Is Low-Piled and Miscellaneous Stoage the Same?

1/21/2022

I would like to differentiate between the density requirements for low piled and miscellaneous storage using NFPA 13-2019 Edition.

I have reviewed the the definition and literature in the code. That is all completely understandable.

Does miscellaneous storage meet or excteed the requirements for low-piled storage?

Based on the commodity, total storage area, total storage percentage, pile size dimensions, and storage spacing requirements - does all this factored in mean that the design density for the non-storage areas (like manufacturing or assembly) can be used under the miscellaneous storage area, instead of the densities provided in NFPA 13 Table 4.3.1.7.1?

For Table 4.3.1.7.1 - there is no mention of low piled storage in the title of the table - is this the table that would be used for the determining the densities for any low-piled storage areas? Is there not a separate table for low-piled storage?

I am likely overthinking things but some clarification or opinions would be appreciated.

Thanks in advance for the help.

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12 Comments

Pete H

1/21/2022 06:59:10 am

Not 100% the same. But they work out the same in most practice. From NFPA 13 (2013)

20.1.1: Miscellaneous and low-piled storage, meeting the criteria of Chapter 4, shall be protected in accordance with the relative occupancy hazard criteria reference in that section.

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4.3.1.4 Misc. Storage
4.3.1.4.1 - Misc. storage shall not constitute more than 10 percent of the building area or 4000 sq. ft of the sprinklered area, whichever is greater.
4.3.1.4.2 - Misc. storage shall not exceed 1000 sq ft in one pile or area
4.3.1.4.5 - Misc. storage shall be separated from other storage piles or areas by at least 25 ft.

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4.3.1.5 Low Piled Storage
4.3.1.5.1 - For storage of Class I through Class IV commodities of 12 ft or less in height that do not meet the definition of Misc. storage that is on solid shelf racks, in rack sprinklers shall be provided in accordance with 25.6.1, and ceiling sprinkler protection shall be provided in accordance with this chapter for the applicable occupancy hazard criteria.

4.3.1.5.2 For storage of Group A plastic commodities 5 ft or less in height that do not meet the definition of Miscellaneous Storage that is on solid shelf racks, in rack sprinklers shall be provided in accordance with 25.6.1, and ceiling sprinkler protection shall be provided in accordance with this chapter for the applicable occupancy hazard criteria.

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4.3.1.7 - Protection Criteria for Misc and Low-Piled Storage
4.3.1.7.1 - The protection criteria for misc and low-piled storage protected by ceiling sprinklers ONLY shall be selected from table 4.3.1.7.1 and Figure 19.3..3.1.1 ion accordance with the density/area method of 19.3.3.2.
4.3.1.7.1.1. - The protection criteria for rack storage of miscellaneous and low-piled storage with in-rack sprinklers shall be in accordance with 25.2.2
4.3.1.7.2 - Except as provided in 4.3.1.6.1 the maximum design area for misc and low-piled storage shall not exceed 3000 sq. ft.

4.3.1.8 - In Rack Sprinklers - Misc. and Low Piled storage per 4.3.1.5 through 4.3.1.7 that require in-rack sprinklers shall follow chapter 25 for their installation and design requirements.

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4.3.4 - Ordinary Hazard (Group 2) - The following shall be protected with OH2 Occupancy criteria in this standard:
1) Spaces with moderate to high quantity and combustibility of contents
2) Stockpiles of contents with moderate to high combustibility that do not exceed 12 ft.

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Yes, table 4.3.1.7.1 directs the discharge for misc. storage up to 12 feet in height: BUT you are directed (as per section 4.3.1.7) to use the same table for Low-Piled storage (which unlike misc. storage is not limited to a square footage of 4000/10% of the building, whichever is greater. And doesn't need to be in 1000 sq. ft. max stockpiles).

1/21/2022 06:59:49 am

Er. 2019 edition. Not 2013.My bad on that.

1/21/2022 07:06:22 am

The other fun thing to notice is that when you do meet those ever elusive requirements to be misc. storage and not low-piled storage, you aren't directed to use in-rack sprinklers on solid shelves as per 25.6.1 (but still might want to if you meet the +1 level of in-rack sprinkler note found in Table 4.3.1.7.1, in which case refer to 25.2.2.1 for design criteria.)

12/8/2023 06:47:15 pm

Pete if our storage is classified as Misc Storage do we not have to have in rack sprinklers on solid shelves?

Jesse

1/21/2022 08:25:11 am

Not 100% quite the same thing, but for the purposes of this, yes.

Misc. Storage is thought to be incidental to the greater occupancy for the most part - which is why there is the 4000 sq. ft / 10%. Think of it as a small manufacturing plant which would be OH2 that has a small raw materials / finished product storage area. Low piled doesn't have that incidental nature in it, and becomes "Storage" protected under 13s storage chapters once it hits the height threshold for each commodity.

Franck

1/21/2022 08:40:15 am

The main purpose is to be sure that if you are below the requirement of height for pile storage in the storage section chapter, you don't define a density that would be lower than for misc. storage.

Misc. storage was initially defined to cope with the little amount of storage within production areas. To be sure that if you have a design for OH gr 2 you can cope with some storage along the production lines.

Low pile storage is when you are below a certain height (12 ft) or when you apply the correction factor for storage height, to be sure that in no case you end up with a density lower than what would be required for misc. storage with the same height.

1/21/2022 08:42:01 am

The main difference with low pile storage and "normal" storage would be the selection of sprinklers (temperature rating) and installation of sprinklers (spacing, coverage area / sprinkler...), as you can follow the rules for OH Gr 2 and not the one for storage.

Jay

1/21/2022 09:31:10 am

The table you're referring to is only applicable to storage that meets the definition of miscellaneous storage.
The most common situation you'll come across that requires different densities between miscellaneous and low-piled storage is the storage of group A plastics. If it is low-piled storage of group A plastics greater than 5ft in height, you cannot use Table 4.3.1.7.1.
2016 and earlier editions spelled this out clearly in the beginning of chapters 15 and 17, but now not so much.
See Table 21.3.1, Table 21.3.3, 21.5.2, Table 21.5.1.1, and Table 21.5.3.
For example, if you have 10ft rack storage of exposed/nonexpanded group A plastic with a ceiling of 20 ft and is defined as miscellaneous storage the design is EH2 or .4/2500.
The same storage arrangement defined as low-piled has a design of .8/2500 (Table 21.5.3).

Todd B

1/21/2022 12:49:44 pm

Thank you everyone for your comments and help

Pete D

1/22/2022 10:20:40 pm

Be warned. In the definition chapter, 3, there is a definition of miscellaneous storage and another definition of miscellaneous tire storage, and they're different.

Todd Wyatt

1/24/2022 08:47:23 am

The 2021 IBC (the scoping Code for automatic sprinkler systems) references the 2021 IFC regarding "high-piled stock or rack storage" per 413.1 General.(https://codes.iccsafe.org/content/IBC2021P1/chapter-4-special-detailed-requirements-based-on-occupancy-and-use#IBC2021P1_Ch04_Sec413.1)

2021 IFC Ch 32 High-Piled Combustible Storage outlines the requirements for automatic sprinkler systems for both high-piled and rack systems and references the NFPA 13 in (11) instances in this chapter.

OSMAN OMRAN OSMAN

7/23/2023 03:52:04 pm

I am thinking that there are a contradiction between:

4.3.1.4.1 Miscellaneous storage shall not constitute more than 10 percent of the building area
or 4000 ft2 (370 m2) of the sprinklered area, whichever is greater.

4.3.1.7.2 Except as provided in 4.3.1.6.1, the maximum design area for miscellaneous and
low-piled storage shall not exceed 3000 ft2 (279 m2).

Could you please explain it to me.

Thank you

Is Low-Piled and Miscellaneous Stoage the Same?

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