Use Different Criteria for Low End of Sloped Roof?

8/6/2025

I have a project with a 40,000 sf refrigerated storage area with an exposed metal deck roof with steel joists. Roof is sloped; the low end is 29-ft floor to deck and the high end is 31-ft 8-in.

Can I use the sprinkler criteria of 30-ft max ceiling height for storage areas of this space that are below the roof, where it is 30 ft or less, and use different sprinkler criteria where the roof exceeds 30 ft?

More specifically, do I need to use the maximum roof height for the sprinkler criteria of the entire space?

My issue is that there is rack storage and palletized storage, and FMDS 8-9 does not have a ceiling-only solution for palletized storage with a ceiling height greater than 30 ft. Any insight is appreciated, thanks.

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

3 Comments

Dan Wilder

8/6/2025 07:57:35 am

Yep -

13-19 Ed - 20.6.2.5
Annex has a nice picture of intent for these sections.

13-19 Ed - 20.10.1

You'll need to use the 15' extension of the higher hazard into the lower hazard space starting at the point the roof deck is at that 30' point. Or use a draft curtain or barrier but also need to comply with the 2' minimum on each side separation requirements

I can't speak to FM guidelines if that is allowed, been a minute since I've had to dig that deep into 8-9.

Glenn Berger

8/6/2025 08:16:46 am

1) 29 foot roof height - The reference that Dan provides has additional criteria that must be met before you can utilized the decrease design parameters for a lower roof elevation. If you can comply with all of the regulations that go for it.

For low roof height of 29 feet and a high roof height of 32 feet, I would use one design criteria across the entire area.

2) Need to check with the latest FM guidelines, typically I just get a ceiling installed at the 30 foot level for compliance with the published standards.

Anthony

8/8/2025 09:05:02 am

You could with a baffle, separate the 2 areas FM has language on baffel construction.

I'm more curious about the non ceiling only protection? Do you have horizontal barriers in your racks? All the charts in FM 8-9 data sheets go up to 40 ft with K25.2 sprinkles.

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.

Use Different Criteria for Low End of Sloped Roof?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES