Speculative warehouse??

[Oremus]

I'm designing a sprinkler system for a little 7,000 sq. ft. warehouse with about 1/4 of it being group 'b' occupancy and the actual warehouse being S-1 occupancy. This is split down the middle to accommodate two tenants. The fire sprinkler contractor estimated this project based upon ordinary group II water densities but I don't think that's appropriate given the speculative nature of who and what might go in these spaces. This is a simple metal warehouse building and the highest point is at about 25 ft. I would say max storage you could possibly stack to would be about 20 ft. I'm thinking if they don't have a specific occupant or are not going to limit what is stored and how high then this should probably fall under the city's 'speculative warehouse' ruling which requires a .64 gpm / 2000 sq. ft. density which totally blows away their bid price and may even require a fire pump. Am I going overboard or should we just stick to the ordinary group II and state on plans and to owner that this only allows storage to 12 ft of up to class IV commodity with no group 'A' plastics etc...

Does anyone have any advice on how to approach this?

THanks,

Oremus

 

[TravisMack]

I have seen these go both ways. The safest is to go with the spec warehouse design. However, if the owner is willing to limit his tenants to storage that would satisfy the 0.20 gpm / sq ft then you may be OK. I would at least do 0.20 gpm / 2000 sq ft, possibly even 0.24 gpm / sq ft over 2000. That way, you get 130 sq ft spacing, so you aren't increasing number of heads or lines. Also, you could get Class III commodity in rack to 16'.

It all depends on what the building owner is willing to work with. Does he want an inexpensive system and limit tenants, or does he want a more expensive system and open up to a broader range of tenants? With such a small storage space, it may be conceivable to limit to Class III to 16' in rack, or Class IV solid pile to 20'.

So, as you can see, you may be able to stay within the contractor's budget and still provide some greater level of protection than just 0.20 / 1500 sq ft.

Travis Mack
MFP Design, LLC

 

[SprinklerDesigner2]

Forget what town it was in but one had a warehouse ordinance where all warehouses had to be designed for a Class IV commondity to 20'. All warehoues were required to have a red stripe mainted all around the perimeter at 20' above floor level. Inspectors would climb a ladder to 20' expecting not to see the red stripe blocked.

Town had a good water supply so pumps weren't involved.

.64 sounds a little restrictive to say the least.

 

[Oremus]

Travis,

I had actually started doing some prelim source calcs using pipe sizes which you would typically see in an OH2 situation to see what max density they could possibly get away with without shrinking anyone's wallet. I came up with around a .30 / 2,000 sq. ft. so I'll cross reference this and see what exactly they can get away with as an option.

Thanks for your input!

 

[LCREP]

"This is a simple metal warehouse building and the highest point is at about 25 ft. I would say max storage you could possibly stack to would be about 20 ft."


I see this everyday, what makes you think the building owner is going to limit the height of storage of the tenant? Who is going to rent a bld that u have room to store to 20' and only let them store 5-12' depending on the commodity? No ONE!! They will store as high as they can go. Look at NFPA 13, 02, table 12.1.10.1.1 on pg 106, .20/1500 does not do much for u.

I like what Mack said, not perfect, but better then .20/1500. I think I would go with 100 sq. ft. spacing and a large safety cushion for future upgrade.

I like that .64/2000 who required that?? Someone did some homework!




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Fire Sprinklers Save Firefighters’ Lives Too!

 

[Oremus]

SprinklerDesigner,

I think .64 is probably overkill given the size of this thing and the city's water supply. The sprinkler system would probably cost more than the building if a fire pump had to be installed. Calculating 2,000 sq. ft. is about 80% of the whole warehouse area. I've never known of anyone who had to use the default .64 gpm / 2000 sq. ft. since most take one look it and start writing out a list of limitations for their clients

 

[cdafd]

"this should probably fall under the city's 'speculative warehouse' ruling which requires a .64 gpm / 2000 sq. ft"

we have a spec warehouse rulle but not this requirement,

But no matter what youdecide on if the ahj wants it than that is who you have to make happy!!!!!!!!!!


have you asked the ahj??????????

 

[DonPhillips]

It appears you are being prudent and advising your client on the "cost" of not knowing what the future will bring. You may want to price it both for what you know today, and what may likely happen in the future, so that the client can decide if rolling the dice to save money today is worth it.

Don Phillips

http://worthingtonengineering.com

 

[firepe]

Just a couple of things to add to the discussion...

you said..."Am I going overboard or should we just stick to the ordinary group II and state on plans and to owner that this only allows storage to 12 ft of up to class IV commodity with no group 'A' plastics etc..."

In the general storage rules in NFPA 13 for Class IV Commodities stored in racks, you CANNOT go to 12-ft. high, you are limited to only 10-ft high on Class IV rack storage.

In addition, if higher storage heights are indeed needed later, and all you have is OH-2, you will have to prove a 2000-sq.ft. area instead of 1500-sq.ft. area, once you cross the occupancy class threshold into a storage occupancy, and you could always add in-racks as an option instead of increasing the ceiling density.

In order to gain some flexibility, I would also recommend a 0.249/2000 density, which maximizes the 130-sq.ft. per head usage, utilizes the 2000-sq.ft. remote area minimum required for storage occupancies, and allows some flexibility in solid pile storage as well. It would also be wise to include 500-gpm hose instead of 250-gpm, just to make sure it is covered.

Just my 2 cents.

 

[Oremus]

Firepe wrote, "...Just my 2 cents."

Your two cents is in the piggy bank - thanks for all the input!