Storage by NFPA 13 in Denmark?

[Bagge]

Hi,
I'm a sprinkler Engineer from Denmark, and are new at this forum. Very interresting site, I must add.
So can't help wondering whether or not you guys maybe can help me out.
In Denmark we are primary using the CEA rules, but are allowed to use the NFPA 13 rules though. I'm considering to do this, because of the larger selection of sprinkler types allowed in the NFPA 13.
I have a specific project design I have an question about. I know that it is a time-consuming post and reply, and I totally understand, if you do not have the time for a reply. But I will try anyway, and just hope somebody can find the time.
Data:
It is a lumberyard. Double Rack combined with solid Piled Storage (see atachements), max. storage height 20 feet. Max. ceiling height 25 feet. No shelves. Aisles bigger than 1.2 m. Dry System (!) No in-rack sprinklers.

If I use the CEA rules my max. Storage Height is only 11 feet (in Denmark a lumberyard would be classified as Commodity III).
But does the NFPA 13 give me better design criteria option (other types of sprinklers)? I have attached some pictures that shows the method of storage. Would this also be classified as commodity III by the NFPA 13? Let me hear if there are lack of information in the post for a good reply.
(please forgive my bad English writing)

 

[stookeyfpe]

Welcome to the forum. It’s interesting to help a fellow engineer who is “across the pond.”

NFPA 13 has criteria for the storage conditions you described and provided in your photograph. While I have never read or seen the CEU rules, the Class III commodity classification is somewhat correct. However, the photograph indicates some of the wood is wrapped in plastic film. This requires under NFPA 13 that the stored commodity be further classified as an encapsulated commodity. Based on the orientation of the stored products and the photo I would classify it as a Class III encapsulated commodity.

The indicated height of storage is 6 meters or about 20 feet using US measurement units. Your aisle dimensions are 1.2M or about 3.94 feet. The building is not heated so a dry pipe automatic sprinkler is required. For solid pile storage at this height, NFPA 13 offers no guidance. NFPA 13 contains no data for solid pile storage heights of encapsulated commodities > 15 feet or 4.6 meters. This is based on the lack of fire testing data for this type of storage above the indicated height. I would recommend that your client change the storage arrangement from a solid pile storage arrangement to rack storage so that more design options are available for the protection of the stored commodity.

If your client converts the storage to double row racks, as you stated in your original posting, NFPA 13 contains a number of options for the protection of the Class III encapsulated commodities with aisle dimensions of 1.2M. However, a cursory review of NFPA 13, Table 12.3.2.1.2 requires the installation of at least one level of in-rack sprinklers and the use of control mode-specific application sprinklers with a minimum orifice diameter equivalent to K=11.2 or larger. The fact that a dry pipe system is required will add additional complications but it can be protected provided the correct sprinklers are selected.

While not mentioned in your original post, I see another complicating variable that has not been addressed. The slope of the ceiling must be limited so that sprinkler skipping is avoided. NFPA 13, section 12.1.7 limits ceiling slopes to 2 in 12 or 16.7 percent. If your roof slope exceeds this value, NFPA 13 essentially becomes useless because all of the fire testing in the US occurred in buildings with ceiling slopes < 2 in 12.

I hope this helps. I could offer more but with the limited amount of information I do not feel it is prudent to proceed in offering design options.

 

[Bagge]

Thanks a lot fore a fantastic reply (!) It helped a lot. I have some additional information / questions though.

I think you are correct regarding the classification as class III encapsulated commodity.

You mention that NFPA 13 contains no data for solid pile storage height of encapsulated commodities > 15 feet. But what if you use a Control Mode Specific Application (CMSA) sprinkler, like the Large Drop (K11.2) or the Ultra K17 (K16.8) (Tyco)? There are not mentioned anything about encapsulated commodity in the table 14.3.1 for these two types of sprinklers. Does this mean that it doesn’t matter whether or not the commodity is encapsulated? If so, I can use the one of these two sprinklers with no problem I guess.

My client is planning to install both the solid pile and the double rack storage methods. I have attached a picture of the rack storage method. Like the solid pile I can use the Large Drop sprinkler in this case also, using the table 16.2.2.1. It doesn’t say anything about encapsulation in this case either. I really think it is a bit strange that NFPA 13 doesn’t say anything about encapsulation with Control Mode Specific Application.

One last question; is it a demand that I make room for a Hose Stream allowance in my water capacity calculation, if I decide to use the NFPA 13 rules? Or is only if it is decided to apply the Hose Stream at the Sprinkler System? (Does this fragment make sense? I hope you know what I mean)