First - last week I put together a draft PDF cheatsheet for fire alarm design in elevators. Lots of great response to that tool. One major flub on my part - I didn't actually link to it. Here's an actual working hyperlink (fingers crossed).
K-Factor & Pressure Versus Area & Density
One of the hand calculations I do frequently when laying out sprinkler systems is comparing the k-factor, minimum pressures, and resulting flow for the sprinkler. It comes up all the time with residential-style, extended coverage, special application, and storage sprinklers.
Many hydraulic calculation programs do this comparison automatically. That being said, it is important to understand and compare the minimum flow from sprinklers for a hydraulic calculation.
Reducing unnecessary flow from a sprinkler reduces the total calculated flow from a system, which has major impacts on pipe sizing for some branch lines, cross mains, feed mains, and even the underground service size.
Driver #1: K-Factor and Minimum Pressure
There are two drivers for the actual minimum flow that must come from a fire sprinkler.
The first driver is the K-Factor and Minimum Pressure. This equation is
Q = k√P
Q = Flow (gpm)
k = Sprinkler k-Factor
P = Pressure (psi)
With a 5.6 k-factor and a minimum pressure of 7.0 psi (as is required by NFPA 13), we get a flow of 5.6 x √7 = 14.8 gpm
There's a wide array of k-factors available on the market, and a wide variety of minimum sprinkler pressures too. Extended coverage, residential, attic, storage, and ESFR all vary in required minimum pressures.
Driver #2: Area and Density (When Using the Density/Area Design Approach)
When reviewing cutsheets for sprinklers it's easy to take a k-factor and minimum pressure and assume that you then know the minimum requirements for a sprinkler and you're done. If you're using design criteria that only uses that approach, then you may actually be done.
However, if you're using the density/area approach of NFPA 13 then you also have to ensure the sprinkler is actually delivering the minimum density for the area its protecting.
It's easy to skip over this step. If you've ever laid out residential-style sprinklers, then you probably already know this.
Residential-style sprinklers can have small k-factors and relatively low minimum pressures to cover a reasonable floor area. However, these sprinklers can be used in NFPA 13, 13R, or NFPA 13D systems. 13R and 13D specifically can allow densities less than 0.10 gpm/sqft. The cutsheets often offer the minimum pressure for a given k-factor and floor area coverage, but the cutsheet may be assuming a 0.05 gpm/sqft density.
When we have higher densities (such as residential-style sprinklers in an NFPA 13 design), we have to consider this second driver for sprinkler flow.
The equation for density/area coverage is also straightforward:
Q = D x A
Q = Flow (gpm)
D = Minimum Density (gpm/sqft)
A = Area Covered by Sprinkler (sqft)
A sprinkler spaced at 15 ft x 15 ft with a minimum design density of 0.10 gpm/sqft requires a flow of 22.5 gpm.
With this, a k-5.6 sprinkler at 7 psi, spaced 15 x 15 feet with a 0.10 gpm/sqft density will actually need to flow 22.5 gpm.
Here's how this scenario looks when graphed:
The red line above represents the hydraulic pressure/flow relationship that a k-5.6 sprinkler offers. As the minimum pressure increases, the flow will increase. Similarly, as the flow needed through the sprinkler increases, the minimum pressure required to deliver that flow also increases.
For this scenario, the actual flow through the sprinkler must be the higher of the two amounts, or 22.5 gpm which will occur at 16.1 psi (see the blue lines above).
This means for a light-hazard, typical sprinkler we're demanding that the pressure at the sprinkler is over double what the code minimum is!
Will this difference break your calculation? No, it won't.
But let's look at another example where these decisions become a little more critical.
Take a Viking VK460 residential sidewall sprinkler. It's a 5.8 k-factor and has varying coverage areas with varying pressure and flow requirements.
Based on a 12 ft x 12 ft spacing, the minimum pressure required under the product data is 7.6 psi.
The Sprinkler-Driven minimum flow becomes Q = k√P = 5.8 x √7.6 = 16.0 gpm.
Assuming an NFPA 13 design, the Density-Area minimum flow becomes Q = 0.10 gpm/sqft x (12 ft x 12 ft) = 14.4 gpm.
In this scenario, the flow is Sprinkler-Driven. The actual flow through the sprinkler is driven by the k-factor and minimum pressure, and not the density/area point.
This same sprinkler, however, at a 16x20 spacing, looks a little different.
Based on a 16 ft x 20 ft spacing, the minimum pressure required under the product data is 20.1 psi.
The Sprinkler-Driven minimum flow becomes Q = k√P = 5.8 x √20.1 = 26.0 gpm.
Assuming an NFPA 13 design, the Density-Area minimum flow becomes Q = 0.10 gpm/sqft x (16 ft x 20 ft) = 32.0 gpm.
The demand through this sprinkler now becomes density-driven, and notice the actual pressure required to achieve this density is now 30.4 psi. If you have a poor water supply then these decisions can begin to really impact your hydraulic calculations.
Do you need to assess whether your sprinklers are driven by the k-factor and pressure or density/area? No - many hydraulic calculation programs cover this already.
These differences to become critical though with sprinkler selection, reducing the system demand, reducing the system pressure, and refining a design to end up with the most efficient system possible as an end result.
This Tool Available Now
If you're a Toolkit user, you can give this new tool a try today. Click here for online access to it.
This tool comparison tool allows different k-factor inputs, minimum pressures, density and areas with immediate graphed comparisons.
This tool will also be available for download with the latest Toolkit release here in a few weeks. More on that to come.
Thank you for reading and have a great, safe week!
While it is a basic question, the code path is somewhat complex. When does an elevator require fire sprinkler protection?
Today I'm exploring the code requirements for elevator sprinkler protection under the International Building Code (IBC) and NFPA 13. Here's a free PDF cheatsheet for navigating these requirements. To download, just hover over the image and click print or export.
A special thanks to Philip Valdez who sent over the suggestion to put this one together. I hope you find it helpful!
If you don't already get these free tools to your inbox, subscribe here. If you're having trouble viewing the image below, view it in your browser here.
If you've found this helpful, consider sharing it with a friend or colleague. As always you can subscribe and get more free tools like this at www.meyerfire.com/subscribe.
Thanks & have a great rest of your week!
Last spring I created a beta test tool for soffit obstructions to sprinklers. It was fairly basic using the dimensional rules for a soffit against a wall for a standard-spray pendent or upright sprinkler.
Thanks to some feedback and more input on this tool, I'm happy to debut it with new features. I've added code references from the 2007 to 2019 editions of NFPA 13, the different style sprinklers, and an updated visual diagram.
This tool is useful when there's a dropped soffit against a wall to determine whether the sprinkler will throw sufficiently underneath the soffit.
In the coming weeks I'll break out a code path for determining when each of these tools are used. For now, if you're familiar with the NFPA 13 Sections for Obstructions Against Walls then you'll recognize this tool's quick usefulness.
This tool stems from the Figures (b) and (c) for Obstructions Against Walls found in NFPA 13 Section 220.127.116.11.2 for Standard Spray Sprinklers, 18.104.22.168.2 and 22.214.171.124.4 for Extended Coverage Sidewall and Pendent/Uprights, and Sections 126.96.36.199.2 and 188.8.131.52.4 for Residential Sidewalls and Pendent/Uprights.
I'll have it hosted for free use for a couple months before it transitions to the Toolkit package. For today it's live here and on thecloud access for all current Toolkit users. Interested in getting access to every tool? Get the Toolkit here.
Know someone that might be interested in this tool? Send them a link! It's greatly appreciated.
Have a great week!
While being located geographically in the middle of the United States, it may not seem like seismic bracing would be a major concern. After all, we don’t have the frequency of intense earthquake movement that covers news headlines like the west coast experiences.
Despite the (fortunately) absent frequency, the New Madrid fault line runs near Memphis, Tennessee up to the bootheel of Missouri.
[Note: Yes, we Missouri-folk actually describe a portion of the state as a “bootheel”. When you say it aloud, though, you have to add a little twang.]
