Heads up: There are no amended sections in this chapter.
This section shall apply to storage of materials representing the broad range of combustibles stored in racks. The requirements of Chapter 12 shall apply unless modified by this chapter. (See Section C.9.)
Sprinkler protection criteria for the storage of materials on racks shall be in accordance with Section 16.2 for storage up to 25 ft (7.6 m) and Section 16.3 for storage over 25 ft (7.6 m).
Protection criteria for Group A plastics shall be permitted for the protection of the same storage height and configuration of Class I, II, III, and IV commodities.
Rack storage in movable racks shall be protected in the same manner as multiple-row racks.
Where fireproofing of building columns is not provided and storage heights are in excess of 15 ft (4.6 m), protection of building columns within the rack structure or vertical rack members supporting the building shall be protected in accordance with one of the following:
  1. Sidewall sprinklers at the 15 ft (4.6 m) elevation, pointed toward one side of the steel column
  2. Provision of ceiling sprinkler density for a minimum of 2000 ft2 (186 m2) with ordinary 165°F (74°C) or high- temperature 286°F (141°C) rated sprinklers as shown in Table 16.1.4.1 for storage heights above 15 ft (4.6 m), up to and including 20 ft (6.1 m)
  3. Provision of CMSA or ESFR ceiling sprinkler protection

Table 16.1.4.1 Ceiling Sprinkler Densities for Protection of Steel Building Columns

Commodity Classification Aisle Width
4 ft (1.2 m) 8 ft (2.4 m)
gpm/ft2 (L/min)/m2 gpm/ft2 (L/min)/m2
Class I 0.37 15.1 0.33 13.5
Class II 0.44 17.9 0.37 15.1
Class III 0.49 20.0 0.42 17.1
Class IV 0.68 27.7 0.57 23.2
This protection shall not be required where storage in fixed racks is protected by in-rack sprinklers.
The flow from a column sprinkler(s) shall be permitted to be omitted from the sprinkler system hydraulic calculations.
Where high-expansion foam systems are used in combination with ceiling sprinklers, the minimum ceiling sprinkler design density shall be 0.2 gpm/ft2 (8.1 mm/min) for Class I, Class II, or Class III commodities or 0.25 gpm/ft2 (10.2 mm/min) for Class IV commodities for the most hydraulically remote 2000 ft2 (186 m2) operating area.
Where high-expansion foam systems are used in combination with ceiling sprinklers, the maximum submergence time shall be 7 minutes for Class I, Class II, or Class III commodities and 5 minutes for Class IV commodities.
Where high-expansion foam systems are used for storage over 25 ft (7.6 m) high up to and including 35 ft (10.7 m) high, they shall be used in combination with ceiling sprinklers.
The maximum submergence time for the high-expansion foam shall be 5 minutes for Class I, Class II, or Class III commodities and 4 minutes for Class IV commodities.
In-rack sprinklers shall not be required where high-expansion foam systems are used in combination with ceiling sprinklers.
Detectors shall be listed and shall be installed in one of the following configurations:
  1. At the ceiling only where installed at one-half the listed linear spacing [e.g., 15 ft × 15 ft (4.6 m × 4.6 m) rather than at 30 ft × 30 ft (9.1 m × 9.1 m)]; at the ceiling at the listed spacing and in racks at alternate levels
  2. Where listed for rack storage installation and installed in accordance with the listing to provide response within 1 minute after ignition using an ignition source that is equivalent to that used in a rack storage testing program
Ceiling detectors alone shall not be used where the clearance to ceiling exceeds 10 ft (3.1 m) or the height of the storage exceeds 25 ft (7.6 m).
Detectors for preaction systems shall be installed in accordance with 16.1.5.3.
Where solid shelving in single-, double-, and multiple- row racks exceeds 20 ft2 (1.86 m2) but does not exceed 64 ft2 (5.95 m2) in area, sprinklers shall not be required below every shelf, but shall be installed at the ceiling and below shelves at intermediate levels not more than 6 ft (2 m) apart vertically. (See Section C.11.)
Where solid shelving in single-, double-, and multiple- row racks exceeds 64 ft2 (5.95 m2) in area or where the levels of storage exceed 6 ft (2 m), sprinklers shall be installed at the ceiling and below each level of shelving.
Where multiple-row racks of any height have no longitudinal flue or where double-row racks with storage up 25 ft (7.6 m) in height have no longitudinal flue, the situation shall not be considered solid shelves where transverse flues exist at maximum 5 ft (1.5 m) intervals and additional in-rack sprinklers shall not be required in accordance with 16.1.6.1 and 16.1.6.2.
The maximum horizontal spacing between in-rack sprinklers shall be 10 ft (3.1 m).
Where the criteria in 16.1.6.5 are not met, the water demand for the in-rack sprinklers shall be based on a minimum flow of 30 gpm (114 L/min) discharging from the following number of sprinklers balanced to the ceiling sprinkler demand in accordance with Section 23.8:
  1. Six sprinklers where only one level of in-rack sprinklers is installed to protect Class I, Class II, or Class III commodity
  2. Eight sprinklers where only one level of in-rack sprinklers is installed to protect Class IV commodity
  3. Ten sprinklers (five on each of the top two levels) where more than one level of in-rack sprinklers is installed to protect Class I, Class II, or Class III commodity
  4. Fourteen sprinklers (seven on each of the top two levels) when more than one level of in-rack sprinklers is installed to protect Class IV commodity
The water demand for in-rack sprinklers shall not be required to be balanced to the ceiling sprinkler demand where additional face sprinklers are installed under each solid shelf at rack uprights and the in-rack sprinklers are calculated to discharge at least 60 gpm (227 L/min) from eight sprinklers.
The protection of open-top containers shall be considered outside the scope of Chapter 16. See Section C.12.
The number of sprinklers and the pipe sizing on a line of sprinklers in racks shall be restricted only by hydraulic calculations and not by any piping schedule.
When in-rack sprinklers are necessary to protect a higher-hazard commodity that occupies only a portion of the length of a rack, in-rack sprinklers shall be extended a minimum of 8 ft (2.44 m) or one bay, whichever is greater, in each direction along the rack on either side of the higher hazard. The in-rack sprinklers protecting the higher hazard shall not be required to extend across the aisle.
Where a storage rack, due to its length, requires less than the number of in-rack sprinklers specified, only those in-rack sprinklers in a single rack shall be included in the calculation.
Where required by other sections of this standard, horizontal barriers used in conjunction with in-rack sprinklers to impede vertical fire development shall be constructed of sheet metal, wood, or similar material and shall extend the full length and depth of the rack.
Barriers shall be fitted within 2 in. (51 mm) horizontally around rack uprights.
In double-row and multiple-row racks without solid shelves, a longitudinal (back-to-back clearance between loads) flue space shall not be required.
Nominal 6 in. (152.4 mm) transverse flue spaces between loads and at rack uprights shall be maintained in single-row, double-row, and multiple-row racks.
Random variations in the width of flue spaces or in their vertical alignment shall be permitted.
Nominal 6 in. (152.4 mm) transverse flue spaces between loads and at rack uprights shall be maintained in single-row, double-row, and multiple-row racks.
Nominal 6 in. (152.4 mm) longitudinal flue spaces shall be provided in double-row racks.
Random variations in the width of the flue spaces or in their vertical alignment shall be permitted.
In single-row, double-row, or multiple-row racks, a minimum 6 in. (152.4 mm) vertical clear space shall be maintained between the in-rack sprinkler deflectors and the top of a tier of storage.
Face sprinklers in such racks shall be located within the rack a minimum of 3 in. (76 mm) from rack uprights and no more than 18 in. (460 mm) from the aisle face of storage.
Longitudinal flue in-rack sprinklers shall be located at the intersection with the transverse flue space and with the deflector located at or below the bottom of horizontal load beams or above or below other adjacent horizontal rack members.
Such in-rack sprinklers shall be a minimum of 3 in. (76 mm) radially from the side of the rack uprights.
The area and density for the hydraulically remote area and the water supply shall be determined as specified in 16.2.1.2 for storage up to 12 ft (3.7 m) and 16.2.1.3 to 16.2.1.3.5 for storage over 12 ft (3.7 m).
The protection criteria for storage up to and including 12 ft (3.7 m) shall be the same as miscellaneous storage from Chapter 13.
The protection criteria in Chapter 13 shall be acceptable for storage of Class I through Class IV commodities up to and including 12 ft (3.7 m) in height. (See Table 13.2.1 for specific Class I through Class TV storage height protection criteria.)
Ceiling sprinkler water demand shall be determined in accordance with 16.2.1.3.2 for single- and double-row racks or 16.2.1.3.3 for multiple-row racks. (See Section C.14.)
For single- or double-row racks for Class I, Class II, Class III, or Class IV commodities, encapsulated or nonencapsulated in single- or double-row racks, ceiling sprinkler water demand in terms of density [gpm/ft2 (mm/min)] and area of sprinkler operation [ft2 (m2) of ceiling or roof] shall be selected from the density/area curves of Figure 16.2.1.3.2(a) through Figure 16.2.1.3.2(g) that are appropriate for each commodity and configuration as shown in Table 16.2.1.3.2 and shall be modified as appropriate by 16.2.1.3.4. These requirements shall apply to portable racks arranged in the same manner as single- or double-row racks.

FIGURE 16.2.1.3.2(a) Sprinkler System Design Curves — 20 ft (6.1 m) High Rack Storage — Class I Nonencapsulated CommoditiesConventional Pallets.

FIGURE 16.2.1.3.2(b) Sprinkler System Design Curves — 20 ft (6.1 m) High Rack Storage — Class II Nonencapsulated CommoditiesConventional Pallets.

FIGURE 16.2.1.3.2(c) Sprinkler System Design Curves — 20 ft (6.1 m) High Rack Storage — Class III Nonencapsulated CommoditiesConventional Pallets.

Note: Curves C and D also apply to ceiling sprinklers only for multiple-row rack storage up to and including 15 ft (4.57 m) high, and Figure 16.2.1.3.4.1 shall not be applied.

FIGURE 16.2.1.3.2(d) Sprinkler System Design Curves — 20 ft (6.1 m) High Rack Storage — Class IV Nonencapsulated CommoditiesConventional Pallets.

FIGURE 16.2.1.3.2(e) Single- or Double-Row Racks — 20 ft (6.1 m) High Rack StorageSprinkler System Design Curves — Class I and Class II Encapsulated CommoditiesConventional Pallets.

FIGURE 16.2.1.3.2(f) Single- or Double-Row Racks — 20 ft (6.1 m) High Rack StorageSprinkler System Design Curves — Class III Encapsulated CommoditiesConventional Pallets.

FIGURE 16.2.1.3.2(g) Single- or Double-Row Racks — 20 ft (6.1 m) High Rack StorageSprinkler System Design Curves — Class IV Encapsulated CommoditiesConventional Pallets.

Table 16.2.1.3.2 Single- or Double-Row Racks — Storage Height Over 12 ft (3.7 m) Up to and Including 25 ft (7.6 m)

Height Commodity Class Encapsulated Aisles* Sprinklers Mandatory In-Rack Ceiling Sprinkler Water Demand
With In-Rack Sprinklers Without In-Rack Sprinklers
ft m Figure Curves Apply Figure 16.2.1.3.4.1 Figure Curves Apply Figure 16.2.1.3.4.1
Over 12 ft (3.7 m) up to and including 20 ft (6.1 m) I No 4 1.2 No 16.2.1.3.2(a) C and D Yes 16.2.1.3.2(a) F and H Yes
8 2.4 A and B E and G
Yes 4 1.2 No 16.2.1.3.2(e) C and D 16.2.1.3.2(e) G and H Yes
8 2.4 A and B E and F
II No 4 1.2 No 16.2.1.3.2(b) C and D 16.2.1.3.2(b) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 No 16.2.1.3.2(e) C and D 16.2.1.3.2(e) G and H Yes
8 2.4 A and B E and F
III No 4 1.2 No 16.2.1.3.2(c) C and D 16.2.1.3.2(c) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(f) C and D
8 2.4 A and B
IV No 4 1.2 No 16.2.1.3.2(d) C and D 16.2.1.3.2(d) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(g) C and D
8 2.4 A and B
Over 20 ft (6.1 m) up to and including 22 ft (6.7 m) I No 4 1.2 No 16.2.1.3.2(a) C and D No 16.2.1.3.2(a) F and H Yes
8 2.4 A and B E and G
Yes 4 1.2 1 level 16.2.1.3.2(e) C and D
8 2.4 A and B
II No 4 1.2 No 16.2.1.3.2(b) C and D 16.2.1.3.2(b) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(e) C and D
8 2.4 A and B
III No 4 1.2 No 16.2.1.3.2(c) C and D 16.2.1.3.2(c) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(f) C and D
8 2.4 A and B
IV No 4 1.2 No 16.2.1.3.2(d) C and D 16.2.1.3.2(d) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(g) C and D
8 2.4 A and B
Over 22 ft (6.7 m) up to and including 25 ft (7.6 m) I No 4 1.2 No 16.2.1.3.2(a) C and D No 16.2.1.3.2(a) F and H Yes
8 2.4 A and B E and G
Yes 4 1.2 1 level 16.2.1.3.2(e) C and D
8 2.4 A and B
II No 4 1.2 No 16.2.1.3.2(b) C and D 16.2.1.3.2(b) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(e) C and D
8 2.4 A and B
III No 4 1.2 No 16.2.1.3.2(c) C and D 16.2.1.3.2(c) G and H Yes
8 2.4 A and B E and F
Yes 4 1.2 1 level 16.2.1.3.2(f) C and D
8 2.4 A and B
IV No 4 1.2 1 level 16.2.1.3.2(d) C and D
8 2.4 A and B
Yes 4 1.2 16.2.1.3.2(g) C and D
8 2.4 A and B
*See 16.2.1.3.2.1 for interpolation of aisle widths.
Design densities for single- and double-row racks shall be selected to correspond to aisle width. (See Section C.15.)

(A) For aisle widths between 4 ft (1.2 m) and 8 ft (2.4 m), the rules for 4 ft (1.2 m) aisle width shall be used or direct linear interpolation between the densities shall be permitted.

(B) The density given for 8 ft (2.4 m) wide aisles shall be applied to aisles wider than 8 ft (2.4 m).

(C) The density given for 4 ft (1.2 m) wide aisles shall be applied to aisles more narrow than 4 ft (1.2 m) down to 31/2 ft (1.07 m).

(D) Where aisles are more narrow than 31/2 ft (1.07 m), racks shall be considered to be multiple-row racks.

For Class I, Class II, Class III, or Class IV commodities, encapsulated or nonencapsulated, ceiling sprinkler water demand in terms of density [gpm/ft2 (mm/min)] and area of sprinkler operation [ft2 (m2) of ceiling or roof] shall be selected from the density/area curves of Figure 16.2.1.3.2(a) through Figure 16.2.1.3.2(g) that are appropriate for each commodity and configuration as shown in Table 16.2.1.3.3.1 and shall be modified as appropriate by 16.2.1.3.4. The protection criteria shall apply to portable racks arranged in the same manner as single- or double-row racks.

Table 16.2.1.3.3.1 Multiple-Row RacksRack Depth Up to and Including 16 ft (4.9 m), Aisles 8 ft (2.4 m) or Wider and Storage Height Over 12 ft (3.7 m) Up to 25 ft (7.6 m)

Height Commodity Class Encapsulated Sprinklers Mandatory In-Rack Ceiling Sprinkler Water Demand
With In-Rack Sprinklers Without In-Rack Sprinklers
Figure Curves Apply Figure 16.2.1.3.4.1 1.25 × Density Figure Curves Apply Figure 16.2.1.3.4.1 1.25 × Density
Over 12 ft (3.7 m) up to and including 15 ft (4.6 m) I No No 16.2.1.3.2(a) C and D Yes No 16.2.1.3.2(a) I and J Yes No
Yes 16.2.1.3.2(a) Yes 16.2.1.3.2(a) I and J Yes
II No 16.2.1.3.2(b) No 16.2.1.3.2(b) I and J Yes No
Yes 16.2.1.3.2(b) Yes 16.2.1.3.2(b) I and J Yes
III No No 16.2.1.3.2(c) No 16.2.1.3.2(c) I and J Yes No
Yes 1 level 16.2.1.3.2(c) Yes NA NA NA
IV No No 16.2.1.3.2(d) No 16.2.1.3.2(d) C and D No No
Yes 1 level 16.2.1.3.2(d) A and B 1.50 × Density NA NA NA
Over 15 ft (4.6 m) up to and including 20 ft (6.1 m) I No No 16.2.1.3.2(a) C and D Yes No 16.2.1.3.2(a) I and J Yes No
Yes 16.2.1.3.2(a) Yes 16.2.1.3.2(a) I and J Yes
II No 16.2.1.3.2(b) No 16.2.1.3.2(b) I and J Yes No
Yes 16.2.1.3.2(b) Yes 16.2.1.3.2(b) I and J Yes
III No No 16.2.1.3.2(c) No 16.2.1.3.2(c) I and J Yes No
Yes 1 level 16.2.1.3.2(c) Yes NA NA NA NA
IV No 1 level 16.2.1.3.2(d) No
Yes 16.2.1.3.2(d) A and B 1.50 × Density
Over 20 ft (6.1 m) up to and including 25 ft (7.6 m) I No No 16.2.1.3.2(a) C and D No No 16.2.1.3.2(a) I and J Yes No
Yes 1 level 16.2.1.3.2(a) Yes NA NA NA NA
II No 1 level 16.2.1.3.2(b) No
Yes 16.2.1.3.2(b) Yes
III No 16.2.1.3.2(c) No
Yes 16.2.1.3.2(c) Yes
IV No 2 levels 16.2.1.3.2(d) No
Yes 16.2.1.3.2(d) A and B 1.50 × Density
NA: Not applicable.
For Class I, Class II, Class III, or Class IV commodities, encapsulated or nonencapsulated, ceiling sprinkler water demand in terms of density [gpm/ft2 (mm/min)] and area of sprinkler operation [ft2 (m2) of ceiling or roof] shall be selected from the density/area curves of Figure 16.2.1.3.2(a) through Figure 16.2.1.3.2(g) that are appropriate for each commodity and configuration as shown in Table 16.2.1.3.3.2 and shall be modified as appropriate by 16.2.1.3.4. The protection criteria shall apply to portable racks arranged in the same manner as single-, double-, or multiple- row racks.

Table 16.2.1.3.3.2 Multiple-Row RacksRack Depth Over 16 ft (4.9 m) or Aisles Narrower Than 8 ft (2.4 m), Storage Height Over 12 ft (3.7 m) Up to and Including 25 ft (7.6 m)

Height Commodity Class Encapsulated Sprinklers Mandatory In-Rack Ceiling Sprinkler Water Demand
With In-Rack Sprinklers Without In-Rack Sprinklers
Figure Curves Apply Figure 16.2.1.3.4.1 1.25 × Density Figure Curves Apply Figure 16.2.1.3.4.1 1.25 × Density
Over 12 ft (3.7 m) up to and including 15 ft (4.6 m) I No No 16.2.1.3.2(a) C and D Yes No 16.2.1.3.2(a) I and J Yes No
Yes 16.2.1.3.2(a) Yes 16.2.1.3.2(a) I and J Yes
II No 16.2.1.3.2(b) No 16.2.1.3.2(b) I and J Yes No
Yes 16.2.1.3.2(b) Yes 16.2.1.3.2(b) I and J Yes
III No 16.2.1.3.2(c) No 16.2.1.3.2(c) I and J Yes No
Yes 1 level 16.2.1.3.2(c) Yes
IV No No 16.2.1.3.2(d) No 16.2.1.3.2(d) C and D No No
Yes 1 level 16.2.1.3.2(d) 1.50 × Density
Over 15 ft (4.6 m) up to and including 20 ft (6.1 m) I No 1 level 16.2.1.3.2(a) C and D Yes No NA NA NA NA
Yes 16.2.1.3.2(a) Yes
II No 16.2.1.3.2(b) No
Yes 16.2.1.3.2(b) Yes
III No 16.2.1.3.2(c) No
Yes 16.2.1.3.2(c) Yes
IV No 16.2.1.3.2(d) No
Yes 16.2.1.3.2(d) 1.50 × Density
Over 20 ft (6.1 m) up to and including 25 ft (7.6 m) I No 1 level 16.2.1.3.2(a) C and D No No NA NA NA NA
Yes 16.2.1.3.2(a) Yes
II No 16.2.1.3.2(b) No
Yes 16.2.1.3.2(b) Yes
III No 16.2.1.3.2(c) No
Yes 16.2.1.3.2(c) Yes
IV No 2 levels 16.2.1.3.2(d) No
Yes 16.2.1.3.2(d) 1.50 × Density
NA: Not applicable.
For storage height over 12 ft (3.7 m) up to and including 25 ft (7.6 m) protected with ceiling sprinklers only and for storage height over 12 ft (3.7 m) up to and including 20 ft (6.1 m) protected with ceiling sprinklers and minimum required in-rack sprinklers, densities obtained from design curves shall be adjusted in accordance with Figure 16.2.1.3.4.1.

FIGURE 16.2.1.3.4.1 Ceiling Sprinkler Density vs. Storage Height.

For storage height over 20 ft (6.1 m) up to and including 25 ft (7.6 m) protected with ceiling sprinklers and minimum required in-rack sprinklers, densities obtained from design curves shall be used. Densities shall not be adjusted in accordance with Figure 16.2.1.3.4.1.
For storage height over 12 ft (3.7 m) up to and including 20 ft (6.1 m) protected with ceiling sprinklers and with more than one level of in-rack sprinklers, but not in every tier, densities obtained from design curves and adjusted in accordance with Figure 16.2.1.3.4.1 shall be permitted to be reduced an additional 20 percent, as indicated in Table 16.2.1.3.4.3.

Table 16.2.1.3.4.3 Adjustment to Ceiling Sprinkler Density for Storage Height and In-Rack Sprinklers

Storage Height In-Rack Sprinklers Apply Figure 16.2.1.3.4.1 for Storage Height Adjustment Permitted Ceiling Sprinklers Density Adjustments Where In-Rack Sprinklers Are Installed
Over 12 ft (3.7 m) through 25 ft (7.6 m) None Yes None
Over 12 ft (3.7 m) through 20 ft (6.1 m) Minimum required Yes None
More than minimum, but not in every tier Yes Reduce density 20% from that of minimum in-rack sprinklers
In every tier Yes Reduce density 40% from that of minimum in-rack sprinklers
Over 20 ft (6.1 m) through 24 ft (7.5 m) Minimum required No None
More than minimum, but not in every tier No Reduce density 20% from that of minimum in-rack sprinklers
In every tier No, Reduce density 40% from that of minimum in-rack sprinklers
For storage height over 20 ft (6.1 m) up to and including 25 ft (7.6 m) protected with ceiling sprinklers and with more than the minimum required level of in-rack sprinklers, but not in every tier, densities obtained from design curves shall be permitted to be reduced 20 percent, as indicated in Table 16.2.1.3.4.3. Densities shall not be adjusted in accordance with Figure 16.2.1.3.4.1 for storage height.
For storage height over 12 ft (3.7 m) up to and including 20 ft (6.1 m) protected with ceiling sprinklers and in-rack sprinklers at each tier, densities obtained from design curves and adjusted in accordance with Figure 16.2.1.3.4.1 shall be permitted to be reduced an additional 40 percent, as indicated in Table 16.2.1.3.4.3.
For storage height over 20 ft (6.1 m) up to and including 25 ft (7.6 m) protected with ceiling sprinklers and in-rack sprinklers at each tier, densities obtained from design curves shall be permitted to be reduced 40 percent, as indicated in Table 16.2.1.3.4.3. Densities shall not be adjusted in accordance with Figure 16.2.1.3.4.1 for storage height.
Where solid, flat-bottom, combustible pallets (slave pallets) are used with storage height up to and including 25 ft (7.6 m), the densities that are indicated in the design curves shown in Figure 16.2.1.3.2(a) through Figure 16.2.1.3.2(g), based on conventional pallets, shall be increased 20 percent for the given area.

