ESFR Allowed On Return-Bend?

1/26/2022

Are there any restrictions (by code) for using a return bend on an ESFR pendent sprinkler?

We have structure in both directions, with 21-inch deep beams which requires the pipe be installed underneath the beams.

Thanks in advance!

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

9 Comments

Alex

1/26/2022 07:02:59 am

Hi,

Return bends are a type of arm-over where it is piped from the top of the branch line/main (rather than from the side or bottom). This helps avoid sediment and mineral accumulation within the pipe.

Return bends are not required by code for sprinklers with a K-factor larger than 11.2 (NFPA 13 (2013) 8.15.19.5). The thought here is that a larger orifice will allow sediment to pass and not block waterflow.

I believe you are simply wondering if you can use an arm-over to protect underneath an obstruction. If that's the case, yes. Although, as always, you need to make sure the system works hydraulically. You still want to ensure the sprinkler contractor installs the sprinkler per the manufacture guidelines (sprinkler arms parallel with arm over, XYZ).

Thanks,
Alex

Anthony

1/26/2022 08:01:54 am

As Alex said there no code that says you can't.

Some options:

Can you run the pipe in parallel to the beams?

Maybe do several small (2 heads per side) tree system with lines up in the beam pocket?

I hoping its just a few bays or that's going to be an expensive install.

The return bends are going to kill your calcs.

Best of luck!

Jesse

1/26/2022 08:08:03 am

The purpose of the return bend is typically with particulate matter occluding smaller orifice sprinklers. Since you're dealing with ESFR that isn't an issue, and there is nothing that prevents you from doing this. However, it does create some hydraulic challenges you need to deal with on the engineering side.

Emil Ohler

1/26/2022 08:27:38 am

Just a thought, if your piping is installed below the beams could you install the piping low enough to allow upright ESFR's

JASON YEAGY

1/26/2022 08:33:35 am

I'm assuming your using return bends to attain a desired deflector distance from the deck. My understanding is that as long as the added pipe and fittings are included in the hyd calcs, you'd be able to install ESFR on a return bend....that, or use upright ESFR on sprig.

Franck

1/26/2022 09:11:38 am

In addition to the comments above, I have already seen such installations in the past.
One of them was related to a retrofit of an existing system, where the initial sprinklers were installed upright and they changed them with pendent ESFR.
As long as the hydraulic calculation with the extra length for fittings works, there is no reason against.

Jack G

1/26/2022 09:54:05 am

In the past , Walmarts in particular, when arming to an ESFR under units our in pockets with piping like a return bend for deflector distance compliance, I ve found “ you can’t do it with 1 inch “. Run a calc for the flow and pressure you need. Probably 1.5 inch minimum.

Brian Gerdwagen FPE

1/26/2022 10:20:10 am

In addition to the above guidance, make sure that you do not create an obstruction to the sprinkler of your own branch line piping. I have used return bends on ESFR sprinklers many times in existing construction, but it isn't ever easy.

danefre

1/27/2022 09:52:15 am

We do it all the time. Branchlines tight to the beam and offset a minimum 1'-2" horizontally away from the ESFR pendent since the branchline is an obstruction. The pendents are installed on a return bend and end-of-line fitting. If you nail the measurements you don't have to hang the armover but you probably should.

Requires additional calcs.

Heads can't be closer than 8'-0 regardless of beam obstructions for most jurisdictions.

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 © 2016-2024 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.

ESFR Allowed On Return-Bend?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES