Heads up: There are no amended sections in this chapter.
The requirements of Chapter 12 shall apply unless modified by this chapter.
Plastic automotive components and associated packaging material shall be permitted to be protected in accordance with Table 20.2.

Table 20.2 ESFR Sprinkler Design Criteria K-25.2 (360) for Portable Racks (Closed Arraya) Without Solid Shelves Containing Automotive Components

Commodity Maximum Storage Height Maximum Ceiling/Roof Height Type of System Maximum Sprinkler Spacingb Number of Design Sprinklers by Minimum Operating Pressurec Maximum Deflector Distance Below Ceilingd Hose Stream Allowance Water Supply Duration (hours)
ft m ft m ft2 m2 psi bar in. mm gpm L/min
Automotive components and associated packaging material 25 7.6 35 10.7 Wet 100 9.3 16 at 37 psi 16 at 2.5 bar 18 457 500 1900 2
aPortable rack array shall be tightly nested without any flue spaces.
bSprinkler spacing can exceed 100 ft2 (9.3 m2 ) where sprinklers are listed for larger spacing.
cSystem hydraulic design shall also be capable of delivering a discharge density of 0.60 gpm/ft2 (24.4 mm/m) over the most hydraulically remote 4000 ft2 (372 m2) area.
dMaximum deflector distance below ceiling shall be permitted to exceed 18 in. (456 mm) where sprinklers are listed for greater distances.
A wet pipe system designed to meet two separate design points — 0.6 gpm/ft2 (24.4 mm/min) density over 2000 ft2 (186 m2) and 0.7 gpm/ft2 (28.5 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted to protect single- and double-row slatted shelf racks when the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. Shelves shall be either open shelving or slatted using a 2 in. (50 mm) thick by maximum 6 in. (152 mm) wide slat held in place by spacers that maintain a minimum 2 in. (50 mm) opening between each slat.
  3. There shall be no slatted shelf levels in the rack above nominal 12 ft (3.66 m) level. Wire mesh (greater than 50 percent opening) shall be permitted for shelf levels above 12 ft (3.66 m).
  4. A single level of solid shelving (31/2 ft × 8 ft 3 in.) (1.07 m × 2.51 m) shall be permissible at an elevation of not more than 5 ft (1.52 m).
  5. Perforated metal (open area of 40 percent or more) shall be permitted over either the open shelving or the slatted shelves up to the 60 in. (1.52 m) level.
  6. Other than what is allowed in this section, solid plywood or similar materials shall not be placed on the slatted shelves.
  7. Solid displays shall be permissible, provided that all flues are maintained and only one display is installed per bay.
  8. Maximum roof height shall be 30 ft (9.14 m) in the protected area.
  9. Maximum storage height shall be 22 ft (6.71 m).
  10. Aisle widths shall be a minimum of 8 ft (2.44 m).
  11. Minimum transverse flue spaces of 3 in. every 10 ft (76 mm every 3.05 m) horizontally shall be provided.
  12. Minimum longitudinal flue spaces of 6 in. (152 mm) shall be provided for double-row racks.
  13. Storage in the aisle shall be permissible, provided the aisle storage is no more than 4 ft (1.22 m) high and a minimum clear aisle of 4 ft (1.22 m) is maintained.
A wet pipe system designed to meet two separate design points — 0.425 gpm/ft2 (17.3 mm/min) density over 2000 ft2 (186 m2) and 0.50 gpm/ft2 (20.4 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted in solid steel cantilever-style retail shelving racks (gondola racks) when the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. The storage height shall not exceed 12 ft (3.66 m).
  3. The ceiling height shall not exceed 22 ft (6.71 m) in the protected area.
  4. Gondola rack structure shall not exceed 48 in. (1.22 m) in aggregate depth or 78 in. (1.99 m) in height.
  5. A minimum aisle of 5 ft (1.52 m) between storage shall be maintained.
  6. Rack lengths shall be no more than 70 ft (21.3 m).
A wet system designed to meet two separate design points — 0.425 gpm/ft2 (17.3 mm/min) density over 2000 ft2 (186 m2) and 0.50 gpm/ft2 (20.4 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted in solid steel cantilever-style retail shelving racks (gondola racks) when the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. Storage height shall not exceed 15 ft (4.57 m).
  3. Ceiling height shall not exceed 25 ft (7.62 m) in the protected area.
  4. Gondola rack structure shall not exceed 60 in. (1.52 m) in aggregate depth or 8 ft (2.44 m) in height.
  5. A perforated metal deck at the 8 ft (2.44 m) level shall be permissible with storage placed on top with or without flue spaces to a maximum height from floor of 15 ft (4.57 m).
