I've heard that in order to publish on the internet all blog post titles must have a gripping click-bait title. This was my best attempt. Sorry to disappoint, but there is no love story here.
Things are back on track this week - the last got a little busy at home last week when my wife and I welcomed our third child to the family. Even with the third, it's amazing how much joy and motivation kids can bring with their arrival.
Needless to say I didn't have a whole lot of productivity last week, but I'm very glad you've tuned in. This week we're exploring requirements and challenges of sprinkler protection near overhead doors.
Sprinklers are required under "fixed obstructions over 4 ft (1.2 m) in width." (NFPA 13 - 2002-16 184.108.40.206.1, 2019 220.127.116.11.1)
One common application for this code section is overhead doors in the "open" position. Annex material even specifically references overhead doors as an applied example of this requirement.
Sprinklers are required where the horizontal projection of an overhead door exceeds 4-feet.
Application of the 4-ft Obstruction Rule
If the overhead door doesn't create an obstruction over 4 feet (1.2 m) in width, then a sprinkler is not required to be provided beneath the door. This dimension is typically applied in the horizontal dimension only, and is measured as the horizontal projection of the edge of the door away from the wall.
Depending on how creative things want to be architecturally, sprinklers can be avoided beneath overhead doors when the door assembly doesn't create a 4-foot horizontal obstruction. This can be the case with small coiling doors, door tracks that only run vertically up a wall, or a combination of vertical and horizontal tracks that don't project more than 4 feet out away from the wall.
Hanger & Supporting Challenges
NFPA 13 does not specifically address support for sidewall or upright sprinklers below an obstruction, but similar requirements can be extracted from criteria on pendent sprinklers served by branch pipe above a ceiling.
If a sprinkler's horizontal steel branch pipe feed is greater than 1'-0" for systems with 100 psi or more, or greater than 2'-0" for any steel system, then a hanger is required to support the armover (NFPA 13 2002-16 18.104.22.168, 2019 22.214.171.124).
This presents a natural challenge as the door track is typically only designed to support the forces of the door and is not considered to be building structure capable of supporting the sprinklers, pipe and fittings. While it's very common for installers to attach the hanger to the door track, many see this as a violation of the hanging rules of NFPA 13.
Supporting sprinklers beneath the overhead door can be a challenge due to the height differences between the door and the ceiling/roof structure above.
Drainage & Dry Systems
Protection beneath overhead doors ramps up to another level of difficulty when used in dry systems. If a sprinkler beneath an overhead door on a dry system traps water, there needs to be a means to drain the trapped water and for dry systems in an unheated area, would require an auxiliary drain and drum drip.
While this might not present a challenge with a single overhead door, multi-bay vehicle buildings could wind up having a low-point drum-drip for every or nearly every other overhead door.
Aside from the cost, these drum drips are a maintenance nuisance as failure to drain these on a regular basis could result in a freeze and rupture of the drain assembly.
New Guidance on Sprinkler Position & Types Below Obstructions
Fortunately - in an update that I find very helpful - the latest edition of NFPA 13 now addresses where sprinklers can be located beneath obstructions.
Sprinklers are required to be either located beneath the obstruction, or with their deflector no more than 3 inches off the side of the obstruction (see below). This was clarified in 2019 based on fire testing & research.
New guidance for sprinkler protection beneath obstructions - new to the 2019 edition of NFPA 13.
Where a sprinkler is adjacent to the obstruction and not directly beneath, it must be an "intermediate-level rack type" (NFPA 13 2019 126.96.36.199.1.3). These sprinklers are provided with a shield that prevents inadvertent cooling from sprinkler discharge above (the shield is ineffective and not intended to help "collect" heat).
What tips & tricks have you come across when dealing with sprinkler design around overhead doors? This site is created to start the discussion. Add your questions, tips & tricks in the section for your comments here.
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I've been told that memorizing the ANSI and ARCH drawing sizes along with architectural scales & their scale factors is a part of the first day of any drafting program. I've also been told that anyone who drafts regularly should undoubtedly have the standard sheet sizes and scale factors for different architectural scales memorized.
Consider me the dumb exception who never learned how to draft.
Despite being told I have a large head (I think they're talking about my physically awkward-sized head and not my bloated ego), I can't seem to allocate much space in there to remember the essentials of life like knowing that ANSI D translates to a 22 x 34 sheet size.
