A quick update this week - back in 2018 I put together a flowchart for when sprinklers are required in closets. It was nice and had some nice feedback, but it only pertained to the 2016 Editions of NFPA 13, 13D, and 13R. This week I went back and made some major updates for references from the 2002 through the 2019 Editions for each of these standards.
This cheatsheet is a little more printer-friendly (11x17) and simplified to the NFPA 13, 13D and 13R standards.
If you're a fan of these cheatsheets and flowcharts, check out the Toolkit. For a limited time we've set up an instant-download of all the latest cheatsheets immediately when you subscribe. If you're already a subscriber, great! Just login for the link.
Hope you have a great rest of your week!
Quick but big post today - we've just completed our most-requested tool to date - I'm happy to announce the System Estimator.
We've taken the Remote Area Analyzer (free online, here), added in hose allowances, main losses, elevation losses, riser details, and underground for an estimator tool that allows k-factor, spacing, density, system type, etc with updated system pressure and flow demands, all in real-time!
Check out a very rough video snapshot of real-time pressure and flow updates here:
If you're a toolkit subscriber - great! Get the new tool right now by clicking the download link below:
If you're not a Toolkit user, grab a free trial here: https://www.meyerfire.com/toolkit-trial.html. If you've signed up and don't get an automatic email with your trial activation code, shoot me a quick one at email@example.com and I'll get you set up with the 30-day trial.
Have you ever needed to do a quick estimate for a job, and not had a couple spare hours to lay out and calculate a system?
Even for a very basic remote area, laying out sprinklers & pipe, adding fitting, flow, control valve, and backflow losses, a source, and then hydraulically calculating is smoothly - easily can take an hour or more. Now take that same design and change it to a dry system, or at a different density. If you're like me, tweaking sprinkler spacing, k-factors, sprinkler heights, remote area sizes, and c-factors alone can take significant iteration just to get an idea of pressure & flow demand.
With this new estimator you can adjust all of those items in one-click, and see the immediate impact of each decision. It's built for estimators, but it can be a very helpful tool for new designers & engineers to quickly grasp design decisions well before a system has to be completely laid out and detailed.
Any feedback, let me know! As always, thanks for reading & have a great rest of your week.
The community here is second to none - after a post on my personal list of ideas for getting 'unstuck' in hydraulic calculations last week, I received a handful of encouraging emails and a string of great commentary.
Being an engineer and a son of two accountants, I can't help but turn those everything into a spreadsheet. With the tips last week and great feedback sent in, here is a PDF tipsheet that includes a quick rundown of ideas to consider when fine tuning and getting 'unstuck' while running fire sprinkler hydraulic calculations. Click the image or link below to download.
If you haven't already subscribed for tools & cheatsheets like this, you can do so, for free, here.
Thanks & have a great rest of your week!
Have hydraulic calculations ever kept you up at night?
I can usually tell when I’m carrying extra stress in my life because my nightmares looks suspiciously like a hydraulic calculation that, despite any refinement, just doesn’t calc’ out.
Ever had that?
I’ll refrain from sharing all my personal issues for now, but if you’re a sprinkler designer or FPE, you’ve had to experience a project where there’s seemingly no way to get the hydraulics in the black.
When I initially lay out a project I’ll have a rough idea of pipe sizing and layout type (tree, grid, loop) based on similar projects. I’ll lay out a remote area and ‘rough-in’ the rest of the design so that I can get to hydraulic calculations iterations as early as possible.
Iterations? Yes, iterations.
If you’re long versed in the sprinkler industry this needs no explaining. If not, the secret sauce of a high-value designer/engineer is all in the refinement and iterations.
If you’re a consulting engineer, perhaps you’re less interested in whether a system is efficient and more interested in whether a system ‘can work’.
If you’re on the install side of the trade, you can earn back good pay and more by calculating systems that are well optimized – that is – perform efficiently, use the right system type, sprinkler type, and allocate pipe sizing appropriately.
This week I’m running down a quick list on potential avenues to consider when you’re working through those calculations and need ideas on tweaks that could help.
A quick disclaimer – hydraulic calculations are an important part of ensuring that the systems we design will be effective in suppressing a fire. The categories below are important aspects to consider when conducting hydraulic calculations – not corners to cut – but rather ideas to get unstuck in optimizing a sprinkler system.
Probably most important consideration is the system type (grid, loop, or tree). Dry and pre-action systems have limitations (no grids allowed), but if a facility is big enough then moving to a loop or grid configuration may significantly help the system perform more efficiently (ie: smaller size pipe).
This perhaps could be the most often-overlooked impact on a sprinkler calculation. Are you using the right k-factor for the job?
If you’re always using K5.6 until you get into storage applications – there are better tools for the trade. Adjusting the k-factor based on the density and sprinkler spacing directly impacts the starting pressure within a hydraulic calculation.
If you haven’t tried it yet, use this tool that’s a part of the Toolkit to find the optimal k-factor for your job.
Perhaps the most obvious and classic go-to is adjusting the size of pipe diameters. The larger the pipe diameter, the easier (less friction loss) the water will experience when passing through the pipe.
This isn’t always negotiable – many specified projects will stipulate a pipe wall thickness – but be cognizant that the pipe schedule is (1) correct for the job, and (2) is considered in the hydraulic calculations.
I had long underestimated the impact that pipe schedule had on hydraulic calculations, but it’s major. Schedule 40 and Schedule 10 can have a major impact. Change from Schedule 10 to Schedule 40 and you’ll increase friction loss by 24%.
See the impact on friction loss with the Friction Loss Calculator as part of the Toolkit here.
Also not a negotiable part of a project – c-factor directly relates to the friction loss under the Hazen-Williams method of hydraulic calculations – its nonetheless important to get correct.
How can you improve the c-factor? The pipe type (plastic, copper, ductile iron or steel) and system type (wet, dry, pre-action, deluge) will impact the c-factor.
One project I worked on had major challenges, including a quadruple-slam of dry system, sloped roof, tall roof, and poor water supply. The only suggestion we had to avoid a fire pump was to insulate and heat the building such that a wet system could be used. That change had a number of impacts, but the c-factor change from 100 to 120 for the pipe had a major bearing on the new system working.
One major change that’s coming to the 2022 Edition of NFPA 13 is allowing a C-Factor of 120 to be used on new dry systems that are installed with nitrogen. I’ll be sure to explore this in more depth when the time comes.
Are your sprinklers maxed out at the greatest possible coverage area?
In some applications, this can hurt more than it helps. Yes, we might save on the cost of material and labor with a reduction in sprinklers, but reducing the area per sprinkler in a very tight calculation can have a positive impact with starting pressures and the densities achieved.
See the density vs. k-factor calculator as part of the Toolkit to see the impact with various sprinkler spacings.
Remote Area Size
There are some reductions in allowable remote area size in NFPA 13. A common one is the quick-response reduction, which allows a smaller remote area size for systems which have low(er) ceilings and quick-response sprinklers.
See the impact of remote area with the Remote Area Analyzer here.
Water Source Height
An often overlooked part of the calculation that has a major bearing on the result is the height of the water source. Many systems are designed based on a fire hydrant flow test. Is the elevation of that source accurate, relative to the jobsite?
I once worked on a job where a submittal showed the source (city water grid) to be at an elevation of 0'-0" relative to the first floor of the building. I charted google earth and paid close attention to the listed source from the flow test report. While a hydrant existed about at ground level elevation, the actual static/residual hydrant where the test results were gathered was at an elevation 27-feet below the project grade. It was a substantial hit to the hydraulic calculations (all calculations failed with the correct elevation shown).
Backflow Preventer Loss
On many systems the backflow preventer presents the worst pressure loss for any single piece of equipment on the system. It's easy as a designer to input a curve or a conservative static loss, run the calculation, and not return to the backflow preventer.
However, if you're seeing high pressure losses, shop around. There are a variety of backflow preventers on the market, and using backflows that are straight (horizontal/vertical, not N- or Z-type) and use OS&Y valves instead of butterfly valves can offer some hydraulic savings.
There's a whole database we've created on available backflow preventers as part of the Toolkit here: BACKFLOW DATABASE*
Just like backflow preventers, valves introduce pressure loss into the system. An OS&Y valve will remove the water-blocking paddle from the water stream, allowing water to pass through mostly unimpeded. Other valves like butterfly valves leave the paddle in place, causing some pressure loss.
Sprig, Drop, On-Pipe, Flexible Drop & Return-Bend Configurations
Ever looked at the difference between using sprigs and not using sprigs (on-pipe fittings or outlets) has on a calculation? If you're at a higher density, it can be significant.
Hydraulic calculations are usually not a driver in whether sprigs are used, or whether return-bends vs. side outlets vs. bottom drops are incorporated - however - these have an impact on the calculations and can introduce pressure loss in between the sprinkler and the branch pipe.
One notoriously high friction loss arena is use of flexible drops, which can add pressure loss with equivalent 1-inch pipe lengths of 20-70 feet of pipe. These friction losses can vary significantly among manufacturers and models.
Riser Nipple & Sprig Diameters
Have a storage calculation with high densities and a high sprinkler k-factor? It may be worth adjusting the sprig diameter to see the impact of the 1-inch diameter pipe.
Similarly, riser nipples in-between a main and branch line bear the full flow from the branch line to the main. These pieces, while many times shorter than the spacing between sprinklers, can still introduce a pressure loss to the system that a stepped-up diameter can help.
Special Application Sprinklers
Lastly - is there a sprinkler specifically designed for the application you have?
Many manufacturers over many decades have dialed-in and created sprinklers that are built for specific purposes (special application sprinklers). These product listings can allow different starting pressures and design criteria, which, as a whole, can help reduce the water burden on a system.
Two that I often use that come to mind are residential and attic special application sprinklers. In both cases, use of those sprinkler types within their respective hazards dramatically reduce the water required at the remote area, thereby allowing smaller mains and equipment back at the riser.
See a list of all available sprinklers on the market (filter & search) on the Sprinkler Database in the Toolkit.
In the next post I'll look to put together something that's a little more handy as a checklist for entry and intermediate designers.
In the meantime - what am I missing here? What aspect of hydraulic calculations do you think are often overlooked yet carry a big impact?
A couple years ago now (back in normal times) I wrote an article on when sprinklers are required in bathrooms.
I'm happy today to share that I've made some updates to the original cheatsheet, adding in references to the 2021 IBC, 2021 Edition of NFPA 101, and 2019 Editions of NFPA 13, 13R, and 13D. Take a look & download the cheatsheet here:
This week I spent a little time revisiting a post from earlier this year that broke out various requirements for components on floor control assemblies for fire sprinkler systems. A couple minor updates, but figured I would share. Thanks to Colin Triming for the tips on updates to this one!
Hope you have a great rest of your week!
If you work in and out of the residential design space, you may come across this question quite a bit.
A couple of years ago I wrote on this topic and put together a brief summary of the differences from a design and code perspective. This one gained a lot of traction and attention, and was included in the National Fire Sprinkler Magazine's Member takeover in the September/October 2020 Edition.
An updated cheatsheet is attached and includes some great feedback I've had since that 2018 article. Thanks & hope you have a great weekend!
Things are back - now that the PE Prep season is (mostly) passed, I'm turning attention back to a backlog of fun fire protection tools and ideas to share with you.
Today's tool comes from an idea sent in by Gerald Ebeling, Owner of 3D Fire Design in Texas.