(A) The percentage shall be applied to the density determined in accordance with Figure 16.2.1.3.4.1.

(B) The increase in density shall not apply where in-rack sprinklers are installed in accordance with Table 16.2.1.3.4.3.

For solid shelf rack storage, Table 16.2.1.3.2 shall be used to establish the density/area criteria and in-rack sprinklers shall be installed in accordance with 16.1.6.
In single- or double-row racks without solid shelves, in-rack sprinklers shall be installed in accordance with Table 16.2.1.3.2.
In multiple-row racks no deeper than 16 ft (4.9 m) with aisles 8 ft (2.4 m) or more in width, in-rack sprinklers shall be installed in accordance with Table 16.2.1.3.3.1.
In multiple-row racks deeper than 16 ft (4.9 m) or with aisles less than 8 ft (2.4 m) wide, in-rack sprinklers shall be installed in accordance with Table 16.2.1.3.3.2.
In-rack sprinklers at one level only for storage up to and including 25 ft (7.6 m) high shall be located at the first tier level at or above one-half of the storage height.
In-rack sprinklers at two levels only for storage up to and including 25 ft (7.6 m) high shall be located at the first tier level at or above one-third and two-thirds of the storage height.
Maximum horizontal spacing of in-rack sprinklers in single- or double-row racks up to and including 25 ft (7.6 m) in height shall be in accordance with Table 16.2.1.4.2.1.

Table 16.2.1.4.2.1 In-Rack Sprinkler Spacing for Class I, II, III, and IV Commodities Stored in Single- or Double-Row Racks Up to 25 ft (7.6 m) in Height Protected by Control Mode Density/Area Sprinklers at the Ceiling

Encapsulated Aisle Widths Commodity Class
I and II III IV
ft m ft m ft m ft m
No 8 2.4 12 3.7 12 3.7 10 3.0
No 4 1.2 12 3.7 10 3.0 10 3.0
Yes 8 2.4 8 2.4 8 2.4
Maximum horizontal spacing and maximum area of coverage of in-rack sprinklers on branch lines, in multiple-row racks with storage up to and including 25 ft (7.6 m) in height, shall be in accordance with Table 16.2.1.4.2.2.

Table 16.2.1.4.2.2 In-Rack Sprinkler Spacing for Class I, II, III, and IV Commodities Stored in Multi-Row Racks Up to 25 ft (7.6 m) in Height Protected by Control Mode Density/Area Sprinklers at the Ceiling

Commodity Class
I, II, III IV
Spacing Area Spacing Area
ft m ft2 m2 ft m ft2 m2
12 3.7 100 9.3 8 2.4 80 7.4

(A) The rack plan view shall be considered in determining the area covered by each sprinkler.

(B) The aisles shall not be included in area calculations.

In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues while not exceeding the maximum spacing rules.

(A) Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.

(B) Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.

The elevation of in-rack sprinkler deflectors with respect to storage shall not be a consideration in single- or double-row rack storage up to and including 20 ft (6.1 m) high. (See Section C.16.)
In single- or double-row racks without solid shelves with storage over 20 ft (6.1 m) high, or in multiple-row racks, or in single- or double-row racks with solid shelves and storage height up to and including 25 ft (7.6 m), a minimum of 6 in. (152 mm) vertical clear space shall be maintained between the in-rack sprinkler deflectors and the top of a tier of storage.

(A) Sprinkler discharge shall not be obstructed by horizontal rack members.

For multiple-row racks, a minimum of 6 in. (152 mm) shall be maintained between the in-rack sprinkler deflector and the top of a tier of storage.
Sprinklers installed in racks shall be spaced without regard to rack uprights. (See Section C.17.)
The water demand for sprinklers installed in racks shall be based on simultaneous operation of the most hydraulically remote sprinklers as follows:
  1. Six sprinklers where only one level is installed in racks with Class I, Class II, or Class III commodities
  2. Eight sprinklers where only one level is installed in racks with Class IV commodities
  3. Ten sprinklers (five on each two top levels) where more than one level is installed in racks with Class I, Class II, or Class III commodities
  4. Fourteen sprinklers (seven on each two top levels) where more than one level is installed in racks with Class IV commodities
Where a storage rack, due to its length, requires less than the number of in-rack sprinklers specified in 16.2.1.4.3.1(1) through 16.2.1.4.3.1(4), only those in-rack sprinklers in a single rack shall be included in the calculation.
Protection of single-, double-, and multiple-row rack storage without solid shelves for Class I through Class IV commodities shall be in accordance with Table 16.2.2.1.

Table 16.2.2.1 CMSA Sprinkler Design Criteria for Rack Storage of Class I Through Class IV Commodities (Encapsulated and Nonencapsulated) Stored Up to and Including 25 ft (7.6 m) in Height

Storage Arrangement Commodity Class Maximum Storage Height Maximum Ceiling/Roof Height K-Factor/Orientation Type of System Number of Design Sprinklers Minimum Operating Pressure
ft m ft m psi bar
Single-, double-, and multiple-row racks without solid shelves (no open-top containers) Class I or II 20 6.1 30 9.1 11.2 (160) Upright Wet 15 25 1.7
Dry 25 25 1.7
16.8 (240) Upright Wet 15 10 0.7
Dry 25 15 1.0
19.6 (280) Pendent Wet 15 16 1.1
25 7.6 30 9.1 11.2 (160) Upright Wet 20 25 1.7
Dry 30 25 1.7
16.8 (240) Upright Wet 15 10 0.7
Dry 30 15 1.0
19.6 (280) Pendent Wet 15 16 1.1
Class III 20 6.1 30 9.1 11.2 (160) Upright Wet 15 25 1.7
Dry 25 25 1.7
16.8 (240) Upright Wet 15 15 1.0
Dry 25 15 1.0
19.6 (280) Pendent Wet 15 16 1.1
25 7.6 30 9.1 11.2 (160) Upright Wet 15 + 1 level of in-rack 25 1.7
Dry 25 + 1 level of in-rack 25 1.7
16.8 (240) Upright Wet 15 22 1.5
Dry 25 + 1 level of in-rack 15 1.0
19.6 (280) Pendent Wet 15 16 1.1
35 10.6 11.2 (160) Upright Wet 15 + 1 level of in-rack 25 1.7
Dry 25 + 1 level of in-rack 25 1.7
16.8 (240) Upright Wet 15 + 1 level of in-rack 15 1.0
Dry 25 + 1 level of in-rack 15 1.0
19.6 (280) Pendent Wet 15 25 1.7
40 12.1 19.6 (280) Pendent Wet 15 30 2.1
Class IV 20 6.1 25 7.6 11.2 (160) Upright Wet 15 50 3.5
16.8 (240) Upright Wet 15 22 1.5
19.6 (280) Pendent Wet 15 16 1.1
30 9.1 11.2 (160) Upright Wet 20 50 3.5
15 75 5.2
16.8 (240) Upright Wet 15 22 1.5
19.6 (280) Pendent Wet 15 16 1.1
  25 7.6 30 9.1 11.2 (160) Upright Wet 15 + 1 level of in-rack 50 3.5
16.8 (240) Upright Wet 15 22 1.5
19.6 (280) Pendent Wet 15 16 1.1
35 10.6 11.2 (160) Upright Wet 20 + 1 level of in-rack 50 3.5
15 + 1 level of in-rack 75 5.2
16.8 (240) Upright Wet 20 + 1 level of in-rack 22 1.5
15 + 1 level of in-rack 35 2.4
19.6 (280) Pendent Wet 15 25 1.7
40 12.1 19.6 (280) Pendent Wet 15 30 2.1
Where in-rack sprinklers are required by Table 16.2.2.1, in-rack sprinkler spacing, design pressure, and hydraulic calculation criteria shall be in accordance with the requirements of 16.2.2.7 as applicable for the commodity.
Protection shall be provided as specified in Table 16.2.2.1 or appropriate NFPA standards in terms of minimum operating pressure and the number of sprinklers to be included in the design area.
Where CMSA sprinklers are installed under open wood joist construction, their minimum operating pressure shall be 50 psi (3.4 bar) for a K-11.2 (160) sprinkler or 22 psi (1.5 bar) for a K-16.8 (240) sprinkler.
Where each joist channel of open wood joist construction is fully firestopped to its full depth at intervals not exceeding 20 ft (6.1 m), the lower pressures specified in Table 16.2.2.1 shall be permitted to be used.
For the purpose of using Table 16.2.2.1, preaction systems shall be classified as dry pipe systems.
Building steel shall not require special protection where Table 16.2.2.1 is applied as appropriate for the storage configuration.
Where in-rack sprinklers are required by Table 16.2.2.1, in-rack sprinklers shall be installed at the first tier level at or above one-half of the storage height.
The minimum of 6 in. (152.4 mm) vertical clear space shall be maintained between the sprinkler deflectors and the top of a tier of storage.
In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues.
The maximum horizontal distance between inrack sprinklers shall be 8 ft (1.5 m).
Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues, and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.
Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.
The water demand for in-rack sprinklers shall be based on simultaneous operation of the most hydraulically remote eight sprinklers.
In-rack sprinklers shall discharge at not less than 15 psi (1 bar) for all classes of commodities. (See Section C.19.)
Protection of single-, double-, and multiple-row rack storage of Class I through Class IV commodities shall be in accordance with Table 16.2.3.1.