Back to seismic – this fault line has the potential for very strong seismic activity just as much as portions of California and the Pacific Northwest. As a result, seismic bracing is common for us in southeastern Missouri, in St. Louis, and even into central Missouri and southwestern Illinois.
As we move away from the fault line, at some point, seismic movement would be less severe – even to the extent that bracing isn’t necessary.
Where is that point?
How do we determine when seismic bracing is necessary for fire suppression systems?
Today’s article is covering just that. It’s an exercise I practice commonly as I essentially live on the boundary of where seismic is and is not required by code.
International Building Code References ASCE 7
Seismic bracing has roots in NFPA 13. As is the case between a “code” and a “standard”, however, NFPA 13 as a standard only tells us how to design and install the system. Code tells us when and where systems and components are required.
The International Building Code Section 1613 for Earthquake Loads requires that “every structure… including nonstructural components that are permanently attached to structures and their supports… shall be designed and constructed to resist the effects of earthquake motions in accordance with ASCE 7”. [2015 Edition 1613.1]
There are a few exceptions, most notably detached one- and two-family dwellings in some areas.
ASCE 7 Requirements Based on Seismic Design Category
ASCE 7, Chapter 13 (2010 Edition), for Seismic Design Requirements for Nonstructural Components, states:
ASCE 7 Chapter 13 addresses Seismic Design Requirements for Non-Structural Components. Its scope covers the minimum design criteria for nonstructural components (like fire suppression systems) that are attached to the structure.
ASCE 7 Chapter 13 suggests that seismic bracing is required for all structures, unless they meet an exemption. Section 13.1.4 specifically lists exemptions from seismic design requirements.
These Exemptions include:
Additionally, ASCE 7 Section 11.7 states that Seismic Design Category A need only comply with Section 1.4 (not Chapter 13).
So What is a Seismic Design Category?
A Seismic Design Category is a “classification assigned to a structure based on its Risk Category and the severity of the design earthquake ground motion at the site.” (ASCE 7 Chapter 11 Definitions)
In short, it’s a classification on the entire structure, ranging from A (least risk) to F (greatest severity).
Seismic Design Category A structures encompass buildings of ordinary occupancy located on sites with stiff soils and have little risk of experiencing earthquakes.
Seismic Design Category F, on the contrary, are required to remain functional following a strong earthquake, such as hospitals and emergency communication centers, and are located very close to major active faults.
What Impacts Seismic Design Category?
Several contributing factors are combined to give the seismic design category. They principally include:
Structures that are of high importance following an earthquake, such as a hospital, are of greater importance and carry a higher risk category.
Soil conditions greatly impact the ability of the building to response to motion. Stiff soil or rock conditions generally allow the building to better respond to an earthquake. Loose, stiff soil, or soft clay don’t give buildings the ability to move with the ground, and therefore create worse seismic reaction forces within the building.
Lastly, and probably the most obvious, the building’s proximity to a major fault line. The closer to a fault line, the greater the seismic forces from an earthquake event for the same earthquake.
How to Determine Seismic Design Category?
The International Building Code Section 1613 allows the Seismic Design Category to be determined either by IBC 1613 or ASCE 7.
The International Building Code Section 1613 details the step-by-step process to determine the Seismic Design Category. This involves using data from site soil testing, the Risk Category, and earthquake severity parameters from provided maps.
ASCE 7 has similar provisions in Chapter 11, detailing similar inputs of Risk Category, Mapped Response Parameters, and site conditions.
In practice, however, there are third-party tools that help make this process much easier.
Here are a few available, for free online:
With the Risk Category, Address, and Site Information, a Seismic Design Category can be quickly determined for a building. These reports also give important design parameters that will be used for Seismic Calculations for the design of the system.
What if I Don’t Know The Site Class?
With new construction, structural foundation design requires geotechnical testing and reports which give these values. The structural engineer will assess the report, and typically place the building’s Seismic Design Category in their front-sheet notes or in structural specifications.
This isn’t the case with interior remodels or work within existing buildings. No soil testing is done and sometimes no structural work is done.
When this is the case, the International Building Code requires a Site Class D to be used (IBC 1613.3.2). This could be made more conservative by the building official if geotechnical data determines that Site Class E or F soils are present at the site.
