NFPA 13-2013 Table 18.4(a) 'see Note 1' 1

[skdesigner]

I have been asked to provide comment on the following situation:

Existing flat roof warehouse, OWSJ roof construction, roof deck approx. 28' above floor, control-mode density area sprinkler system (complete with 11.2k uprights and a fire pump). Potential new tenant wants to store tires in said building, and wants to know maximum height of storage. Based on Table 18.4(a), there are several options that could feasibly work (as some of those options top out at 5'-0, it isn't really the answer anyone is looking for). However, the top row of Table 18.4(a) contains two instances where the text 'see Note 1' appears. Note 1 states 'Sprinkler discharge densities and areas of application are based on a maximum clearance to ceiling of 10 ft with the maximum height of storage anticipated'.

I am familiar with the excessive clearance modifiers in chapter 12, and they do not appear to address chapter 18 situations.

Does this then mean that for storage heights less than 18' (i.e 10' lower than the 28' roof deck), storage of tires would not be permitted at all with the existing system? That is how I read it, but I confess that I tend to err on the side of caution in these matters.

Thank you in advance.

 

[Cidona]

Seems to me that the criteria in 18.4(a) are determined with a max 10' clearance.
Is the facility a dedicated tire storage facility? How big a facility are you looking at? How much of the space is to be tire storage?
Depending on those answers might Miscellaneous storage criteria be used? (Using table 13.2.1 would seem to permit storage up to 12' with a 32' ceiling with a EH1 design criteria).

 

[skdesigner]

The plan is indeed for it to be a dedicated tire storage warehouse, so ch. 13 is out of the question.

I checked every edition all the way back to the old 231D, and the verbiage of that note has changed several times over the years:

231D-98 Table 4-1.2(a) Note 2: Sprinkler discharge densities and areas of application are based on a maximum clearance of 10 ft between sprinkler deflectors and the maximum available height of storage. The maximum clearance is noted from testing and is not a definitive measurement. The authority having jurisdiction shall use the appropriate judgment where this distance is modified.

13-07 Table 18.4(a) Note 1: Sprinkler discharge densities and areas of application are based on a maximum clearance of 10 ft between sprinkler deflectors and the maximum available height of storage. The maximum clearance is noted from actual testing and is not a definitive measurement.

13-10 Table 18.4(a) Note 1: Sprinkler discharge densities and areas of application are based on a maximum clearance of 10 ft between sprinkler deflectors and the maximum height of storage anticipated.

13-13 and 13-16 Table 18.4(a) Note 1: Sprinkler discharge densities and areas of application are based on a maximum clearance to ceiling of 10 ft with the maximum height of storage anticipated

The "...not a definitive measurement." portion has been removed, and 'clearance to sprinkler deflectors' has been changed to 'clearance to ceiling'. Reading through the NFPA 13-2013 Report on Proposals, the change from 'sprinkler deflector' to 'ceiling' was a sweeping change made to all of the storage chapters in the 2013 edition, including chapter 18.

As the jurisdiction I am in has adopted the 2013 edition, I believe the only logical conclusion is that tires cannot be stored in this building in any arrangement without system modification.

Thank you for the response, Cidona.

 

[Cidona]

"As the jurisdiction I am in has adopted the 2013 edition, I believe the only logical conclusion is that tires cannot be stored in this building in any arrangement without system modification." - that or I guess they'd have the option to store the tires in such a manner that the 10' clearance would not be exceeded so that 18.4 a or b could be applied.
Good luck with it

 

[skdesigner]

Thanks again Cidona. I see that in my long, drawn out posts I managed to leave out a critical piece of info, that being that the existing system cannot provide protection for 18' or higher storage in any piling arrangement, which would then make my conclusion slightly more logical. Appreciate the input!

 

[Cidona]

Ah, I see...So now you get to use your creative and communication skills to arrive the solution

Best of luck with it.