We have a project where the tenant intends to store Class I to Class III commodities that have a typical footprint of 12’ x 3.5’ (42 SF) on open-wire mesh racking.
Between the Definition 3.3.172 (NFPA 13-2019) Rack Shelf Area which specifically calls out “by the placement of loads” and the definition “Open Rack” (3.3.140) it appears that this condition has to be viewed an Solid Rack and would require In-Rack sprinklers no matter what roof level system (CMDA, ESFR, K-25) is installed or the Commodity Class stored. I know there are some special designs related to “big box retail” stores (Mercantile) for this, but our application is Warehouse (Storage). There are also additional conditions if the footprint is greater than 64 SF. Is there a way to read the above definitions that would not require in-rack sprinklers when Loads with a footprint over 20 SF and less than 64 SF are placed on otherwise Open Rack? Requiring in-rack sprinklers is a potentially major expense for an owner with 75+ operable facilities like this. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
5 Comments
Franck
5/27/2021 09:32:55 am
I am afraid you're right and it may cost a lot for your owner with his 75+ locations...
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Robert Anderson
5/27/2021 07:18:42 pm
I agree with everything you said related to horizontal fire spread. The concept of Placement of Loads creating solid shelving has been in the Code for several years now, but I visit so many facilities that have racks with oversized pallets, door slabs, lumber, pipe, sofas, hand stacked loads without transverse flues, etc. where this issue has not been address. If there was any gray area in the language it appears NFPA doubled down on the concept in the 2019 Code.
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Franck
5/28/2021 02:36:55 am
Note that for solid shelves between 20 sq ft and 64 sq ft – as measured between aisles and flue spaces – in rack sprinklers must be added, but not necessarily below every shelf (depending on arrangement).
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franck
5/27/2021 10:09:48 am
Just to add a personnal view (to be discussed with the AHJ / Insurance company) : maybe the class I commodity storage is not much of an issue, in particular if you design your entire storage area for a class III commodity storage, as you will have safety margin from the class III commodity design to cope with the adverse conditions on your class I commodity storage.
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Franck
5/28/2021 02:35:37 am
Some additional information:
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