Best Sprinkler Layout for Long Structural Spans?

3/27/2026

I have a curved roof structure over a waterpark that has a top of steel of 37'-6" on the ends and 59'-8" at the peak.

Portions of the roof are also retractable, leaving little to no steel to hang from. In these areas where the roof retracts, joist girders are 16'-8" apart east to west, and we have purlins running north to south that are over 18' apart.

We were looking at potentially using EC heads, but have a pretty good roof pitch, or using standard heads and spacing couplings between girders; however, hangers would be 16ft apart.

How might you attack this, given the wide spans of the joist girders in one direction and purlins in the other?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

6 Comments

Dan Wilder

3/27/2026 07:45:57 am

Just spit balling this morning...

This would be a great question for an FPE to design performance-based design criterion. In addition, working directly with the structural engineers to resolve the available hanging methods with the proposed structure.

On the surface, what is the actual fuel load, Si this a large pool with slides in the high areas, what are the egress options, are there other systems in place like smoke control, how are they approaching detection and notification?

Would/could alternative means like water monitor nozzles/UVIR detection for the large open areas be a better approach while protecting the base structure pathways (stairs to rides, tunnels, covered paths, smaller ancillary buildings with the main structure) with the traditional fire sprinkler approach?

Could the stationary horizontal roof structure between the major structural elements hold the piping with modification for hanging means (welded tabs, penetrations through the deck, modified support steel in the area of hanging points - all require structural design and sign off). The areas of the retractable roof should not receive protection as the logistics alone to account for the movement and clearances would be well beyond practical.

Zack Hinson

3/27/2026 08:18:16 am

There are a few exceptions to break the 15'-0 hanger spacing rule in FM 2-0 that you could consider. You would need to discuss it with the AHJ and get their approval of course. I have only ever used it once.

Jesse

3/27/2026 09:09:56 am

My first reaction is that I'm glad this your project, and not my project.

I think Extended Coverage sprinklers are the right track. But the retractable roof function complicates this.

I would definitely get the with structural engineer about how / where to hang from

Rob

3/27/2026 03:23:01 pm

Standard heads ...... and trapeze everything.

Jack G

3/28/2026 11:29:59 am

For tent structures at Great Adventure, an FM global insured,
We ( and Fm ) ran lines up the support trusses elbowing back a forth to each side of it to angle/ mimic the curve.
We d put EC sidewalls with baffles on them / back to back, to spray the 16-8 span. This way ( 2 directions ) you skip a truss.

Rocket

3/29/2026 11:55:49 am

Start by classifying the commodity.

Water parks typically have areas from LH to OH2. Mixing commodities in one fire compartment may require OH2 or even EH, especially if chemicals are involved—double check with the operator, as substances like Muriatic Acid and Sodium Hypochlorite are generally low hazard for fire.

Refer to NFPA 13 table 19.2.3.2.5 for ceiling heights over 30 ft, which imposes strict requirements for EC sprinklers. If your jurisdiction uses an older edition of NFPA 13, you might avoid this table, but updates have valid reasons.

Are FM Global datasheets acceptable for A-3 occupancy by your AHJ instead of NFPA 13?
DOW engineers typically do not accept them,except in Storage occupancies.

Leave a Reply.

Home
Our Cause

The Blog
The Forum

PE Exam Prep
The Toolkit
MeyerFire University

Pricing
Login
Support
Contact Us

MeyerFire.com is a startup community built to help fire protection professionals shine.
Our goal is to improve fire protection practices worldwide. We promote the industry by creating helpful tools and resources, and by bringing together industry professionals to share their expertise.

MeyerFire, LLC is a NICET Recognized Training Provider and International Code Council Preferred Education Provider.
All text, images, and media Copyright © 2016-2025 MeyerFire, LLC

We respect your privacy and personal data. See our Privacy Policy and Terms of Service. The views, opinions, and information found on this site represent solely the author and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence.

Discussions are solely for the purpose of peer review and the exchange of ideas. All comments are reviewed. Comments which do not contribute, are not relevant, are spam, or are disrespectful in nature may be removed. Information presented and opinions expressed should not be relied upon as a replacement for consulting services. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a small commission for orders placed elsewhere.

Best Sprinkler Layout for Long Structural Spans?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES