfer from the hot smoke will begin to contact the main building and heat surfaces along the face of the main building. This could also be aided by wind conditions as well. As I explored a little last week, a porte-cochere that is only separated inches or a couple feet from a building is hardly any different than a porte-cochere that's attached to the building. That's largely because of convective and radiative heat transfer. The further away the porte-cochere is, the less convective heat transfer plays a role and the lower amount of radiative heat will be transferred. Fire-Resistive Construction What if we create a firewall or fire barrier? Both would slow the spread of fire and help prevent the main building from burning. The International Building Code relaxes the physical separation with fire-resistive construction, and for good reason. Heat flux becomes much less important when the exterior is of non-combustible construction. Summary It can be easy to get lost in code minutiae and live by the black and white lines of what code reads. I find that it's important to remind myself about context about each building and where good engineering judgement plays a role in protecting buildings from fire. This overly-simplified series of calculations just shows the tiers of radiative heat transfer and how much it is affected by the separation distance. The further away a building is from another, the less convective heat transfer plays a role (if any) and the less radiative heat transfer occurs. If you found this interesting, let me know by leaving a comment here. Always happy to hear other opinions. If you don't already follow the weekly blog, consider subscribing here. Thanks for reading!
In February of last year I put together a flowchart that covered sprinkler requirements for exterior projections. If I had a Top-10 Articles list, it'd be on it.
If you haven’t read it,here’s a link to the original article. Porte-Cochere Updates Since I wrote this article and posted the original flowchart, I’ve received some encouraging feedback and thoughtful comments. I’ve updated the flow chart this week to address specifically sprinkler protection of porte-cocheres: What's a Porte-Cochere? First, because I have no idea where the term “porte-cochere” originated, I’m talking about the covered entrance where vehicles can pass through as part of an entranceway to a building. Not to point fingers, but I’m guessing the term “porte-cochere” was dreamed up by an architect to disguise the fact that they’re sticking a carport on the front of their building. Maybe it’s my Missouri roots, but what we’re talking about here are just fancy carports that can be driven through. Now stepping down from the soapbox… "If It's Not Touching the Building..." Stop me if you've heard this one before. One common assumption I’ve heard repeatedly from architects and contractors concerning porte-cocheres is that sprinkler protection isn’t required for porte-cocheres if they are not connected to the main building. Unfortunately, that's not justified by code. It is true that porte-cocheres, on their own, often do not require fire sprinkler protection. They will generally fall under a Type U (Utility and Miscellaneous Group) Occupancy, which do not require fire sprinklers by IBC 903.2. However, in order to qualify as a separate “building”, the International Building Code requires a physical space separation, a fire-rated separation, or a combination of both. In terms of a porte-cochere attached to a main building, the porte-cochere would be considered a separate building by any one of the following:
As an example, if the main building is a Type V-B (combustible construction), Residential R-2 Occupancy (such as a Senior Living facility with more than 16 people), then the minimum requirements for a porte-cochere as a separate building would be:
Applying Logic From a practical standpoint, what is the difference between a porte-cochere that’s six inches from the main building and one that is touching the main building? None. Zero difference. I’ll explore this from a scientific perspective in next week’s article, but in short - conduction heat transfer makes little difference in the spread of fire from one structure to another. Want to know why forest fires can “jump” across highways? It’s not because trees are locking branches above roadways – it’s because of radiative heat transfer. So why do we get so tied to the concept that if the porte-cochere isn’t touching the main building that it’s as if it doesn’t exit? I’m not sure exactly, but it seems to come up quite frequently. One Note on Concealed Spaces NFPA 13 has two separate sections that affect porte-cocheres. The first is protection below overhangs, canopies, & porte-cocheres. This article and the flowchart address this situation. The second section is protection within concealed spaces. If your porte-cochere does not require sprinkler protection per the