And for that, I've created a drafting cheatsheet -
Normally only important images get a caption below it, but in this case even a very basic table that just shows architectural scales and names for drawing sheet sizes gets a caption too. What a day.
Now, if you're from a part of the planet that uses an intuitive, logical, consensus-driven, and straightforward method of measuring using the SI system, then you can largely ignore the above tool and write us English-traditionalists off as keeping our head buried in the sand.
Despite even the original developers of the English system of measurement overhauling their system twice (the British adapted to the imperial system in 1824 and the metric system in the 1960s) and ditching the foot-pound world, us westerners just can't seem to let some things go.
This shouldn't be the sword I choose to fall on, so I'll leave the dead horse for someone else to beat. For those who use the "US Customary Units of Measure" and also can't seem to recall how to scale a 3/32" = 1'-0" background properly (it's a scale factor of 128), this cheatsheet is for you too.
Interested in getting more weekly tools & articles like this? Subscribe, for free, here.
This week we're covering a basic riser manifold configuration for wet-pipe fire sprinkler systems. This is not for a shotgun-style single riser, nor for a wet riser using an alarm check valve (we'll explore both of those later).
If you haven't checked it out, there are great ongoing discussions (some of which covered these topics) on the MeyerFire Daily page here.
Wet-pipe systems form the backbone of traditional fire sprinkler system design, comprising the most popular and most economical system type available. Here's the major components that go into a wet-pipe fire sprinkler assembly:
Hope your 2019 is off to a great start! Here's the big industry impacts I'm excited to be following in the upcoming year.
Tyco's UL Certified Antifreeze Solution
Tyco (Johnson Controls) debuted a big industry shakeup over the end of 2018 with their new UL Certified pre-mixed antifreeze solution.
A tragic apartment kitchen fire in 2010 activated a nearby sprinkler as part of an antifreeze solution with too high of a glycerin concentration, resulting in an "explosion" when contacting the flame. This and two other incidents quickly prompted an investigation by NFPA and its Fire Protection Research Foundation, which resulted in TIAs (Tenative Interim Amendments) to limit the use of antifreeze in new sprinkler systems. These TIAs required that antifreeze solutions must be listed for use in sprinkler systems.
Until now (eight years later), no such listed solution was available on the market.
This new antifreeze solution offers an alternative to dry systems for temperatures as low as -10 deg F (-23.3 deg C), and are listed for use with CPVC.
Upcoming PE Exam Changes
While the 2019 Fire Protection PE Exam doesn't appear to hold any major changes from the 2018 version, this is the last year that is planned to be a pencil and paper, all-resources-allowed version of the PE Exam. In 2020, NCEES (with SFPE's support) is planning to move the exam to be computer-based and potentially only permit portions of reference material to be available via PDFs.
These changes might not seem big on the surface, but with them the exam experience will change fairly dramatically - going from a personalized collection of customized notes, examples and self-made binders to more of a standardized approach similar to NICET exams.
Because of the uncertainty around the 2020 exam, I suspect there will be a good handful of PE candidates that if eligibile would opt to take the 2019 exam over being the "guinea-pig" on the new 2020 exam format. There's plenty more to be discussed and released by both NCEES and SFPE concerning the new computerized exam format, but it'll certainly be something I'll be tracking around here in the coming year.
MeyerFire in 2019
Thanks to the high level of interest and feedback for this site, everything is full-steam around here. The past year was phenomenal around here and I saw a major uptick in interest for the 2018 PE Prep Guide (two-thirds of examinees had it when they took the exam), the Weekly Exam Series, and the launch of the Toolkit.
In 2019 I hope to continue to improve upon the weekly blog series with highly-visual and hopefully helpful content, release a 2019 edition of the PE Prep Guide, and work towards a long-awaited fire protection reference guide - basically a book of helpful charts, graphs, and visuals for inspectors, designers, and engineers.
Why This Site Exists
This site was built to start the conversation.
I really would like to emphasize that I am not an end-all expert in the field. Much of what I've posted here as it relates to my own experience or industry guidance is already available.
What makes the emphasis of this site different is that it's all about bringing together experts in different fire protection factions to discuss and share best practices. It's about improving your workflow and your knowledge with resources and ideas, and giving a medium for you to share your expertise for other's gain as well.
If you're new to the blog or the website - welcome! We're well suited for a great year.
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Joseph Meyer, PE, is a Fire Protection Engineer in St. Louis, Missouri. See bio on About page.