S-1; Providing protection for high hazard storage

[Sdpaddler50]

S-1, Type III-N, rack storage Class I-IV, but also fairly large amount of Group A, unexpanded plastics.

-Sprinkler protection (ceiling only) adequate for the Class I-IV per engineering analysis I did.

-Sprinkler protection is not adequate for the plastics – shocker. They will either need to reinforce the ceiling, or add in-rack sprinklers. This would then be a separate area, and controls put in place to store the nasty plastics here only. I know this has its own inherent challenges, but I believe this operator has the ability to manage it because these are distinct products lines.

Per Cal Fire Code 2010

2304.2 Designation based on engineering analysis. The designation of a high-piled combustible storage area, or portion thereof, is allowed to be based on a lower hazard class than that of the highest class of commodity stored when a limited quantity of the higher hazard commodity has been demonstrated by engineering analysis to be adequately protected by the automatic sprinkler system provided. The engineering analysis shall consider the ability of the sprinkler system to deliver the higher density required by the higher hazard commodity. The higher density shall be based on the actual storage height of the pile or rack and the minimum allowable design area for sprinkler operation as set forth in the density/area figures provided in NFPA 13. The contiguous area occupied by the higher hazard commodity shall not exceed 120 square feet (11 m2) and additional areas of higher hazard commodity shall be separated from other such areas by 25 feet (7620 mm) or more. The sprinkler system shall be capable of delivering the higher density over a minimum area of 900 square feet (84 m2) for wet pipe systems and 1,200 square feet (111 m2) for dry pipe systems. The shape of the design area shall be in accordance with Section 903.

But, I, and client don’t want to be limited to storing the high hazard plastics to 120 sq ft piles. They have about 5,000 sq ft of plastics in racks to 18 ft high so this is not practical.

NFPA 13, 2013:

5.6.1.2.4 Mixed Commodity Segregation. The protection requirements for the lower commodity class shall be permitted to be utilized in the area of lower commodity class, where the higher hazard material is confined to a designated area and the area is protected to the higher hazard in accordance with the requirements of this standard.

I would assert that if the protection is improved for the plastics (in-racks for example) then we have succeeded in providing adequate protection per NFPA 13. From a practical sense, what is limiting the pile sizes, or providing 1 hour fire walls in between the lower hazard, and high hazard storage going to do, which is now adequately protected?

IE, my assertion is that the sprinkler system will control a fire involving the high hazard, so the provision of fire walls, and/or limiting pile sizes is not needed. But, when I go back to the fire codes, it is telling me otherwise.

For example – what if a brand new building goes up across the street, and they store group A plastic exclusively. As long as the sprinkler system is designed to protect the storage per 13, we don’t need any fire barrier walls there.

Has anyone been successful in taking this approach with the ahj to omit fire barrier walls, or pile size limiations? Any other ideas, or options are appreciated.

 

[cdafd]

Well if you design the entire system for the plastic storage, that should allow the client to do what they want??

Am I missing something ??

Like your example of building a new plastic storage building

 

[Sdpaddler50]

"Well if you design the entire system for the plastic storage, that should allow the client to do what they want?"

It's about economics, and, the fact that we dont need additional protection in the entire warehouse, just the plastics. To illustrate:

The cost to provide the needed protection for the plastics (in-rack sprinklers) is about $15K.

The cost to provide in-rack sprinklers throughout the entire building is about $200K.

 

[cdafd]

Got list along the way

"""But, I, and client don’t want to be limited to storing the high hazard plastics to 120 sq ft piles. They have about 5,000 sq ft of plastics in racks to 18 ft high so this is not practical.""""

1. You are intending to store the 5000 Sw ft plastic by themselves ????


Appears you can do it with a one hour wall, is the owner willing to do that??

 

[Sdpaddler50]

My contention is we shouldnt have to put up walls, limit pile size, etc based on what i initially wrote. Anyone else willing to chime in here?

 

[cdafd]

Sorry should have said one hour wall but not have to limit like size

If you look at the un amended IFC it requires separation or other

Have you tried calling the state fire marshal office for interpretation ???

 

[stookeyfpe]

Spaddler50,

I would go with a 3rd option and that is IFC Section 2306.3.2.2 and be done with it. I understand what NFPA 13 allows, but I've played the Where's Waldo version of finding Group A plastics for so many years that I won't accept it in my jurisdiction, unless they offer a reliable method of segregation. The problem with applying NFPA 13 Sec. 5.6.1.2.4 is that I know of some jurisdictions (not mine) that makes one retrofit S&H vents because the hazard has supposedly increased. My response to that logic is that the hazard was probably always there - neither the owner, tenant or in many case the fire official, recognized the problem.

StookeyFPE

 

[Sdpaddler50]

Stookey - thanks. I understand what you are saying in regards to the wheres waldo game - i have been through that one myself a few times. The ahj's in my area will ask for the vent increase as well. On a related subject, one of my pet peeves is allowing spec bldgs to be designed for Class IV (or less) in the first place. It's rare to see a true class IV warehouse anymore, in our world comprised of plastics. I think ahj's should ask for Group A unexpanded protection for new construction and it would save us all alot of headaches in the future. Ok, i will get off my soap box now.

 

[stookeyfpe]

Spaddler

With CMSA being required for any NFPA 13 system with a discharge density > 0.34 GPM/Ft.^2, we out here in my little Texas town are in the process of revising our policy on speculation warehouses to require the sprinkler design be based on:

A) Cartoned, Unexpanded Group A plastic
B) Wooden or UL 2368 listed plastic pallets
C) Minimum 36 inch commodity to sprinkler deflector clearance
D) Wet-pipe system

One month ago I did a third party plan review for a jurisdiction in Missouri Valley that accepted a OH-G2 design for a 89,400 Ft.^2 Type IIB Group S-1 with a BOS dimension of 31-5. That's what they required and that's all they wanted.

 

[Sdpaddler50]

Good to hear Stookeyfpe. We have alot of big boxes in my area, and many of the new ones are done ESFR, or at least piped for "ESFR Ready". I still see the lower densities however in the smaller warehouses. That ahj should read your book, and the associated pitfalls with inadequate sprinkler densities and high pile storage.

 

[stookeyfpe]

Regarding ESFR and big boxes: It's the hazmats that make me very, very cautious.