Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

NFPA 13 2013 Tire storage

Kris Mills

Mechanical
Sep 19, 2024
2
Good afternoon,

during discussion with a particular client, there is a mezzanine used to putting tires on cars where there will be storage of tires.

It is a mezzanine of 17 ft height. storage is to be maximized (12ft). Laced storage and portable steel racks.
Screenshot_2024-09-19_131247_kyqyqs.png


Looking at table 18.4 (d), it seems to me that we are stuck with pile height up to 25ft, building height 30 ft. meaning we are stuck with that severely punishing design. If laced is the defining storage design and maximum storage height is desired, is there something else im missing?

Is it safe to make this leap in interpolation?
 
Replies continue below

Recommended for you

Unless you are a PE or FPE I would not make any attempt at interpolation. Very dangerous thing to do.

Laced tires are a killer and while I don't know why but it has always been that way.

I did a lot of work at tire plants and I've never seen laced tire storage. Make sure they are doing or give an alternate price if they don't do laced.

This is from the 2019 edition of NFPA #13 which you can use by reading the equivalency clause.

TABLE 21.6.1(b) Control Mode Density/Area Sprinklers System Density (gpm/ft2) for Palletized Portable Rack Storage and Fixed Rack Storage of Rubber Tires with Pallets Over 5 ft (1.5 m) to 20 ft (3.7 m) in Height

Looks to me like we have a density of 0.39/2000 using high temp heads.

Even if the 2013 edition is the adopted one in your state you can use a later version due to the Equivalency clause found in every NFPA #13 standard:

1.5 Equivalency.
Nothing in this standard is intended to prevent the use of systems, methods, or devices of equivalent or superior quality, strength, fire resistance, effectiveness, durability, and safety over those prescribed by this standard

 
I am the FPE for this project. client absolutely wants the ability to have portable rack laced tires to 12 feet.

Using CMDA, you end up with a 0.6 over 5000 sq ft design area, going over 12 ft.

This puts it at the limit the city can give based upon the flow test data (not tested past 3400gpm). Additionally, you would also have to calculate at 0.9/3000.

ESFR design does not explain the relevance in the distance from the top of storage to top of ceiling. ie the up to 25ft storage in 30ft max building, vs 30ft storage in 40 ft building.

FM data sheet 8-3 does not go into such an analysis.

Given NFPA 13 is my applicable code, it is a conundrum.

I have never seen this arrangement so desired as well.

I do appreciate the insight.
 
Has the city adopted IFC?

As in if they did, are you doing high piled storage design?
 
Please tell me what a laced tire is? All that comes to mind is "Old Mother Hubbard" that lived in a laced high top shoe.

Best regards - Al
 

Part and Inventory Search

Sponsor