So Does My Building Require Seismic Design?
Back to the original question – once we know the Seismic Design Category, it’s easy to determine where fire suppression systems require seismic design.
If the Seismic Design Category is A or B, then Seismic Design Criteria does not apply. If the Seismic Deign Category is C, D, E, or F – then Seismic Design Criteria applies. Under this later scenario, all the requirements of NFPA 13 for Seismic Design now become an enforceable requirement for the system design.
Here’s a summary of the code path:
Seismic Design Criteria for Fire Suppression Systems depends upon the Seismic Design Category for the Building. This Seismic Design Category incorporates the importance of the building, it’s proximity to seismic fault lines, and soil conditions at the site.
While the determination path through codes & standards might not be as clear as other system requirements, seismic design is nonetheless a crucial component for the performance of a fire suppression system and an important consideration in the design of the system.
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Design-specifications have had a tradition and sometimes contemptuous past in the world of fire protection design.
Sometimes called “design-build spec”, “performance-specification”, “delegated design”, “deferred submittal documents”, “scope drawings”, or “design-spec”, these all mean relatively the same thing; the engineer is not providing a working submittal of how a fire suppression system should end up in the field.
Back in 2008 advocacy groups from the Society of Fire Protection Engineers (SFPE), National Society of Professional Engineers (NSPE), and National Institute for Certification of Engineering Technologies (NICET) adopted a joint position on the role of the Engineer and the Engineering Technician as they relate to fire protection systems. A summary and full-length document are here.
The position statement does a good job of identifying the relationship between engineering documents and a working shop drawing submittal. It maintains that the role of the Engineer is to support the proper protection of the public’s health and safety. A licensed Engineer is required to understand a broad sense of fire protection beyond just suppression, and also has specific state requirements for licensing and authorization.
While the position statement does a good job of identifying roles and defining the relationship between an engineer and a technician, real-world experience says that many “design-build specifications” fall short on good practice.
I’ll save my frustrations on the lack of quality engineering documents for another day (it is not a regional issue). There is a ton to explore on that topic.
I will however offer up what I like to use as a practical checklist for design-build specifications. Not all owners want to pay consultants to flush out all the details of a system. I get it. But if an owner is paying for anything at all, then the documents should address basic requirements and cost-impacting elements of design.
If a set of plans just outlines an area and says “per NFPA 13”, then someone isn’t doing it right.
This cheatsheet is a collection of the items I’m looking for when I help contractors bid jobs. It’s a shortcut to all of the items that have a design and cost-impact to a job.
If you, as a consulting engineer, address every single one of these items clearly and within code, then pat yourself on the back my friend, you are a gift.
If your documents don’t address each of these items (yes, including flow test information), consider making it a part of your regular practice. None of the items on this list are major time consumers, but by accounting for them you’ll allow better bidding from contractors and much less contention after bids are due.
Please, please: don’t loft up vague project requirements to contractors and hope for the best. Invest in being a knowledgeable and quality practitioner of this great industry. It'll more than pay itself back to you.
What are your thoughts? What type of bid documents are you used to seeing? Join the conversation and comment here.
Awhile back I researched and built a translator for various versions of NFPA 13.
It's built to quickly find where a code section has migrated between different editions of the standard. There's a free version here which connects the 2016 and the 2019 Editions of NFPA 13.
Based on feedback and the positive response to that tool, I've just finished a similar edition translator for all of the published versions of the International Building Code. It covers Chapters 1 through 11, 15 and 30. Here's a quick video of how it works:
If you're interested in giving this a try, you can get it as part of a 30-day trial for the MeyerFire Toolkit here. https://www.meyerfire.com/toolkit-trial.html.
It's been busy around here tinkering with new tools since I went on my own in October of 2019. I am not by nature a programmer, but as the son of two accountants I'm pretty sure Microsoft Excel is just in my blood.
I've gotten lots of positive feedback from users on the Toolkit and I'm happy to announce this week some major improvements aside from the new IBC translator:
1. A La Carte Tools Coming
Some users aren't designers or engineers and would only use one or two tools. I get it. In the next couple weeks I'll be breaking out individual tools and pricing them for less, separately. The first one offered this way is the Water Supply Analysis tool that will be up this week.
2. Instant Activation Codes
One of the biggest frustrations I've had on the development side is with quirky activation code servers. They drive me nuts. Over the past month I've dramatically simplified the process, so that new purchases automatically get clear activation codes exactly 2 minutes after their purchase. Clean and simple and it's working much better than before.
3. Toolkit Going to $195 in February
With over a half-dozen new tools, the price of the Toolkit is going up to $195 starting in February. If you're interested but haven't bought yet, pick up a license now and you'll lock in your $150 subscription.
4. New Licenses Are Multi-Device & Sharable with Coworkers
Lastly, based on the biggest piece of feedback I've gotten, with the $195 price-bump starting in February a single license will allow multiple installs, so that you can use on multiple devices and with members of your company.
If you have a design staff with multiple users, it only makes sense that you're able to use and share files with coworkers.
If you have a single-user license now and want to upgrade, shoot me an email at email@example.com and we'll get the upgrade set up. Should you want to learn more about the Toolkit, you can do so here.
Hope you have a great rest of your week!
Now that I live with one hand in creating shop drawings and the other in consulting, I don't come across this question quite as often as I had. In general, people don't call unless they know they need fire protection help.
When I worked for MEP firms, I came across this question all the time. As in evaluating this on every single project.
"Does the building code require a fire sprinkler system?"
The adopted building code is the first stop in determining whether a fire sprinkler system is required or not (not standards, such as NFPA 13). In the International Building Code, this is generally Section 903.2 for fire sprinkler systems.
You'd first determine your building occupancy (from Chapter 3), then go to 903.2 to see if your facility's footprint is large enough, has enough occupants, or meets the other nuanced criteria to bring in a fire sprinkler system. I have gotten caught ignoring the special applications - in my case a windowless basement that didn't have enough openings which drove sprinkler requirements. We got sprinklers in, just later in design than I would have liked.
This cheatsheet below is a summary of the requirements among various occupancies and other drivers for fire sprinkler systems, according to the latest IBC (2018 Edition).
It is worth noting that local code adoptions, insurance requirements, or the International Fire Code can also introduce the need for fire sprinkler systems.
As you may know I'm a fan of cheatsheets, so I hope you find this helpful. If you think it'd be beneficial to also cover other IBC editions, let me know in the comments here and I can get that moving too.
Thanks & have a great week!
Oprah had an annual favorite-things list. I've always thought that would be fun to do - except I can't offer everyone a Pontiac G6.
Sorry about that. My wife says the kids need to eat.
I will however continue to make lists of my own. This one isn't necessarily a "favorite-things" but rather interesting topics and tools I plan to keep an eye on for 2020.
A Long-Awaited Computer-Based PE Exam
The Fire Protection Principles and Practice of Engineering Exam (PE Exam) will finally become computer-based in 2020. This has been discussed for many years and will bring Fire Protection in line with several other disciplines and the Fundamentals of Engineering (FE Exam).
Likely a much bigger change to the 2020 Fire Protection PE is replacement of the treasure-trove of references (over 9,000 pages) into a single exam reference guide which is being developed by SFPE. This single resource will be all that is allowed in the exam room. While the exam focus and content should be relatively consistent from past years, preparation for 2020 will be a different challenge than in years’ past.
Around here, I’ve already been contacted by numerous people seeking the publish date on both the 2020 MeyerFire PE Prep Guide and the PE Exam’s Reference Book. The 2020 MeyerFire PE Prep Guide will follow the official reference book by a month (which is rumored to debut sometime in Spring 2020). I’m keeping my fingers crossed that the official reference book will be early enough to give everyone ample time (including instructors) to study and absorb it.
At least for 2020, the Fire Protection PE will only be given on a single-day (October 22, 2020). Going computer-based might someday afford year-round testing availability like the Mechanical PE Exam is starting this year. That will certainly be another interesting change when it happens.