  6. Rack lengths shall not exceed 70 ft (21.3 m).
  7. A minimum aisle space of 6 ft (1.83 m) shall be provided.
A wet pipe system designed to meet two separate design points — 0.45 gpm/ft2 (17.3 mm/min) density over 2000 ft2 (186 m2) and 0.55 gpm/ft2 (22.4 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted without the use of in-rack sprinklers when the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. Storage height shall not exceed 15 ft (4.57 m).
  3. Ceiling height shall not exceed 25 ft (7.62 m).
  4. Shelving structure shall not exceed 48 in. (1.22 mm) aggregate depth or 12 ft (3.66 m) in height.
  5. Shelving shall be permitted to be made of solid particleboard.
  6. A minimum aisle space of 3 ft (914 mm) shall be maintained.
  7. Shelving length shall be a maximum of 70 ft (21.3 m).
A wet pipe system designed to meet two separate design points — 0.38 gpm/ft2 (15.5 mm/min) density over 2000 ft2 (186 m2) and 0.45 gpm/ft2 (17.3 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted without the use of in-rack sprinklers in steel retail sales floor shelving racks where the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. Storage height shall not exceed 14 ft (4.27 m).
  3. Ceiling height shall not exceed 20 ft (6.1 m).
  4. Solid metal shelving shall be permissible up to the 72 in. (1.83 mm) level and wire shelving shall be permissible up to the 10 ft (3.05 m) level.
  5. The solid metal shelving shall not exceed 66 in. (1.68 m) in aggregate depth with a 6 in. (152 mm) longitudinal flue between two 30 in. (762 mm) deep shelves.
  6. A minimum aisle space of 5 ft (1.52 m) shall be maintained.
  7. A minimum longitudinal flue of 6 in. (152 mm) shall be maintained.
  8. Rack length shall be a maximum of 70 ft (21.3 m).
A wet pipe system designed to meet two separate design points — 0.49 gpm/ft2 (20 mm/min) density over 2000 ft2 (186 m2) and 0.55 gpm/ft2 (22.4 mm/min) density for the four hydraulically most demanding sprinklers with 500 gpm (1900 L/min) hose stream allowance for a 2-hour duration — shall be permitted without the use of in-rack sprinklers in retail solid shelved steel rack structure when the following conditions are met:
  1. An extended coverage sprinkler with a nominal K-factor of K-25.2 (360) listed for storage occupancies shall be provided.
  2. Storage height shall not exceed 16.5 ft (5.03 m).
  3. Ceiling height shall not exceed 22 ft (6.71 m).
  4. Shelving structure shall not exceed 51 in. (1.3 m) aggregate depth or 148 in. (3.76 m) in height.
  5. The intersection of perpendicular steel racks shall be permissible as long as no storage is placed within the void space at the junction of the racks.
  6. The top shelf shall be wire mesh.
  7. A minimum aisle width of 4 ft (1.22 m) shall be maintained between shelf units and other displays.
A sprinkler system with K-25.2 (360) ESFR sprinklers operating at a minimum pressure of 15 psi (1 bar) shall be permitted to protect single- and double-row racks with solid displays without the use of in-rack sprinklers in retail sales floor where the following conditions are met:
  1. Storage height shall not exceed 20 ft (6.1 m).
  2. Solid veneered particleboard/plywood displays shall be permissible, provided that all flues are maintained and only one display is installed per bay.
  3. A single display shall be permitted to have one or two solid horizontal or slanted members, and a solid back.
  4. Maximum roof height shall be 30 ft (9.14 m) in the protected area.
  5. Aisle widths shall be a minimum of 6 ft (1.8 m).
  6. Minimum transverse flue spaces of 3 in. every 10 ft (76 mm every 3.05 m) horizontally shall be provided.
  7. Minimum longitudinal flue spaces of 6 in. (152 mm) shall be provided for double-row racks.
Protection of Baled Cotton Storage.
The requirements of Chapter 12 shall apply unless modified by this chapter.
The total water supply available shall be sufficient to provide the recommended sprinkler discharge density over the area to be protected, plus a minimum of 500 gpm (1900 L/min) for hose streams.
Water supplies shall be capable of supplying the total demand for sprinklers and hose streams for not less than 2 hours.
Control Mode Density/Area Sprinkler Protection Criteria for Baled Cotton Storage.
For tiered or rack storage up to a nominal 15 ft (4.6 m) in height, sprinkler discharge densities and areas of application shall be in accordance with Table 20.4.2.1.