Table 16.2.3.1 ESFR Sprinkler Protection of Rack Storage Without Solid Shelves of Class I Through Class IV Commodities Stored Up to and Including 25 ft (7.6 m) in Height

Storage Arrangement Commodity Maximum Storage Height Maximum Ceiling/Roof Height Nominal K-Factor Orientation Minimum Operating Pressure In-Rack Sprinkler Requirements
ft m ft m psi bar
Single-row, double-row, and multiple-row racks (no open-top containers) Class I, II, III, or IV, encapsulated or unencapsulated 20 6.1 25 7.6 14.0 (200) Upright/pendent 50 3.4 No
16.8 (240) Upright/pendent 35 2.4 No
22.4 (320) pendent 25 1.7 No
25.2 (360) Pendent 15 1.0 No
30 9.1 14.0 (200) Upright/pendent 50 3.4 No
16.8 (240) Upright/pendent 35 2.4 No
22.4 (320) Pendent 25 1.7 No
25.2 (360) Pendent 15 1.0 No
35 10.7 14.0 (200) Upright/pendent 75 5.2 No
16.8 (240) Upright/pendent 52 3.6 No
22.4 (320) Pendent 35 2.4 No
25.2 (360) Pendent 20 1.4 No
40 12.2 or 12.1 16.8 (240) Pendent 52 3.6 No
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 25 1.7 No
45 13.7 14.0 (200) Pendent 90 6.2 Yes
16.8 (240) Pendent 63 4.4 Yes
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 40 2.8 No
25 7.6 30 9.1 14.0 (200) Upright/pendent 50 3.4 No
16.8 (240) Upright/pendent 35 2.4 No
22.4 (320) Pendent 25 1.7 No
25.2 (360) Pendent 15 1.0 No
32 9.8 14.0 (200) Upright/pendent 60 4.1 No
16.8 (240) Upright/pendent 42 2.9 No
35 10.7 14.0 (200) Upright/pendent 75 5.2 No
16.8 (240) Upright/pendent 52 3.6 No
22.4 (320) Pendent 35 2.4 No
25.2 (360) Pendent 20 1.4 No
40 12.2 or 12.1 16.8 (240) Pendent 52 3.6 No
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 25 1.7 No
45 13.7 14.0 (200) Pendent 90 6.2 Yes
16.8 (240) Pendent 63 4.4 Yes
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 40 2.8 No
ESFR sprinklers shall not be permitted to protect storage on solid shelf racks unless the solid shelf racks are protected with in-rack sprinklers in accordance with 16.1.6.
ESFR sprinklers shall not be permitted to protect storage with open top containers.
ESFR sprinkler systems shall be designed such that the minimum operating pressure is not less than that indicated in Table 16.2.3.1 for type of storage, commodity, storage height, and building height involved.
The design area shall consist of the most hydraulically demanding area of 12 sprinklers, consisting of four sprinklers on each of three branch lines.
Where required by Table 16.2.3.1, in-rack sprinklers shall be installed at the first tier level at or above one-half of the storage height.
In-rack sprinklers shall be K-8.0 (115) or K-11.2 (160) quick-response, ordinary-temperature sprinklers.
The minimum of 6 in. (152.4 mm) vertical clear space shall be maintained between the sprinkler deflectors and the top of a tier of storage.
The maximum horizontal distance between in-rack sprinklers shall be 5 ft (1.5 m).
In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues while not exceeding the maximum spacing rules.
Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues, and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.
Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.
The water demand for sprinklers installed in racks shall be based on simultaneous operation of the most hydraulically remote eight sprinklers.
Each of the in-rack sprinklers described in 16.2.3.6.8 shall discharge at a minimum of 60 gpm (227 L/min).
Slatted rack shelves shall be considered equivalent to solid rack shelves where the shelving is not considered open rack shelving or where the requirements of 16.2.4.1.2 are not met. (See Section C.20.)
A wet pipe system that is designed to provide a minimum of 0.6 gpm/ft2 (24.5 mm/min) density over a minimum area of 2000 ft2 (186 m2) or K-14.0 (200) ESFR sprinklers operating at a minimum of 50 psi (3.4 bar), K-16.8 (240) sprinklers operating at a minimum of 32 psi (2.2 bar), K-22.4 (320) ESFR sprinklers operating at a minimum of 25 psi (1.7 bar), or K-25.2 (360) ESFR sprinklers operating at a minimum of 15 psi (1 bar) shall be permitted to protect single-row and double-row racks with slatted rack shelving where all of the following conditions are met:
  1. Sprinklers shall be K-11.2 (160), K-14.0 (200), or K-16.8 (240) orifice spray sprinklers with a temperature rating of ordinary, intermediate, or high and shall be listed for storage occupancies or shall be K-14.0 (200), K-16.8 (240), K-22.4 (320) ESFR, or K-25.2 (360) ESFR.
  2. The protected commodities shall be limited to Class I through Class IV, Group B plastics, Group C plastics, cartoned (expanded and unexpanded) Group A plastics, and exposed (unexpanded) Group A plastics.
  3. Slats in slatted rack shelving shall be a minimum nominal 2 in. (51 mm) thick by maximum nominal 6 in. (152 mm) wide, with the slats held in place by spacers that maintain a minimum 2 in. (51 mm) opening between each slat.
  4. Where K-11.2 (160), K-14.0 (200), or K-16.8 (240) orifice sprinklers are used, there shall be no slatted shelf levels in the rack above 12 ft (3.7 m). Open rack shelving using wire mesh shall be permitted for shelf levels above 12 ft (3.7 m).
  5. Transverse flue spaces at least 3 in. (76 mm) wide shall be provided at least every 10 ft (3.1 m) horizontally.
  6. Longitudinal flue spaces at least 6 in. (152 mm) wide shall be provided for double-row racks. Longitudinal flue spaces shall not be required where ESFR sprinklers are used.
  7. The aisle widths shall be at least 71/2 ft (2.3 m).
  8. The maximum roof height shall be 27 ft (8.2 m) or 30 ft (9.1 m) where ESFR sprinklers are used.
  9. The maximum storage height shall be 20 ft (6.1 m).
  10. Solid plywood or similar materials shall not be placed on the slatted shelves so that they block the 2 in. (51 mm) spaces between slats, nor shall they be placed on wire mesh shelves.
For single- and double-row racks, the water demand for nonencapsulated storage without solid shelves separated by aisles at least 4 ft (1.2 m) wide and with not more than 10 ft (3.1 m) between the top of storage and the sprinklers shall be in accordance with Table 16.3.1.1.

Table 16.3.1.1 Single- or Double-Row Racks Without Solid Shelves of Class I Through Class IV Commodities Stored Over 25 ft (7.6 m) in Height with Aisles 4 ft (1.2 m) or More in Width

Commodity Class In-Rack Sprinklers Approximate Vertical Spacing at Tier Nearest the Vertical Distance and Maximum Horizontal Spacinga,b,c Figure Maximum Storage Height Stagger Ceiling Sprinkler Operating Area Ceiling Sprinkler Density Clearance to Ceiling Up to 10 ft (3.1 m)g
Ordinary Temperature High Temperature
Longitudinal Flued Facee,f ft2 m2 gpm/ft2 mm/min gpm/ft2 mm/min
I Vertical 20 ft (6.1 m) Horizontal 10 ft (3.1 m) under horizontal barriers None 16.3.4.1.1.1(a) 30 ft (9.1 m) No 2000 186 0.25 10.2 0.35 14.3
Vertical 20 ft (6.1 m) Horizontal 10 ft (3.1 m) Vertical 20 ft (6.1 m) Horizontal 10 ft (3.1 m) 16.3.4.1.1.1(b) Higher than 25 ft (7.6 m) Yes 0.25 10.2 0.35 14.3
I, II, III Vertical 10 ft (3.1 m) or at 15 ft (4.6 m) and 25 ft (7.6 m) None 16.3.4.1.1.1(c) 30 ft (9.1 m) Yes 2000 186 0.3 12.2 0.4 16.3
Vertical 10 ft (3.1 m) Horizontal 10 ft (3.1 m) Vertical 30 ft (9.1 m) Horizontal 10 ft (3.1 m) 16.3.4.1.1.1(d) Higher than 25 ft (7.6 m) Yes 0.3 12.2 0.4 16.3
Vertical 20 ft (6.1 m) Horizontal 10 ft (3.1 m) Vertical 20 ft (6.1 m) Horizontal 5 ft (1.5 m) 16.3.4.1.1.1(e) Yes 0.3 12.2 0.4 16.3
Vertical 25 ft (7.6 m) Horizontal 5 ft (1.5 m) Vertical 25 ft (7.6 m) Horizontal 5 ft (1.5 m) 16.3.4.1.1.1(f) No 0.3 12.2 0.4 16.3
Horizontal barriers at 20 ft (6.1 m) Vertical intervals — two lines of sprinklers under barriers — maximum horizontal spacing 10 ft (3.1 m), staggered 16.3.4.1.1.1(g) Yes 0.3 12.2 0.4 16.3
I, II, III, IV Vertical 15 ft (4.6 m) Horizontal 10 ft (3.1 m) Vertical 20 ft (6.1 m) Horizontal 10 ft (3.1m) 16.3.4.1.1.1(h) Higher than 25 ft (7.6 m) Yes 2000 186 0.35 14.3 0.45 18.3
Vertical 20 ft (6.1 m) Horizontal 5 ft (1.5 m) Vertical 20 ft (6.1 m) Horizontal 5 ft (1.5 m) 16.3.4.1.1.1(i) No 0.35 14.3 0.45 18.3
Horizontal barriers at 15 ft (4.6 m) Vertical intervals — two lines of sprinklers under barriers — maximum horizontal spacing 10 ft (3.1 m), staggered 16.3.4.1.1.1(j) Yes 0.35 14.3 0.45 18.3
aMinimum in-rack sprinkler discharge, 30 gpm (114 L/min).
bWalter shields required.
cAll in-rack sprinkler spacing dimensions start from the floor.
dInstall sprinklers at least 3 in. (76.2 mm) from uprights.
eFace sprinklers shall not be required for a Class I commodity consisting of noncombustible products on wood pallets (without combustible containers), except for arrays shown in Figure 16.3.1.3.1.1 (A)(g) and Figure 16.3.1.3.1.1(A)(j).
fIn Figure 16.3.1.3.1.1(A)(a) through Figure 16.3.1.3.1.1 (A)(j), each square represents a storage cube that measures 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. to 10 ft (0.46 m to 3.1 m). Therefore, there can be one load to six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.
gFor encapsulated commodity, increase density 25 percent.
Where storage as described in 16.3.1.1 is encapsulated, ceiling sprinkler density shall be 25 percent greater than for nonencapsulated storage.
For multiple-row racks, the water demand for nonencapsulated storage without solid shelves separated by aisles at least 4 ft (1.2 m) wide and with not more than 10 ft (3.1 m) between the top of storage and the sprinklers shall be in accordance with Table 16.3.1.2.

Table 16.3.1.2 Multiple-Row Racks of Class I Through Class IV Commodities Stored Over 25 ft (7.6 m) in Height

Commodity Class Encapsulated In-Rack Sprinklersa,b,c Height Limit (ft) Stagger Figure Maximum Spacing from Top of Storage to Highest In-Rack Sprinklers Ceiling Sprinkler Operating Area Ceiling Sprinklers Density Clearance to Ceiling Up to 10 ft
Maximum Vertical Spacing Maximum Horizontal Spacing in A Flue Maximum Horizontal Spacing across Flue 165° Rating 286° Rating
ft m ft m ft m ft m ft2 m2 gpm/ft2 mm/min gpm/ft2 mm/min
I No 20 6.1 12 3.7 10 3.1 None Between adjacent flues 16.3.4.1.3.1(a) 10 3.1 2000 186 0.25 10.2 0.35 14.3
Yes 0.31 0.44
I, II, and III No 15 4.6 10 3.1 10 3.1 16.3.4.1.3.1(b) 10 3.1 0.30 12.2 0.40 16.3
Yes 0.37 0.50 20.4
I, II, III, and IV No 10 3.1 10 3.1 10 3.1 16.3.4.1.3.1(c) 5 1.5 0.35 14.3 0.45 18.3
Yes 0.44 0.56
For SI units, °C = 5/9 (°F-32); 1 gpm/ft2 = 40.746 mm/min.
aAll four rack faces shall be protected by sprinklers located within the racks and no more than 18 in. (0.46 m) from the faces, as indicated in Figure 16.3.1.3.1.3(A)(a) through Figure 16.3.1.3.1.3(A)(c). It shall not be required for each sprinkler level to protect all faces.
bAll in-rack sprinkler spacing dimensions start from the floor.
cIn Figure 16.3.1.3.1.3(A)(a) through Figure 16.3.1.3.1.3(A)(c), each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. to 10 ft (0.46 m to 3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.
Where such storage is encapsulated, ceiling sprinkler density shall be 25 percent greater than for nonencapsulated storage.

(A) In double-row racks without solid shelves and with a maximum of 10 ft (3.1 m) between the top of storage and the ceiling, in-rack sprinklers shall be installed in accordance with Table 16.3.1.1 and Figure 16.3.1.3.1.1 (A)(a) through Figure 16.3.1.3.1.1 (A)(j). The highest level of in-rack sprinklers shall be not more than 10 ft (3.1 m) below the top of storage. Where a single-row rack is mixed with double-row racks, Table 16.3.1.1 and Figure 16.3.1.3.1.1(A)(a) through Figure 16.3.1.3.1.1 (A)(j) shall be used.

Notes:

  1. Symbol x indicates in-rack sprinklers.
  2. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(a) In-Rack Sprinkler Arrangement, Class I Commodities, Storage Height 25 ft to Maximum 30 ft (7.6 m to Maximum 9.1 m).

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required where loads labeled E or F represent top of storage.
  4. For storage higher than represented by loads labeled F, the cycle defined by Notes 2 and 3 is repeated, with stagger as indicated.
  5. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  6. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(b) In-Rack Sprinkler Arrangement, Class I Commodities, Storage Height Over 25 ft (7.6 m).

Notes:

  1. Alternate location of in-rack sprinklers. Sprinklers shall be permitted to be installed above loads A and C or above loads B and D.
  2. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  3. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(c) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Storage Height 25 ft to Maximum 30 ft (7.6 m to Maximum 9.1 m).

Notes:

  1. Sprinklers labeled 1 shall be required where loads labeled A represent the top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled B or C represent top of storage.
  3. Sprinklers labeled 1, 2, and 3 shall be required where loads labeled D or E represent top of storage.
  4. Sprinklers labeled 1, 2, 3, and 4 shall be required where loads labeled F or G represent top of storage.
  5. Sprinklers labeled 1, 2, 3, 4, and 5 shall be required where loads labeled H represent top of storage.
  6. For storage higher than represented by loads labeled H, the cycle defined by Notes 3, 4, and 5 is repeated with stagger as indicated.
  7. The indicated face sprinklers shall be permitted to be omitted where commodity consists of unwrapped or unpackaged metal parts on wood pallets.
  8. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  9. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(d) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Storage Height Over 25 ft (7.6 m) — Option 1.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required where loads labeled E or F represent top of storage.
  4. For storage higher than represented by loads labeled F, the cycle defined by Notes 2 and 3 is repeated, with stagger as indicated.
  5. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  6. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(e) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Storage Height Over 25 ft (7.6 m) — Option 2.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required where loads labeled E represent top of storage.
  4. Sprinklers labeled 1 and 4 shall be required where loads labeled F or G represent top of storage.
  5. For storage higher than represented by loads labeled G, the cycle defined by Notes 2, 3, and 4 is repeated.
  6. Symbol x indicates face and in-rack sprinklers.
  7. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(f) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Storage Height Over 25 ft (7.6 m) — Option 3.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required where loads labeled E or F represent top of storage.
  4. For storage higher than represented by loads labeled F, the cycle defined by Notes 2 and 3 is repeated.
  5. Symbols o, Δ, and x indicate sprinklers on vertical or horizontal stagger.
  6. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(g) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Storage Height Over 25 ft (7.6 m) — Option 4.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1, 2, and 3 shall be required where loads labeled E or F represent top of storage.
  4. Sprinklers labeled 1, 2, 3, and 4 shall be required where loads labeled G represent top of storage.
  5. Sprinklers labeled 1, 2, 3, 4, and 5 shall be required where loads labeled H represent top of storage.
  6. Sprinklers labeled 1, 2, 3, 4, and 6 (not 5) shall be required where loads labeled I or J represent top of storage.
  7. Sprinklers labeled 1, 2, 3, 4, 6, and 7 shall be required where loads labeled K represent top of storage.
  8. Sprinklers labeled 1, 2, 3, 4, 6, and 8 shall be required where loads labeled L represent top of storage.
  9. Sprinklers labeled 1, 2, 3, 4, 6, 8, and 9 shall be required where loads labeled M or N represent top of storage.
  10. For storage higher than represented by loads labeled N, the cycle defined by Notes 1 through 9 is repeated, with stagger as indicated. In the cycle, loads labeled Mare equivalent to loads labeled A.
  11. Symbols o, x, and Δ indicate sprinklers on vertical or horizontal stagger.
  12. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(h) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Storage Height Over 25 ft (7.6 m) — Option 1.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required where loads labeled C or D represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required where loads labeled E or F represent top of storage.
  4. For storage higher than represented by loads labeled F, the cycle defined by Notes 2 and 3 is repeated.
  5. Symbol x indicates face and in-rack sprinklers.
  6. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(i) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Storage Height Over 25 ft (7.6 m) — Option 2.

Notes:

  1. Sprinklers labeled 1 (the selected array from Table 16.3.1.1) shall be required where loads labeled A or B represent top of storage.
  2. Sprinklers labeled 1 and 2 and barrier labeled 1 shall be required where loads labeled C represent top of storage.
  3. Sprinklers and barriers labeled 1 and 3 shall be required where loads labeled D or E represent top of storage.
  4. For storage higher than represented by loads labeled E, the cycle defined by Notes 2 and 3 is repeated.
  5. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  6. Symbol o indicates longitudinal flue space sprinklers.
  7. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.1(A)(j) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Storage Height Over 25 ft (7.6 m) — Option 3.

(B) Figure 16.3.1.3.1.2(A)(a) through Figure 16.3.1.3.1.2(A)(c) shall be permitted to be used for the protection of the single-row racks.

(A) In single-row racks without solid shelves with storage height over 25 ft (7.6 m) and a maximum of 10 ft (3.1 m) between the top of storage and the ceiling, sprinklers shall be installed in accordance with Figure 16.3.1.3.1.2(A)(a) through Figure 16.3.1.3.1.2(A)(e).

FIGURE 16.3.1.3.1.2(A)(a) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Single-Row Racks, Storage Height Over 25 ft (7.6 m) — Option 1.

FIGURE 16.3.1.3.1.2(A)(b) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Single-Row Racks, Storage Height Over 25 ft (7.6 m) — Option 1.

FIGURE 16.3.1.3.1.2(A)(c) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Single-Row Racks, Storage Height Over 25 ft (7.6 m) — Option 2.

FIGURE 16.3.1.3.1.2(A)(d) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Single-Row Racks, Storage Height Over 25 ft (7.6 m) — Option 2.

FIGURE 16.3.1.3.1.2(A)(e) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Single-Row Racks, Storage Height Over 25 ft (7.6 m) — Option 3.

(B) In single-row racks, where figures show in-rack sprinklers in transverse flue spaces centered between the rack faces, it shall be permitted to position these in-rack sprinklers in the transverse flue at any point between the load faces.

(A) In multiple-row racks with a maximum of 10 ft (3.1 m) between the top of storage and the ceiling, protection shall be in accordance with Table 16.3.1.2 and in-rack sprinklers shall be installed as indicated in Figure 16.3.1.3.1.3(A)(a) through Figure 16.3.1.3.1.3(A)(c).

Notes:

  1. Sprinklers labeled 1 shall be required if loads labeled A represent top of storage.
  2. Sprinklers labeled 1 and 2 shall be required if loads labeled B or C represent top of storage.
  3. Sprinklers labeled 1 and 3 shall be required if loads labeled D or E represent top of storage.
  4. For storage higher than represented by loads labeled E, the cycle defined by Notes 2 and 3 is repeated, with stagger as indicated.
  5. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  6. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.3(A)(a) In-Rack Sprinkler Arrangement, Class I Commodities, Multiple-Row Racks, Storage Height Over 25 ft (7.6 m).

Notes:

  1. Sprinklers labeled 1 and 2 shall be required if loads labeled A represent top of storage.
  2. Sprinklers labeled 1 and 3 shall be required if loads labeled B or C represent top of storage.
  3. For storage higher than represented by loads labeled C, the cycle defined by Notes 2 and 3 is repeated, with stagger as indicated.
  4. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  5. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.3(A)(b) In-Rack Sprinkler Arrangement, Class I, II, or III Commodities, Multiple-Row Racks, Storage Height Over 25 ft (7.6 m).

Notes:

  1. Sprinklers labeled 1, 2, and 3 shall be required if loads labeled A represent top of storage.
  2. Sprinklers labeled 1, 2, and 4 shall be required if loads labeled B represent top of storage.
  3. For storage higher than represented by loads labeled B, the cycle defined by Notes 1 and 2 is repeated, with stagger as indicated.
  4. Symbol Δ or x indicates sprinklers on vertical or horizontal stagger.
  5. Each square represents a storage cube measuring 4 ft to 5 ft (1.2 m to 1.5 m) on a side. Actual load heights can vary from approximately 18 in. (0.5 m) up to 10 ft (3.1 m). Therefore, there could be as few as one load or as many as six or seven loads between in-rack sprinklers that are spaced 10 ft (3.1 m) apart vertically.

FIGURE 16.3.1.3.1.3(A)(c) In-Rack Sprinkler Arrangement, Class I, II, III, or IV Commodities, Multiple-Row Racks, Storage Height Over 25 ft (7.6 m).

(B) The highest level of in-rack sprinklers shall be not more than 10 ft (3.1 m) below maximum storage height for Class I, Class II, or Class III commodities or 5 ft (1.5 m) below the top of storage for Class IV commodities.

In-rack sprinklers shall be staggered horizontally and vertically where installed in accordance with Table 16.3.1.1, Figure 16.3.1.3.1.1(A)(a) through Figure 16.3.1.3.1.1 (A)(j), and Figure 16.3.1.3.1.2(A)(a) through Figure 16.3.1.3.1.2(A)(e).
In-rack sprinklers for storage higher than 25 ft (7.6 m) in double-row racks shall be spaced horizontally and located in the horizontal space nearest the vertical intervals specified in Table 16.3.1.1 and Figure 16.3.1.3.1.1 (A)(a) through Figure 16.3.1.3.1.1 (A)(j).
Maximum horizontal spacing of sprinklers in multiple-row racks with storage higher than 25 ft (7.6 m) shall be in accordance with Figure 16.3.1.3.1.3(A)(a) through Figure 16.3.1.3.1.3(A)(c).
In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues while not exceeding the maximum spacing rules.

(A) Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues, and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.

(B) Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.

The water demand for sprinklers installed in racks shall be based on simultaneous operation of the most hydraulically remote sprinklers as follows:
  1. Six sprinklers where only one level is installed in racks with Class I, Class II, or Class III commodities
  2. Eight sprinklers where only one level is installed in racks with Class IV commodities
  3. Ten sprinklers (five on each two top levels) where more than one level is installed in racks with Class I, Class II, or Class III commodities
  4. Fourteen sprinklers (seven on each two top levels) where more than one level is installed in racks with Class IV commodities
Protection of single-, double-, and multiple-row rack storage without solid shelves for Class I through Class IV commodities shall be in accordance with Table 16.3.2.1.

Table 16.3.2.1 CMSA Sprinkler Design Criteria for Rack Storage of Class I Through Class IV Commodities Stored Over 25 ft (7.6 m) in Height (Encapsulated and Nonencapsulated)

Storage Arrangement Commodity Class Maximum Storage Height Maximum Ceiling/Roof Height K-Factor/Orientation Type of System Number of Design Sprinklers Minimum Operating Pressure
ft m ft m psi bar
Single-, double-, and multiple-row racks without solid shelves (no open-top containers) Class I or II 30 9.1 35 10.6 11.2 (160) Upright Wet 20 + 1 level of in-rack 25 1.7
Dry 30 + 1 level of in-rack 25 1.7
16.8 (240) Upright Wet 20 + 1 level of in-rack 15 1.0
Dry 30 + 1 level of in-rack 15 1.0
19.6 (280) Pendent Wet 15 25 1.7
35 10.6 40 12.1 11.2 (160) Upright Dry* 36 55 3.8
16.8 (240) Upright Dry* 36 22 1.5
19.6 (280) Pendent Wet 15 30 2.1
Class III or IV 30 9.1 35 10.6 19.6 (280) Pendent Wet 15 25 1.7
35 10.6 40 12.1 19.6 (280) Pendent Wet 15 30 2.1
*High temperature-rated sprinklers shall be used. Dry system water delivery shall be determined in accordance with 7.2.3.6 with a maximum time of water delivery of 30 seconds with four sprinklers initially open.
Where in-rack sprinklers are required by Table 16.3.2.1, in-rack sprinkler spacing, design pressure, and hydraulic calculation criteria shall be in accordance with the requirements of 16.3.1.3 as applicable for the commodity.
Protection shall be provided as specified in Table 16.3.2.1 or appropriate NFPA standards in terms of minimum operating pressure and the number of sprinklers to be included in the design area.
Where CMSA sprinklers are installed under open wood joist construction, their minimum operating pressure shall be 50 psi (3.4 bar) for a K-11.2 (160) sprinkler or 22 psi (1.5 bar) for a K-16.8 (240) sprinkler.
Where each joist channel of open wood joist construction is fully firestopped to its full depth at intervals not exceeding 20 ft (6.1 m), the lower pressures specified in Table 16.3.2.1 shall be permitted to be used.
For the purpose of using Table 16.3.2.1, preaction systems shall be classified as dry pipe systems.
Building steel shall not require special protection where Table 16.3.2.1 are applied as appropriate for the storage configuration.
Where in-rack sprinklers are required by Table 16.3.2.1 in-rack sprinklers shall be installed at the first tier level at or above one-half of the storage height.
The minimum of 6 in. (152 mm) vertical clear space shall be maintained between the sprinkler deflectors and the top of a tier of storage.
In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues.
The maximum horizontal distance between in-rack sprinklers shall be 5 ft (1.5 m).
Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues, and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.
Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.
The water demand for sprinklers installed in racks shall be based on simultaneous operation of the most hydraulically remote eight sprinklers.
Sprinklers in racks shall discharge at not less than 15 psi (1 bar) for all classes of commodities. (See Section C.19.)
Protection of single-, double-, and multiple-row rack storage of Class I through Class IV commodities shall be in accordance with Table 16.3.3.1.

Table 16.3.3.1 ESFR Sprinkler Protection of Rack Storage Without Solid Shelves of Class I Through Class IV Commodities Stored Over 25 ft (7.6 m) in Height

Storage Arrangement Commodity Maximum Storage Height Maximum Ceiling/Roof Height Nominal K-Factor Orientation Minimum Operating Pressure In-Rack Sprinkler Requirements Hose Stream Allowance Water Supply Duration (hours)
ft m ft m psi bar gpm L/min
Single-, double-, and multiple-row rack (no open-top containers) Class I, II, III, or IV, encapsulated or nonencapsulated 30 9.1 35 10.7 14.0 (200) Upright/pendent 75 5.2 No 250 946 1
16.8 (240) Upright/pendent 52 3.6 No
22.4 (320) Pendent 35 2.4 No
25.2 (360) Pendent 20 1.4 No
40 12.2 No
16.8 (240) Pendent 52 3.6 No
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 25 1.7 No
45 13.7 14.0 (200) Pendent 90 6.2 Yes
16.8 (240) Pendent 63 4.3 Yes
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 40 2.8 No
35 10.7 40 12.2 No
16.8 (240) Pendent 52 3.6 No
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 25 1.7 No
45 13.7 14.0 (200) Pendent 90 6.2 Yes
16.8 (240) Pendent 63 4.3 Yes
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 40 2.8 No
40 12.2 45 13.7 16.8 (240) Pendent 63 4.3 Yes
22.4 (320) Pendent 40 2.8 No
25.2 (360) Pendent 40 2.8 No
ESFR protection as defined shall not apply to the following:
  1. Rack storage involving solid shelves
  2. Rack storage involving combustible, open-top cartons or containers
ESFR sprinkler systems shall be designed such that the minimum operating pressure is not less than that indicated in Table 16.3.3.1 for type of storage, commodity, storage height, and building height involved.
The design area shall consist of the most hydraulically demanding area of 12 sprinklers, consisting of four sprinklers on each of three branch lines.
Where required by Table 16.3.3.1, one level of K-8.0 (115) or K-11.2 (160) quick-response, ordinary-temperature in-rack sprinklers shall be installed at the tier level closest to but not exceeding one-half of the maximum storage height.
In-rack sprinkler hydraulic design criteria shall be the most hydraulically remote eight sprinklers at 60 gpm (227 L/min).
In-rack sprinklers shall be located at the intersection of the longitudinal and transverse flue space.
Horizontal spacing shall not be permitted to exceed 5 ft (1.5 m) intervals.
The minimum of 6 in. (152 mm) vertical clear space shall be maintained between the sprinkler deflectors and the top of a tier of storage.
In-rack sprinklers shall be located at an intersection of transverse and longitudinal flues while not exceeding the maximum spacing rules.
Where distances between transverse flues exceed the maximum allowable distances, sprinklers shall be installed at the intersection of the transverse and longitudinal flues, and additional sprinklers shall be installed between transverse flues to meet the maximum distance rules.
Where no transverse flues exist, in-rack sprinklers shall not exceed the maximum spacing rules.
Where high-expansion foam systems are used for storage over 25 ft (7.6 m) high up to and including 35 ft (10.7 m) high, they shall be used in combination with ceiling sprinklers.
The maximum submergence time for the high-expansion foam shall be 5 minutes for Class I, Class II, or Class III commodities and 4 minutes for Class IV commodities.
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