The Fire Protection PE Exam's joining the twenty-first century with its first computer-based exam in 2020.
Viking’s New Window Sprinkler
Viking just released a new listed Specific-Application Window Sprinkler. Use of window sprinklers have long been a strenuous and often misapplied technology, but the new Viking lineup could offer additional options in this space. I'm very interested to see how the new sprinkler gets used in the market.
The brand-new window sprinkler is only the second entrant to a complex & niche application.
If you haven't checked lately, it's already in our live Sprinkler Database.
Have you seen it? I have. Nitrogen inertion is becoming more and more commonplace each year.
This year is the first I’ve seen a project specify a nitrogen-inertion system upfront with a dry-pipe sprinkler system. Finally!
As an industry I feel like we're all slowly learning and educating owners on the major cost-savings these can have, but until recently I've yet to see them specified on a project. It's good to see other consultants getting traction with owners on the topic.
Projects under the United Facilities Criteria (UFC 3-600-01) allow a hydraulic c-factor of 120 in dry systems with nitrogen included, which are now mandatory for dry systems. This is a great benefit I hope the NFPA 13 continues to consider adopting. It can be difficult enough to convey to owners the cost/benefits of avoiding corrosion in sprinkler systems with a higher upfront cost, but if we get a hydraulic kick-back for inclusion of nitrogen systems then the conversation could be made substantially easier with owners. Depending on the system size, a hydraulic benefit might help contractors to voluntarily provide nitrogen systems and save on pipe sizing throughout.
New & Better Tools for Revit
I live entirely in BIM (Building Information Modeling), so I’m always on the lookout for great Revit families, tools and workflows.
The past couple years have really ramped up the race for fire protection tools in BIM, including Victaulic’s Revit Add-In, AutoSPRINK’s RVT lineup, HydraCAD for Revit, and a few others. I’m very encouraged that there is finally interest in this space and that the developers in it seem to be doing very well.
Revit Add-In productivity-boosts have made even small projects like this home design
I completed in 2019 possible at a very reasonable time and cost.
I just started using the RVT platform in 2019 and have found major productivity boosts by doing so. If you use Revit and haven’t checked out these platforms, 2020 might be the year to check them out.
Why This Site Exists
I don't (usually) just write to entertain myself. I put together this site to help start the conversation on fire protection.
If you're relatively new around here - I'd like to introduce myself. I'm Joe. I'm no an end-all expert in the field, just a normal guy who loves being in fire protection. I worked for and learned under a couple engineering consultants before starting my own practice in 2019 where I now write, build tools and design full time.
This site is all about bringing together experts from the different corners of fire protection to discuss and share best practices. We're all about improving your workflow and your knowledge with resources and ideas - plus giving a medium for you to share your expertise to everyone's benefit.
Thank you for hangin' around and I look forward to sharing in a great 2020 with you!
This time of year is just the best.
I feel extremely fortunate to have three young kiddos at home, a supportive and all-around great family, and an extremely rewarding career in fire protection and doing what I do here at MeyerFire.com. Whether you subscribe, dabble occasionally on the forum, or just stop in to use tools here and there, THANK YOU for a really wonderful 2019.
One of the tasks of wrapping up a year is revisiting what resonated the most in 2019 of all the content here. If you just joined in this year or know someone who would benefit from this content, please consider sending a link.
I've been on a bit of a tool creation kick lately. Sorry, I just get excited sometimes.
This week I'm introducing a small portion of a much larger programming effort - this tool helps determine an adjusted fire sprinkler remote area based on the system type and density/area curves of NFPA 13. It can factor in the quick-response area reduction, sloped ceiling adjustment, double-interlock pre-action or dry increase, and high-temperature sprinkler decrease. I'll probably only have this up as a free version for a month or so before adding to it and incorporating the full tool in the Toolkit.
At the bottom of the tool you'll see a schematic remote area drawn with the parameters input. I'm using it when mocking up hydraulic calculations for estimation or when I'm first setting up a hydraulic calculation. Give it a shot and let me know what you think!
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Joseph Meyer, PE, is a Fire Protection Engineer in St. Louis, Missouri. See bio on About page.