Table 20.4.2.1 Baled Cotton Storage Up to and Including 15 ft (4.6 m)

System Type Discharge Density (gpm/ft2) per Area (ft2)
Tiered Storage Rack Storage Untiered Storage
Wet 0.25/3000 0.33/3000 0.15/3000
Dry 0.25/3900 0.33/3900 0.15/3900
Where roof or ceiling heights would prohibit storage above a nominal 10 ft (3.1 m), the sprinkler discharge density shall be permitted to be reduced by 20 percent of that indicated in Table 20.4.2.1 but shall not be reduced to less than 0.15 gpm/ft2 (6.1 mm/min).
Carton records storage shall be permitted to be protected in accordance with the succeeding subsections of Section 20.5.
Carton records storage shall be permitted to be supported on shelving that is a minimum of 50 percent open from approved flue space to approved flue space.
Transverse flue spaces of a nominal 6 in. (152.4 mm) width shall be located at each rack upright.
Rack uprights shall be installed on a maximum of 10 ft 6 in. (3.2 m) centers.
Longitudinal flues shall not be required.
The storage rack structure for carton records storage shall consist of either of the following:
  1. A single-row rack not greater than 72 in. (1.8 m) deep
  2. Double-row racks having a total depth of not greater than 102 in. (2.6 m) aisle to aisle
Each storage rack shall be separated from other storage racks by aisles that are not less than 30 in. (0.75 m) and not more than 36 in. (0.9 m) in width.
Aisles used for ingress and egress shall be permitted to be up to 44 in. (1.1 m) wide when solid decking is used.
Catwalk aisles between racks shall be constructed of open metal grating that is at least 50 percent open.
Catwalk aisles at the ends of racks shall be permitted to be constructed of solid materials.
Catwalks shall be installed at a maximum of 12 ft (3.7 m) apart vertically.
Cartoned record storage in racks with access utilizing catwalks shall be protected in accordance with this subsection.
The design criteria for the ceiling sprinkler system shall be in accordance with Table 20.5.6.2.

Table 20.5.6.2 Ceiling Sprinkler Design Criteria for Carton Record Storage

Up to 25 ft High Storage Over 25 ft High Storage
Ordinary Temperature High Temperature Ordinary Temperature High Temperature
Density (gpm/ft2) 0.33 0.29 0.3 0.4
Area (ft2) 2000 2000 2000 2000
Hose Allowance (gpm) 500 500 500 500
Duration (hours) 2 2 2 2

For SI units, 1 gpm/ft2 = 40.746 mm/min; 1 ft2 = 0.09 m2; 1 gpm = 3.785 L/min.

Ceiling sprinklers spaced to cover a maximum of 100 ft2 (9.3 m2) shall be standard-response spray sprinklers with K-factors per Section 12.6.
Intermediate-level sprinklers shall be installed at each catwalk level in accordance with 20.5.6.3.1 through 20.5.6.3.4 and shall be quick-response, ordinary temperature, nominal K-5.6 (80), K-8.0 (115), or K-11.2 (160).
Intermediate-level sprinklers shall be installed in the center ±4 in. (102 mm) of each aisle below each catwalk level.
Intermediate-level sprinklers shall be installed a minimum 6 in. (150 mm) above the top of storage.
Sprinklers shall be supplied from the in-rack sprinkler system.
Spacing of sprinklers within the aisles shall be located so as to align with the transverse flues and the center of the storage unit when staggered and shall not exceed 10 ft 6 in. (3.2 m) on center.
Sprinklers installed below each catwalk level shall be staggered vertically and horizontally. [See Figure A.20.5.6.3.5(a) and Figure A.20.5.6.3.5(b).]
In-rack sprinklers shall be installed in the transverse flues at each catwalk level and shall be staggered vertically.
Sprinklers installed in the transverse flues shall be located not less than 18 in. (0.46 m) but not greater than 24 in. (0.61 m) from the face of the rack.
In-rack sprinklers shall be installed a minimum 6 in. (150 mm) above the top of storage.
Transverse flue sprinklers shall be quick-response, ordinary temperature, nominal K-5.6 (80), K-8.0 (115), or K-11.2 (160) and installed in accordance with Figure A.20.5.6.3.5(a) and Figure A.20.5.6.3.5(b).
For multiple-level catwalk systems, a minimum of 10 sprinklers, five on each of the top two levels, shall be calculated with a minimum flow rate of 30 gpm (113.6 L/min) per sprinkler. Calculated sprinklers shall be the hydraulically most demanding on each level.
For single-level catwalks, a minimum of six sprinklers shall be calculated with a minimum flow rate at 30 gpm (113.6 L/min) per sprinkler. Calculated sprinklers shall be the hydraulically most demanding.
The in-rack sprinkler system shall be balanced in with the ceiling system.
Compact storage modules up to 8 ft (2.44 m) high storing commodities consisting of paper files, magazines, books, and similar documents in folders and miscellaneous supplies with no more than 5 percent plastics shall be permitted to be classified as light hazard.
The top of the compact storage module shall be at least 18 in. (457 mm) below the sprinkler deflector.
Sprinklers shall be ordinary temperature, quick- response, standard spray upright or pendent.
The compact storage module shall be provided with minimum solid steel 24 gauge metal longitudinal barriers installed every third carriage.
Solid 24 gauge metal transverse barriers shall be spaced not more than 4 ft (1.2 m) apart.
Compact storage module sizes shall not exceed 250 ft2 (23.2 m2).
The size of a module shall be defined as the area of compact storage bound by the length of the carriages times the distance between longitudinal barriers or to the outward edge of a fixed storage unit in the module, including the width of the aisle in the module.
The lengths of the carriages shall be measured to the end of the carriages enclosed by solid metal transverse panels and separated by a minimum 28 in. (0.7 m) aisle to a storage unit perpendicular to the carriage.
The requirements in this section shall be permitted to apply to ceiling-only sprinkler protection of paper products, including paper files, magazines, books, and similar paper documents in corrugated containers either closed or open top, to include corrugated totes, with no more than 5 percent plastics stored in mobile shelving units greater than 12 ft (3.7 m) and up to 34 ft (10.4 m) high and up to 30 shelving units (storage tiers) high, when the shelving unit structure meets all of the requirements in 20.7.3.
High bay record storage shall be permitted to be fixed in place when meeting the limitations of 20.7.1 and 20.7.3.
A wet pipe sprinkler system with nominal K-25.2 (360) ESFR sprinklers operating at a minimum of 40 psi (2.8 bar) shall be provided. The shelving units shall be subject to the following limitations:
  1. Back-to-back storage shelving units each no greater than 36 in. (914 mm) deep separated by longitudinal flue space not less than 6 in. (152 mm) wide.
  2. Solid steel shelving units not exceeding 54 in. (1372 mm) wide separated by steel barriers mechanically fastened to upright steel framing that forms a transverse flue space not less than 3 in. (76 mm) wide.
  3. Upright steel framing not completely blocking transverse flue space between adjacent shelving units.
  4. Noncombustible shelving backstops and side shelf supports, also referred to as side box guides, projecting not less than 3 in. (76 mm) above the shelves and that prevent stored commodities from encroaching into transverse and longitudinal flue spaces.
  5. Solid steel shelving not greater than 18 in. (457 mm) on centers vertically.
  6. Solid steel tops over top shelving units except at tops of transverse and longitudinal flue spaces.
  7. Open-ended, hollow tubular steel vertical (upright) shelving columns at top of shelving system.
  8. Shelving system framing and power tracks not exceeding 3 in. (76 mm) in width and not less than 1 ft (0.305 m) on centers and not less than 6 in. (152 mm) below sprinkler deflectors.
  9. Minimum clearance of 36 in. (914 mm) above top solid steel cover over top storage shelf to the sprinkler deflector.
  10. Mobile shelving systems arranged to shift automatically to a uniform nominal 6 in. (152 mm) clearance clear space between mobile carriages supporting back-to-back shelving units. Systems shall be arranged to initiate the shifting 60 seconds after activation of ceiling-mounted smoke detectors or upon sprinkler flow, whichever is first. Shelving system carriage electrical motors shall be listed and integral to the mobile carriage systems for normal functions and shall not be required to have emergency power back-up.
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