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!
Wow a lot has changed in a week. We're holding on fine here, but I hope you and your family are safe and healthy wherever you are.
Now back to more fun things like fire protection -
After last week's debut of fire sprinkler requirements for elevators, I had a couple emailed requests for a fire alarm version. I love the idea and put some time into reviewing and organizing the requirements on the fire alarm side.
This first iteration is a draft, and if you're well versed in this arena I'd love for you to take a look and let me know what you think. Feel free to email me directly at email@example.com, or comment on it here.
In the upcoming week I plan to incorporate ASME A17.1 and it's impact on the fire alarm side of accounting for elevators, hence the big [DRAFT] watermark on this PDF.
Click on the image below to get a PDF copy of the Fire Alarm Elevator Cheatsheet:
If you know anyone that could benefit from this content, please consider forwarding them a link.
Hope you have a safe and healthy rest of your week! Thanks for reading.
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 184.108.40.206.2 for Standard Spray Sprinklers, 220.127.116.11.2 and 18.104.22.168.4 for Extended Coverage Sidewall and Pendent/Uprights, and Sections 22.214.171.124.2 and 126.96.36.199.4 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!
Things around here are always busy. The past few weeks have been no exception.
With feedback from some Apple users, field-users, and those without Microsoft Excel - I've heard your pleas!
We now have every single tool from The MeyerFire Toolkit now available online to subscribers! You can see the complete list of tools at www.MeyerFire.com - just hover over the "Tools" list.
Now, you don't need Excel or a Microsoft operating system - access the quick tools you need from anywhere, anytime.
Not a Toolkit subscriber? Join on here. Licenses are now multi-user so you can share these tools with your whole team.
SFPE Atlanta March 10th & 11th
If you're attending SFPE Atlanta's regional conference on March 10th & 11th - let me know! I'll be there for John Frank's daylong session on updates with the Fire Protection PE Exam. He's the longtime leader of SFPE's Online PE Review Course and we'll be doing some collaboration in preparation for the computer-based changes to the PE Exam in 2020.
NFSA Annual Conference April 29th - May 1st
If you'll be in Phoenix for NFSA's National Conference - check us out! I'll be teaming with the voice of the fire sprinkler industry - Fire Sprinkler Podcast's Chris Logan to speak on New Media in Fire Protection.
In Phoenix we'll be dissecting what we've learned while starting up different media in the industry, what projects we're working on now, and what ways we all can capitalize on new opportunities in the media space. That presentation is set for Wednesday April 29th.
Making the Jump - The New Consulting Practice
For all those who have reached out on LinkedIn about my (relatively) recent jump into starting my own design practice - thank you!!
Things have been very busy with a healthy amount of fire sprinkler shop drawing design & consulting work.
If you have interest in following the work I'm doing as part of that endeavour, follow my updates here: https://www.linkedin.com/company/meyerfire/. There's a fresh video on a recent all-BIM sprinkler design.
If we're not yet connected on LinkedIn, consider doing so. It's GREAT to hear from and chat with other passionate people about the fire protection industry and it's something I really enjoy.
As always, thanks & have a great rest of your 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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We love to poke fun at millennials. It’s like the holy grail of tradition.
“Kids coming out of school these days – you know? It’s ridiculous. They want twice the pay and half the work of when I came out of school. They don’t want to learn. They’re lazy. There’s not enough talent. There’s not enough interest. They don’t work hard.”
Ever heard that before? How about this one -
“Young people think they know everything, and are always quite sure about it.”
Yeah – that last quote wasn’t exactly about millennials – Aristotle wrote it in the 4th Century BC. Every young generation is clearly, obviously, unexplainably worse than the one before it. Right? I mean criticizing the next generation has been going on for all human existence. I’m sure cavemen used to scorn at how the young have no eagerness to strike rocks anymore…
Millennials are so… entitled.
Yeah – I wrote it. Entitled. The worst label of all. That E word.
Millennials are so entitled that they don’t even own their own issues; those are of course caused by Boomer parenting. [see the half a million search results for “millennial poor parenting” on Google].
I mean clearly millennials are like the worst young generation we’ve ever seen? Right?
Back Off Another Joe/Millennial Soapbox
OK. So maybe the problem isn’t that bad. Maybe I exaggerate a little. Maybe I write too much in the third person considering my age technically qualifies me as a millennial. And yes, maybe I do also blame my parents for all my nonsensical fears (thunderstorms and sinkholes, come on Mom!).
I was probably accused of being entitled a couple years into my post-college career. I felt good about the work I was doing, felt like I was understanding the curve, and I am sure it was showing in my attitude. A couple big project issues plus a bad annual review and I was quickly sized back to reality.
But entitlement doesn’t go away easily.
It was around that time that some coworkers went to a career fair at an area state college. One of the college students (a junior) inquired about the company. He got the normal pitch on working culture, opportunity, training and the whole bit. He then asked about management positions. After laughing it off my coworker realized the student was serious. He was looking for a management position as a quasi-21-year-old with zero real world experience!
