ESFR Advice for Architects + Structural Engineers?

11/14/2023

Question submitted from Joe Meyer as pertains to a whitepaper in the works for ESFR systems:

Many of us have come to the realization that with ESFR systems, the "building is designed around the sprinkler." That adage seems to be more and more true with each ESFR system.

What advice would you offer to architects and structural engineers on the "best ways" to design around ESFR; making the building more ESFR-friendly?

Thanks in advance!

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14 Comments

Dan Wilder

11/14/2023 07:04:13 am

Of the top of my head....

Open web trusses - 8' on center
Provide an allowance for the first to third truss on each side of the warehouse for a heavier load (mains to avoid trapeze)
Allow adjustment for any roof penetrations and horizontal MEP trades to be centered between branch lines/sprinklers
When using BAF, prepare to have those locations adjustable as well

Pete H

11/14/2023 07:12:47 am

Advice for NFPA 13 design only, not FM:

24'-0" bays are ideal in buildings under 30 feet.

30'-0" bays are ideal in buildings over 30 feet.

Expect to be able to hang large sprinkler feed mains (6-8 inch) as well as floater mains and have a gridded branch line system.

Heat the place, I can't do a grid on a dry system.

Open ceilings are better.

I need 36" clear from deflector to top of storage. And to expect my deflector 6-12 inches below deck. (yeah, it's more specific based on upright or pendent, but these numbers work for both). So ideally have storage cease 4'-0" below deck.

Expect a pump if your storage is high enough.

Avoid group a plastics in buildings over 40'-0" for deck height, as those are likely to still require in-racks.

Pete H

11/14/2023 08:02:34 am

Oh and no ceilings with a slope greater than 2 in 12. Flat ceilings as much as possible.

Michelle L

11/14/2023 08:35:39 am

If a fire pump is necessary, provide a large enough room for it and all required equipment. I ask for 20 x 20, though I understand that's not always possible.

Pete D

11/14/2023 08:52:00 am

A couple of things come to mind. 1st. The architect must be cognizant that his warehouse TOS dimension is limited in height, if he wants to design a building protected by ESFR. There are some specially listed sprinklers that raise the roof (so to speak), but outside of those raised limits the only other options are to protect with a different strategy or install a ceiling.
It's important to let the architect know on the front end that the MEP design is contingent on the ESFR layout. Just the head spot and mains, not the completed shop drawings. In this regard either the FPE with need to provide a preliminary head spot, or the sprinkler contractor will need a design-build contract negotiated. I use a drawing detail that depicts both NFPA ESFR spacing off obstructions and the grouped obstruction rules from FM. Layout technician requires a steel erection plan with details of the girders to pick a pass-through point (elevation and off column) for feed and float mains. If they deviate from the plan, the will need to pay for 4 90s to offset beneath the girders at each intersection. Make the pump room big enough for a fire pump. Ask the FPE how much space is needed. If the site includes back-up generator power, coordinate a back-up circuit for the jockey pump. Obtain power reliability statistics from the purveyor.

Jesse

11/14/2023 09:43:23 am

Great post Joe!

I'd say, we need:

1) open web trusses.
2) Keep the roof flat. Don't exceed 2:12
3) Give me a big enough room for my pump and all of the risers!
4) Make sure you have 3-Ph electrical for the pump
5) Depending on the applicable version of 13, avoid expanded Group A
6) Let me know now the extent of HVLS fans

Casey Milhorn

11/14/2023 09:50:39 am

All great comments. There is a lot going on right now around the K28 heads from Reliable and the K34 from Tyco. They have some very specialized listings that will allow for higher buildings/storage, tighter aisles, tighter flue spaces, that all could be very very attractive to the end user and maximize their storage space. This is HUGE to them. Design the building around the tenant's needs, but incorporate a specific ESFR head up front.

Involve a design build fire protection contractor day 1 if possible.

Find out if there is a specific insurance carrier involved day 1. FM Global, etc.

Get a NFPA 13 owners certificate filled out from the building owner, and tenant if applicable, day 1.

As Dan said, either 5' on center or 8' on center. Avoid weird joist spacing, and/or inconsistent spacing. Avoid structural bracing when possible.

Brian Cockburn

11/14/2023 09:55:10 am

Make sure seismic requirements are thought through if you're in an earthquake zone. Early coordination between the Fire Protection and Structural Engineer will pay off here.

Cesar Reyna

11/14/2023 11:36:45 am

Ensure that the ceiling height/roof height based on the ESFR design criteria is closely coordinated during construction and well documented on the Architectural sections.

An ESFR design for a 30'-0" ceiling height/roof would jump up to the next design criteria if the field measurement comes out higher...

Has anyone discovered this during a construction administration visit? I had a warehouse exceed the 30'-0" height by 6" to 8" about 15-ft on either side of the peak...how did you guys handle this?

11/14/2023 11:49:46 am

1) NFPA 13, 2022 §14.2.11.3.2 (1) "Where the bottom cord is 6" or less in width, the sprinkler shall be located a minimum of 6 in. horizontally from the nearest edge of the bottom chord."
2) For buildings with 30'-0 bays space bar joists every 5'-0 for 10'-0 sprinkler spacing. For buildings with 40'-0 bays space bar joists every 5'-0 for 10'-0 sprinkler spacing or 8'-0 for 8'-0 sprinkler spacing.
3) ESFR system demands change substantially when the roof heights exceed 30'-0 (especially in NFPA 13, 2022 edition)
4) Hang lights directly below bar joists since ESFR sprinklers avoid bar joists.
5) Keep HVAC under 24" wide as much as possible to avoid additional protection below.
6) Make sure roof pitch doesn't exceed 2:12
7) Space HVLS fans after sprinkler layout is determined to make sure the fans are between 4 sprinklers.
8) Make sure to flow your system demand during flow testing (or as close as possible) to make sure you don't need a supplemental water tank.
9) Don't forget to check fire flow requirements if you have fire hydrants around the building.
10) Specify the level of ESFR protection and understand what commodity classification the fire sprinkler system will be providing

Rick Rantamaki link

11/14/2023 01:03:59 pm

If possible, try to locate the water entry/fire pump room as close to the ESFR hazard as possible (or vice versa) - to minimize large pipe runs.

Anthony

11/15/2023 12:47:42 pm

Architects should not specify ESFR, only the specific hazard to be protected. they typically do because with ESFR then they do not need smoke and heat venting. Now we have multiple options for this protection scheme not just ESFR like CMSA and EC25.
they really box us in when they specify ESFR.

11/16/2023 01:42:56 pm

1. Coordinate RTU locations around ESFR sprinklers
2. Solid steel reinforcement for RTUs also need to be coordinated
3. Joist fabrication should not start before sprinkler contractor has had a chance to review. Coordinate bridging locations with ESFR
4. If project is phased - any demising full height walls need to be coordinated.
5. No solid shelves! (there are some schemes around this)
6. I've had a project where lights were spec'd as 48" x 26" - not cool!
7. Explore other options like EC25s. ESFR is not a catch-all

sean

11/16/2023 06:45:12 pm

clear understanding of the proposed storage...

ESFR Advice for Architects + Structural Engineers?

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