Packaging Arrangement
The finished roll stock product is stored encapsulated on racks. The storage height is a maximum of 22 feet – 6 inches. The rack storage widths are 96 inches, and the aisle widths are 150 inches.
Design Criteria
Based on the commodity classification (Group A plastics) and storage arrangement (racks), the finished roll stock is required to meet the provisions of NFPA 13, Chapter 17 – Protection of Plastic and Rubber Commodities That Are Stored on Racks.
According to Figure 17.1.2.1,the Finished Roll Stock storage arrangement is Plastics > Group A > Exposed, Unexpanded > Stableand directs us to follow the guidelines of Chapter 17.
Section 17.1.2.4 requires storage up to 25 feet to meet the requirements of Section 17.2.
Section 17.1.4.1 requires fire sprinkler protection for steel columns that have not been provided with fireproofing, where the storage height exceeds 15 feet. The most common protection method is to provide sidewall sprinklers at the 15 foot elevation that is pointed toward one side of the steel column. Per Section 17.1.4.2, these sprinklers are not required to be included in the hydraulic model.
Figure 17.2.1.2.1 (e) provides the sprinkler density requirements for 25 foot storage with less than 5 foot clearance to ceilings. If ceiling only sprinklers are used, the fire sprinklers’ k-factor must be 16.8 with a design density of 0.80 gpm/sqft over the most remote 2,000 square feet. Otherwise, two levels of in-rack sprinklers operating at 15 psi are required with a design density of 0.30 gpm/sqft over 2,000 square feet. The following Table provides four design options for fire sprinkler protection of the storage.
|
|
Sprinkler Type |
Density |
Area |
Sprinkler k-factor |
Duration (mins) |
|
1 |
Ceiling Sprinklers Only |
0.80 gpm/sqft |
2,000 sqft |
16.8 |
90 |
|
2 |
In-rack sprinklers (2 levels) |
0.30 gpm/sqft |
2,000 sqft |
½ inch, 17/32 inch |
90 |
|
3 |
In-rack sprinklers (1 level) |
0.45 gpm/sqft |
2,000 sqft |
17/32 inch @ 15 psi |
90 |
|
4 |
In-rack sprinklers (1 level) |
0.45 gpm/sqft |
2,000 sqft |
½ inch @ 30 psi |
90 |