Storage Height/Roof with Pallet Storage Above?

9/11/2023

Regards from Norway -

Modern storage and picking racks often combine small units, both bins and cartons, in flow-through for picking in the lower part, and ordinary pallet storage above. I believe this is common worldwide, but few sprinkler standards, if any, provide guidelines on vital parameters.

Case: We're dealing with ordinary open pallet racks. The commodity class is up to 3 (possibly 4). The picking height is up to 7-ft (2.0 m) based on mini wheel flow-throughs. Above that, there are 4-5 standard pallets with total net storage heights of 26-ft (8.0 m) in a building with a 39-ft (12 m) ceiling height.

It seems feasible to protect the pallets with ceiling-only sprinklers. However, there's no vertical alignment with any transverse flue spaces in the picking part. It seems logical to install a horizontal fire barrier above this area. How should we protect the lower part of the racks?

Should the ceiling sprinkler water demand be based on 26-ft (8 m) storage at a 39-ft (12 m) ceiling height, or 26-ft (8 m) at a 33-ft (10 m) ceiling height, measured from the top of the in-racks for the picking area?

I hope someone has a view on this matter. A not-yet-finalized version of EN 12845-1 has some parameters for systematically constructed automatic small unit storage, but my actual case is for manual operation and is not specifically systematic for the small units area in only a couple of the racks.

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5 Comments

Pete H

9/11/2023 06:48:06 am

I'd go with 26' for the 39' ceiling heights.

If the pallets were on top of a mezzanine where the mezzanine created a separate floor assembly, that'd be one thing. But they're just on top of the racks. So the floor the ceiling height is taken from is going to be the floor, not the top of racks.

In my opinion.

9/11/2023 08:22:18 am

Looking at this closer....

I also don't know how the ceiling only changes 3'-0" when the top of rack storage is 7'-0" in the description as the picking up height. Seems like those numbers shouldn't work.

Chances are any ceiling only protections scheme that works for 26'-0" of pallet storage will also work for 7'-0" of rack storage.

So protect 26'-0" of high piled pallet storage for the commodity with a ceiling only protection scheme as expected.

Then check chapter 13 and make sure that protection is above what is required for ceiling only protection of rack storage up to 7'-0" for that commodity (I see no world where this is not true.)

As long your ceiling only system can protect both, it can protect both.

Jesse

9/11/2023 08:40:30 am

The total aggregate height of storage - from floor to top of storage including the picking shelves.

And note; top of storage, not top of rack. The storage may exceed the rack height.

Casey Milhorn

9/11/2023 09:30:36 am

My concern would be the statement that the flue spaces do not line up in the pick module area below the rack storage. If the pick module storage arrangement creates a horizontal barrier similar to a solid shelf, that could be an issue. A fire could grow and spread horizontally through the pick mods and also be shielded from the system above.

Franck

9/13/2023 09:20:07 am

Yes
Same issue as it would be with solid shelves.
Some longitudinal and transversal space need to be provided (especially the transversal, longitudinal is optional, eventhough better if provided, as the height of storage remains below 25 ft) to enable the fire to reach the ceiling along the racks and water to go down to the ground inside.

Storage Height/Roof with Pallet Storage Above?

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