building code, then no sprinklers are required regardless. If that's not the case, and your porte-cochere has concealed spaces within it, check out NFPA 13's Special Situations section to see if the concealed spaces require sprinkler protection. These may still be required to be protected even when sprinklers can be omitted below the ceiling. This show ups in Section 8.14.1 of the 2002 Edition, Section 8.15.1 in the 2007-2016 Editions, and Section 9.3.18 in the 2019 Edition. Losing the Forest for the Trees I sometimes find that when assessing code it is easy to lose the forest for the trees. Sometimes I can be so fixated on finding one specific answer that it is easy to step back and assess the ‘big picture’. Addressing overhangs and canopies can get that way. While I don’t always get the opportunity to address fire protection intent with a building owner, I have to keep in mind that code only prescribes the minimum requirements. We can always elect to improve fire protection & life safety above code minimum. Two recent local fires come to mind when looking at how sprinkler protection affects overhangs and how different owners were impacted very differently. The first fire occurred at an apartment complex when a tenant left a lit cigarette on the third story balcony of an apartment complex. The cigarette started a fire on the unprotected balcony, which spread into the apartment attic (without draftstops) and quickly spread across the attic of the entire building. The upper two levels were badly damaged along with the entire attic and roof needing replacement. Another fire occurred, more recently, at a three-story office with a porte-cochere. A car fire underneath the porte-cochere activated a single sprinkler which suppressed growth until the fire department arrived. The porte-cochere had smoke damage, but the fire had no impact to the main building. No downtime, no multi-million dollar rebuild. From the photos it was difficult to see any impact from just inside the main entrance. These are two different situations of course; the first likely an NFPA 13R and the second an NFPA 13 system. Nonetheless it raises the issue of making sure that we, as professionals, inform and have dialogue with the building owner to not just determine what code minimums require, but what levels of protection may serve them best. This Month's Sponsor I'd like to introduce this month's MeyerFire sponsor with Engineered Corrosion Solutions. They are experts in the corrosion space for fire sprinkler systems and have a long list of helpful resources on their website. As a side note, some of their original whitepapers and case studies were instrumental for me in my understanding of current corrosion challenges. When should we specify galvanized pipe? Is MIC or oxygen-induced corrosion a bigger concern? What can we do to stop corrosion entirely? They have it all here. Thanks to the ECS team for helping promote this site and supporting my efforts to develop new resources for the industry. Next Week Next week I'll explore the concept of porte-cochere separation distance, but from a modeling perspective. How much does the distance impact radiative heat transfer? How does convective heat transfer play a role? I'll explore this in more detail and from a calculated perspective next week. If you don’t already get these weekly articles via email, subscribe here. If you know someone who might be interested, please pass a link along. Thanks and have a great week! There’s no real way around it: I love cheatsheets. In a design course in college we received 5x7 index cards to include any handwritten notes we wanted for an upcoming final. I wrote so much on that card with handwriting that was effectively size-4 font that it could have been displayed as a work of art. Nearly an entire semester summarized to a 5x7 card. It was a thing of beauty. While I no longer have a need to write so small, I still enjoy having information organized so that it is extremely easy to access. If you haven’t seen these before, here are a couple cheatsheets I’ve created so far: Summary of Differences of NFPA 13, 13R, and 13D Sprinklers & Passive Fire Protection Options
Last week I covered important considerations surrounding fire department connections from a design perspective, which was a joint-effort with QRFS covering the topic. At some point I’ll compile the best blog posts and resources into a hardcover reference book. For this week, however, here’s a cheatsheet on requirements surrounding fire department connections across NFPA 13R, NFPA 13, and NFPA 14:
Why are fire department connections (FDCs) so important to a suppression system? They are the link between initial response and supplemental help. Despite appearances, sprinkler systems are not intended to discharge forever. Their goal is to suppress long-enough that firefighters can take over and finish the job. Standpipe systems exist to extend the reach of the fire department in tall, wide or complex buildings. Manual standpipes depend upon pressure and flow from the fire department. What single piece of equipment is relied upon to make the transfer? The FDC. This week's article is an overview of fire department connections from an engineer’s perspective. It is one part of a two-part series covering fire department connections. Read more from a supplier’s perspective at Quick Response Fire Supply here. Authority Intervention Needed Fire department connections are a unique piece of a suppression system in that they’re not just governed by the designer and code. NFPA 13 and 14 require that fire department connection type and location is coordinated with the Authority Having Jurisdiction. Early in design, prior to bid, I’ll call the local fire marshal and coordinate each of the following big-picture elements: Coordination Item 1: Type of Fire Department Connection The most popular types of FDCs? Siamese (2 x 2-1/2" threaded connection) and Storz (4" or 5" with or without 30-degree elbow). In my very unscientific study of jurisdictions I call (nearly half are local to my area), I've found the following; 73% use Siamese-type 2-1/2” fire department connections, 11% use 4” Storz connections, and the remaining 16% use 5” Storz connections. Of these, 13% have special requirements such as Knox Locking caps, 30-degree elbows, or irregular threading. There’s no right or wrong answer here – I just want to be sure what I’m calling for or showing on plans match what the jurisdiction uses. Large diameter Storz-type fire department connections have become more common for their ability to quick-connect a single hose and flow large amounts of water. Coordination Item 2: Location of Fire Department Connection The most obvious coordination during design is the location of the fire department connection. My design preference, driven by installation effort and cost, is typically in the following order: 1. Wall-mounted FDC, adjacent to the sprinkler riser 2. Wall-mounted FDC, remote from the riser (such as the front of the building) 3. Freestanding FDC, downstream of a site backflow pit or hotbox 4. Freestanding FDC, connected underground into the sprinkler riser room The first couple options are not always workable and depend on the building. Sometimes the water supply and riser room are in the back of a building inaccessible to the fire department. This would be a bad place for an FDC. Sometimes the front face of a building is "grand view" with large glazed curtain walls and no room to mount a fire department connection. This comes up with large offices or modern schools. Sometimes a building-mounted FDC doesn’t make sense with major hazards; why risk firefighter safety in these cases? High-rises, for instance, require multiple FDCs due to the potential for falling glass that could injure firefighters or sever hoses. If there's potential for wall-collapse (think high-hazard warehouse wall) then a wall-mounted FDC also may not make sense. Freestanding FDCs can make a lot of sense for projects like these. Considering most of my work is two stories or less and light commercial, it may not be surprising that roughly 85% of projects include building-mounted FDCs. The remaining 15% have necessitated freestanding FDCs. Some jurisdictions require freestanding fire department connections, but it typically depends on the type of building and hazard presented. Coordination Item 3: Distance of FDC to Nearest Hydrant As a designer it would be great if I could operate in the dark. Send me all the information I need to do a design, I do it, and everyone’s happy. If it were that simple, though, we’d probably already have machines design and do it without downing two bags of Doritos and a half hour of facebook each day. Back to the topic: FDC-to-hydrant distance has an impact on the tactical approach in firefighting. Many designers & installers in our field are current or former firefighters. They could readily speak to this. I’m not one of them, but I can imagine that having to shut down a major roadway or cross a parking lot with hundreds of feet of hose quickly during an emergency is not exactly the easiest thing to accomplish. As a result I like to ask AHJs what distance the FDC should be to the nearest hydrant. Of my highly unscientific and locally-biases results, 41% of jurisdictions require a hydrant to be within 100 feet of the FDC or less, 47% require a hydrant to be within 150 feet, and only 16% of jurisdictions require a hydrant within 200 feet or more of the FDC. These three elements are a part of my code calls. Next week I'll distribute my FDC Cheatsheet that outlines requirements for FDCs across NFPA 13, 13R and NFPA 14. If you haven't already subscribed, consider doing so here. What do you look to coordinate with the AHJ? Discuss your experience here. Want more coverage on fire department connections? See the other half of our two-part