It's a new Domestic Demand Calculator - it can turn fixture counts over to a domestic demand in gpm or L/min - or you could hand count plumbing fixtures and calculate a domestic demand yourself. It works with the 2002 through 2019 editions of NFPA 13R and with both US and SI units.
Things are back - now that the PE Prep season is (mostly) passed, I'm turning attention back to a backlog of fun fire protection tools and ideas to share with you.
This week is a new Domestic Demand Calculator - it can turn fixture counts over to a domestic demand in gpm or L/min - or you could hand count plumbing fixtures and calculate a domestic demand yourself. It works with the 2002 through 2019 editions of NFPA 13R and with both US and SI units.
Why Calculate Domestic Demand?
For a combined service entry serving both fire suppression and domestic water needs, the flow through the combined main will include flow that is already happening on the domestic water side. Faster water movement will create more friction loss.
When a combined service is 4 or 6-inch and there's only a couple restrooms - the demand for a fire sprinkler system will likely be far higher than the domestic will ever need.
However, for smaller residential systems, the domestic demand could be as much if not more than the sprinkler demand. A combined service that serves both these purposes will need to take the domestic demand into account.
There is a workaround for this though - automatic domestic shutoff valves can direct flow to the sprinkler system and automatically cutoff domestic demand during a fire event. If these are used, NFPA 13R says that domestic flow doesn't need to be considered.
In all other cases, NFPA 13R states that domestic flow through the combined portions of the main do need to be considered and calculated for a fire sprinkler system.
The New Tool
The Domestic Demand Calculator will be included in the next update of the downloadable MeyerFire Toolkit. For the next couple months, I'll leave it up on the site for free access for everyone. Give it a try and let me know what you think!
Thanks and have a great week!
What a weird year for 2020.
Last year I thought this would be somewhat of a wild year for Fire Protection PE Prep - with the major computer-based changes, references changes, and question styling changes. That prediction ended up being too modest as we've had a total of 12 changes to the exam references (either removing, adding, or changing year editions) that shook up the prep space.
Yet, that of course was hardly the biggest shuffle this year. For the first time, the Fire Protection PE Exam is getting a second day in January (January 12th, 2021) due to limited capacities (re: Covid) in the testing centers on the original October 22nd date.
For those who are preparing for the exam and are in the PE Prep Series, all of the access for those exams are now extended through January 2021.
Thoughts on 2020 Prep Season
If you know someone taking the exam this year (...or in January), send them some flowers or ice cream or chocolate... if they're like many I've spoken with they probably feel like guinea pigs with all the changes, plus the uncertainty of actually being able to take the test, all on top of the normal uncertainty of whether all the preparation over the summer has been enough. That's rough.
Around here there's been so many changes due to the exam. The Prep Series was pretty much overhauled, as was the 2020 PE Prep Guide. Just this year over 150 questions were written or re-written to match the new exam specifications.
Along with those overhauls comes the pain of errors in those questions. I've been thankful for the loads of input and feedback since I first wrote the guide in 2016. Each year up until now the number of errors and tweaks found in the books has gone down... up until the 2020 edition. It's discouraging on my end when we find errors in the material, but that's nothing compared to the frustration for an examinee that doesn't have reliable content. My goal when I started the Prep Guide was to continually improve it year over year, and try to be as open and transparent as possible when it comes to getting the material right.
If you have a Prep Guide and haven't seen it yet, I've posted errata and have made updates to it throughout the year. It's located here: www.meyerfire.com/errata
I very much appreciate the feedback from examinees, especially with so many changes to the guide and online content this year.
Next Year & Continuing the PE Prep
Helping with PE Prep materials has been extremely rewarding for me. I saw a positive review online the other day that said the value of the materials is well beyond the cost. The review mentioned they hope I don't raise prices to match other content out there...
I got a good laugh and am very happy to report that I have no intent to raise prices for future years.