After returning to work and sharing the disbelief, it’s easy to see entitlement in others when at that same time I probably couldn’t see it in myself.
I did get over it though. It wasn’t through shame or being a “company guy” or bad annual reviews. It was by starting my own side-hustle.
Takeaways from the Art Shop
I had always enjoyed creating sketches. During college I had a few architectural studio courses where we learned architectural sketching traditions. I enjoyed drawing and took some of those lessons to open a small art shop online.
That experience brought so many positive perspectives into my life.
It started with only one sale in the first two months of opening. It was a wonderful feeling. Then one good review led to another sale in month three. In month four I had two sales. Month five I doubled again.
With each touchpoint I worked on improving the customer experience. I learned quickly to be responsive to customers. I learned how to deal with unsatisfied customers – which meant putting frustrations aside and owning-up to every misstep. I learned how taxation is theft (ok not really – but it is a major downer).
Probably one of the most important things I learned from the basic art shop is that I had to take ownership of the work result. It never mattered how hard I tried to draw. If I created something that offered no value to others, it wouldn’t sell and had no value. That’s the real-world economy.
People pay for value. How was I to bring value to a customer? How could I improve the value I offered? How could my presentation and correspondence be improved to help convey value? I thought about all of those things, constantly.
That also began slowly translating to the workplace. Just because I put in effort – if the end result was incomplete, sloppy or just wrong – then I was not producing value.
The essence of entitlement is believing that showing up is enough. It’s not. The value we provide for the world is our all-in engagement with doing great work.
Employee vs. Ownership Perspective
Starting that art side-hustle slowly and fundamentally changed my perspective about business and serving people.
As I see it – there exists an Employee and an Ownership mentality. An Employee mentality asks – “why doesn’t our company pay for X?”, “they underpay everyone here”, “they never pay for good software”, and on and on.
The Ownership perspective is looking holistically at the business. “How can we better serve our clients?” “How can we improve work culture?” “How can we improve productivity?” An Ownership mentality links personal responsibility to their work and representing a brand.
I didn’t have to have a stake in a company to begin to develop that perspective. Businesses exist to make money. If businesses didn’t make money for a long period of time, then they fold and cease to exist. That’s reality, and that’s not a bad thing either.
But just adopting an Ownership perspective brings about a world of possibilities. Company limitations don't become obstructions - they just become a problem that needs a creative solution.
That art business grew, and grew and grew. Just three years in I sold over 600 pieces in a year. Wild. Especially for an ameateur artist who's dayjob is being and engineer. That shop still exists at www.etsy.com/shop/artbyjosephdalton. There’s not much time into it anymore now that the fire protection content is top priority – but I’m so thankful I started that shop because the lessons it taught has been invaluable.
Want to change your perspective? Start that side hustle you’ve always wanted. It just might unlock a fresh way of looking at the world.
Enjoy this article? Here are other career-related articles:
Being Deliberate About Your Future
Does Your Job Title Matter?
Knowledge is Not Just in Education
Fahrenheit 451 & The Thirst for Knowledge
Heartache of Failure in Life Safety Design
Enjoy this? Consider sharing with a friend.
Last week we explored when duct-detectors are required under the International Mechanical Code (IMC).
While the IMC is the most commonly-applied standard in the United States, it's not the only standard that dictates terms for duct detectors. Many international projects under NFPA 5000 or government facilities under Unified Facilities Criteria (UFC) pull in smoke detection requirements from NFPA 90A.
This week's post covers a cheatsheet for duct-detection requirements under NFPA 90A. Selfishly I've been wanting a quick go-to when covering fire alarm design, and now I'll have a copy for the two most common standards.
Around here we laminate cardstock color prints for these cheatsheets. If you'd be interested in purchasing a set of cheatsheets, let me know by commenting here. If there's enough interest I'll set up something in our store.
Thanks & have a great week!
On every project containing fire alarm design I come across the same question repeatedly - does this unit require a duct detector?
In short, there's two prevailing standards that determine whether duct detection is required. The first (and most common in the United States), is the International Mechanical Code (IMC). Section 606.2 identifies areas where smoke detection is required for the purpose of mechanical unit shutdown.
The other prevailing standard is NFPA 90A, the Standard for Installation of Air Conditioning and Ventilating Systems. I'll address those requirements in a later post.
Back to the question at hand - there's essentially six different scenarios a mechanical unit can fall into under the International Mechanical Code. These do not include the requirement for multi-level duct risers over 15,000 CFM, but rather whether an individual unit requires detection at the unit.
Here is a quick cheatsheet summary concerning those scenarios:
If you review or design fire alarm systems regularly, take a look and let me know what you think.
If you know someone who might also benefit from cheatsheets like this, send them a link or tell them to subscribe here.
Hope you find this helpful and have a great rest of your week!
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.
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Joseph Meyer, PE, is a Fire Protection Engineer in St. Louis, Missouri. See bio on About page.