series on fire department connections here: Quick Response Fire Supply. One project question I very commonly receive from civil engineers is whether a post-indicator valve (PIV) is required. In short, there are options. I'm exploring PIVs in more detail in this week's article. If you want to get more like this, subscribe for free here. Purpose of Post-Indicator Valves Post-indicator valves have long been used to stop the flow of water into a building during developed stages of a fire. Exterior wall collapse of a burning building poses a threat to break water supply mains as well as create many openings to the water supply. Without a valve to stop supply to these areas, firefighters and their efforts could be compromised by the loss of pressure and outflow of water to areas of a site that don't need water. With the recognized effectiveness of sprinkler systems and cost pressures, the requirement for post-indicating valves have become more relaxed in the last decade. Code references to account for building collapse, for instance, now appear only indirectly in location requirements for hydrants and post-indicator valves to be sufficiently away from a building. Components of Post-Indicator Valves The post-indicator valve has several important features - first is the ability to quickly shut the valve with use of the post indicator valve handle. The second is to quickly see whether the system is in the 'open' or 'shut' condition in a protected enclosure. It can sometimes be difficult to see after years of dirt on the glass, but not impossible. The valve itself is along the water main below frost depth such that only the stem is subject to freezing conditions. It's a simple concept that's carefully crafted to protect the valve and stem in a reliable fashion. One example of a post-indicating valve - a Mueller Company Vertical Adjustable Post Indicator Valve (see https://www.muellercompany.com/fire-protection/ulfm-indicator-posts/) History of the PIV Requirement So is a post-indicator valve required or not? This used to be an easier question to answer. While not a referenced standard from the International Building Code, the International Fire Code requires that all private fire service mains be installed in accordance with NFPA 24 (IFC 2000-06 Section 508.2.1, 2009-18 507.2.1). NFPA 24, the Standard for the Installation of Private Fire Service Mains and Their Appurtenances, governs system requirements between a water supply main and a building's service entry. Up until the 2010 Edition, NFPA 24 required a listed post indicator valve on every connection from a private fire service main to a building unless special criteria were met (NFPA 24 Section 6.3). The special criteria included the use of a non-indicating underground gate valve with a roadway box and T-wrench or locating an inciating valve in a pit. Either special case required approval of the AHJ. Current Valve Options within NFPA 24 Since the 2010 Edition, NFPA 24 gives a series of options for isolating a building's system and does not mandate that a post-indicator valve be used. These options (from 2010-13 6.2.11, 2016-19 6.2.9) include:
While still considered an "indicating" type valve, wall indicating valves are generally less preferred than post-indicating valves as they are more susceptible to a building collapse than post-indicating valves. Post-Indicator Requirements of NFPA 14 NFPA 14, the Standard for the Installation of Standpipe and Hose Systems, also weighs in on post-indicator valve requirements. NFPA 14 requires that each water supply (except for an FDC) shall be provided with a listed indicating valve in an approved location (NFPA 14 2000 4-2.6.1, 2003-07 6.2.6.1, 2010-19 6.3.6.1.1). The prescriptive way to accomplish this is through the use of a post-indicating valve. Annex material within NFPA 14 goes further, stating a list of preferences for outside control valves:
NFPA 14 does give exceptions (as is almost always the case in fire protection), but they require AHJ-approval. Wall-point-indicating valves, or underground valve with roadway box and T-wrench, are alternative options that require AHJ approval (NFPA 14 2000 4-2.6, 2003-07 6.2.6, 2010-19 6.3.6). Post-Indicator Requirements of NFPA 13 So where does NPFA 13 stand on post-indicator valves? In short, it doesn't. NFPA 13 only states that where post-indicator valves are used, the top of the post must be 32-40 inches above grade, and they must be protected against mechanical damage (NFPA 13 2002 8.15.1.3, 2007-16 8.16.1.3, 2019 16.9.9). AHJ & Insurer Inputs Authorities Having Jurisdiction may also want to weigh in on requirements for post-indicating valves. Some municipalities write code amendments to require PIVs, while others may request PIVs be installed for certain building types. Insurers, such as FM Global, may also want input. FM Global for instance, recommends that each system has a control valve a minimum of 40 feet from the