The whole goal here from getting into PE Prep a few years ago was to be sure that there is quality, affordable content for Fire Protection examinees. It was extremely frustrating to me when I took the exam that the materials were so expensive and that there just wasn't a lot of great content at the time. My whole goal here it to try and mend that gap with helpful material that is reasonably priced. I certainly hope that's the case now and the case going forward.
Frequently Asked Questions on Scoring Correlations
I've gotten maybe half a dozen questions asking about how close question difficulty comes into play, and how a score on a MeyerFire exam compares to scores on the actual PE Exam.
There's a ton to discuss here, but I'll try and pick off a few key points. First, is that with the data I've compiled, the average score for an examinee across the 20-weeks of the PE Prep Series is typically close to the raw score on the actual PE Exam. Meaning - if someone has averaged a 7.5 out of 10 on the PE Prep Series questions, they tend to score roughly 75% on the actual exam.
Historically I've connected these points from examinees who have reported their scores back and matched it up with the different data points taken in the PE Prep Series.
In general, exam day will feel closer to a new PE Prep Series exam or the full-length exam in the Prep Guide than it will to the 4-hour review exam or the 8.5-hour review exam in the Prep Series. In both of those longer online exams, the questions are review-only and you've already seen content that is the same or similar. There's a noticeable boost to your score on those review exams that aren't reflected in the PE Exam.
Also, just because we typically see a matching range on average Prep Series scores to the actual exam doesn't mean that it is always the case. There are always exceptions here both ways (people scoring much higher than the Prep Series, and people scoring lower).
All that to say - regardless of how you've tested so far - don't be discouraged by your scores. Go into exam day with confidence that you're going to give it your best effort and just see what happens from there.
Oh, where has Joe been for the last few months? Other than question writing and posts on the Daily Forum page - I've been working on an awesome project that has just debuted - if you haven't seen it check it out here.
My hope in the coming weeks as the PE prep settles down is to hop right back in and continue to work on some new tools and tool improvements around the website going forward.
Hope you and yours are safe and healthy and that you have a great week.
Awhile back I mentioned there were some big projects in the works around here. This has been Number 1 on my list for over a year now.
Last summer I threw out an idea that took hold, and since last November I've been thrilled to be a part of a project that I think will be a major help for industry professionals.
The National Fire Sprinkler Association (NFSA) has published informal opinions on everything fire sprinklers for longer than I've been alive. Their Expert of the Day program answers real questions to the 'gray' areas of code with practical advice from leading industry experts.
While these opinions have been collected and published monthly for decades, up until now they've never been assembled, organized, and published into a single resource.
I'm thrilled to announce that this collection of expertise is now complete; the NFSA Expert of the Day Handbook is a two-volume, hardcover set of over 1,300 pages covering nearly 2,000 questions on over 585 topics relevant to fire sprinkler systems, standpipes, water supplies, inspection, testing, maintenance, codes and standards.
Why am I so thrilled about it? I had the pleasure to work with NFSA by collecting, converting, and organizing all the expert inputs into these volumes. This was a concept I really wanted to see happen - and after sharing the idea of compiling the years of content to NFSA they were happy to fold me into the team on this project.
It's now available for pre-sale with shipments starting in just a few weeks (late August / early September).
If you are a sprinkler designer, engineer, inspector, installer, plan reviewer, code authority, or work in and around the fire sprinkler industry, then this handbook was built for you.
Just in the eight months of reading and compiling the information I saved days of code research (thousands of dollars in billable hours) by having quick access to these expert opinions. Just as it is part of the mission of this site, I am wholeheartedly excited to see how these handbooks help promote best practices and share expertise with the industry.
Check out more about this two-volume 1,300 page set and get a copy today.
Questions? Comments? Shoot me a line at firstname.lastname@example.org.
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Joseph Meyer, PE, owns/operates his own Fire Protection Engineering practice in St. Louis, Missouri. See bio on About page.