NFPA 13, Sect. 12.7 'Special Design' (aka Special Interest)

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NFPA 13, Sect. 12.7 'Special Design' (aka Special Interest)

Postby Blackstone on Wed Dec 10, 2008 11:42 am

Notice regarding High-Piled Storage using 2x6 wood slats w/2" space for shelving

120-3-3-.04(6)(c) modifies Chapter 12 of the 2002 edition of NFPA 13, specifically criteria from Section 12.7, “Special Designs”, for High-Rack Storage of nonencapsulated Class I thru IV commodities, including Cartoned or Exposed Nonexpanded Group A Plastics:

Section, Item (2) indicates Shelves shall be slatted using a minimum nominal 2 inches (51mm) thick by maximum 6-inches (152.4mm) wide slat held in place by spacers secured to the racks (pop-rivets, screws, spot welds, etc.) that maintain a minimum of 2 inches (51mm) opening in each slat (wire mesh shelves with greater than 50% openings may be used in lieu of slatted shelves to prevent solid shelf requirements when spacers are not able to be secured to the racks). Information on the method of ‘securing’ the spacers (or if wire mesh will be used, information on this type of ‘open’ shelving) to the racks must be submitted for review and approval ~ please note that securing the spacer to a slat as has been proposed in the past is not acceptable as this does not comply with the above section which requires the spacer to be secured to the rack. Securing the spacer to the rack provides evidence of the spacer's intentional removal - if only attached to the wooden slats, which can be easily replaced, no evidence that the spacers were ever installed and then removed is left behind (i.e. empty screw holes, vacant pop-rivet holes, etc.).

Without the securing of the spacer to the rack, these spacers become mysteriously 'lost' (removed to permit sliding the slats together to form a solid shelf which would then void the use of Section 12.7 and require in-rack sprinklers). When these spacers that are not secured to the rackes to prevent them from 'falling-out', getting 'omitted', etc., become missing, the engineers blame the store manager for not maintaining them and even the AHJ for not enforcing the requirement, and the store manager blames the engineer for providing such a lame system and the AHJ for approving it...

The following sections of 12.7 were also modified to reflect the full scale testing of the EC-25 fire sprinkler (or rather lack of testing for these specific scenario's of concern):

Section, Item (4) Solid plywood shelving (3ft 6in x 8ft 3in) shall be permissible over the wood slats at the 5-ft level provided that shelves per items (5) are not installed in the same bay and item (13) is not used within 4-ft of the same bay.

Section, Item (7) Solid veneered particleboard displays shall be permissible provided that: all flue spaces are maintained; only one is installed per bay up to the 12-ft level; the top of the display is open to either shelves with spacers or wire mesh shelves; shelves per item (4) or (5) are not installed in the bay and item (13) is not used within 4-ft of the bay; and sprinkler spacing within 15-ft of the bays with displays are spaced a maximum of 12-ft apart.

Section, Item (13) Storage in aisles shall be permissible provided the aisle storage is not more than 4-ft high, a minimum clear aisle width of 4-ft is maintained, and aisle storage shall not exceed 16 sq.ft. per 120 sq.ft. of aisle area.

The title paragraph was also modified:

Section 12.7:
12.7 Special Designs. Special designs using criteria from this section shall be permitted subject to Authority Having Jurisdiction approval. Use of this section’s criteria shall require that a Rack Plan be maintained and be made available to the Authority Having Jurisdiction upon demand. This plan shall indicate the Section containing the criteria used for the design and shall be on a bay by bay basis where ever designs from this Section are used.
We find consulations, we learn tricks with which we deceive ourselves, but the essential thing - the way - we do not find. Listen to the river.

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