building (with less preferred options also recommended in Data Sheet 2-0 2.6.2). Best Practice What's the best course of action for your project? First, check for local or state code amendments that may affect post-indicating valves. If you have a standpipe system within the building, plan to provide a PIV. Last, check with your AHJ for any nuanced requirements you may be missing or to coordinate a location with the AHJ. Want More? Not already getting these free weekly articles? Subscribe here. Found this helpful? Share on LinkedIn.com or send to a friend. MeyerFire is all about helping you do great work in fire protection with tools, tips and resources. It is a popular and well-established concept that water and electricity don’t mix. Water is electrically conductive which creates a major hazard of electrocution where a continuous pool of water meets a live electrical feed. Can We Omit Sprinklers in Electrical Rooms? On a few occasions I have come across building authorities and building owners who assume that sprinklers will not be installed inside traditional electrical rooms. Why? The basic tenant that water and electricity don’t mix. While the concept is important, the intent of sprinkler protection throughout a building is not just for each item within a building, but the building itself. The primary intent of sprinklers is suppression – or stated differently – to prevent the growth of fire from the room of origin throughout a building. This includes all the rooms and spaces beyond just the electrical room where a fire could begin. This week I’m digging into guidance surrounding electrical rooms. NFPA 13 Guidance
NFPA 13 (2002 Section 8.14.10.3, 2007-10 8.15.10.3, 2013 8.15.11.3, 2016 8.15.11.2, 2019 9.2.6) allows sprinklers to be omitted in electrical rooms, but only where each of the following are met:
Concerns with Providing Sprinklers in Electrical Rooms Providing sprinklers within electrical rooms could:
Historical Approach Prior to the 1994 edition of NFPA 13, important electrical equipment were required to have hoods (or shields) comprised of non-combustible construction to prevent direct contact by sprinkler discharge. All electrical rooms were required to be sprinkler protected. Beginning with the 1994 edition, NFPA 13 introduced language to address concerns for firefighter safety and equipment damage. Sprinklers could be omitted in electrical rooms where the room contains dry-type equipment (no oils), is dedicated to electrical equipment only, is fire-resistant to reduce fire spread, and the room has no storage hazard. The 2016 Edition, the requirement for equipment hoods or shields was removed to direct it under the scope of NFPA 70. Just recently for the 2019 Edition new text was introduced such that no storage is permitted (non-combustible storage had been allowed) and liquid-type K-class (less flammable, non-spreading fluids) would be allowed. International Building Code Input The International Building Code (IBC) does not allow the omission of sprinklers “merely because it is damp, of fire-resistance-rated construction, or contains electrical equipment” (IBC 2000-18 9.3.1.1.1). Within the same code section, the IBC does allow sprinklers to be omitted in “generator and transformer rooms separated from the remainder of the building by walls and floor/ceiling or roof/ceiling assemblies having a fire-resistance rating of not less than 2 hours.” These rooms must have an approved automatic fire detection system. According to IBC commentary, buildings with sprinklers omitted in one of the sections allowed by the IBC would still be considered fully-sprinklered throughout and in compliance with the code and NFPA 13. This distinction is important as it carries eligibility for code alternatives, exceptions and reductions. Today’s Consensus Combined, both the IBC and NFPA 13 require electrical rooms to be protected unless the prescriptive alternative option is followed. As NFPA 13 commentary outlines, sprinkler systems have been successfully installed in rooms containing electrical equipment for over 100 years with no documented instances of a problem. While still seemingly controversial, most projects designed today include sprinkler-protected electrical rooms. Get More If you enjoy these articles, subscribe here. If you're already a subscriber, consider forwarding to a colleague. MeyerFire is all about dissecting real challenges that real people face in fire protection design. I'm thrilled you're a part of our journey for better fire protection worldwide. |
ALL-ACCESSSUBSCRIBEGet Free Articles via Email:
+ Get calculators, tools, resources and articles
+ Get our PDF Flowchart for Canopy & Overhang Requirements instantly + No spam
+ Unsubscribe anytime AUTHORJoe Meyer, PE, is a Fire Protection Engineer out of St. Louis, Missouri who writes & develops resources for Fire Protection Professionals. See bio here: About FILTERS
All
ARCHIVES
July 2024
|