Short Answer
The full title of FM DS 8-23 is Rolled Nonwoven Fabric Storage; it deals with indoor storage of rolled nonwoven fabrics. Its three defining decisions are: dry-pipe systems are not used, on-end floor storage calls for standard-response high-temperature sprinklers, and the highloft and fiberfill group is treated as a separate, heavier hazard.
Identity and Scope of the Data Sheet
The copy used here is dated January 2015 and has 31 pages (cover, PDF p.1). Under the scope section (Section 1.0), the data sheet gives fire protection guidance for various rolled nonwoven fabrics that are solid-piled or palletized, stored on end or on side, on the floor or in racks (PDF p.3).
Under the Appendix A definition, a nonwoven fabric is a product with a low to medium density fibrous web structure resembling tissue, medium-weight paper or felt; common fibers are wood pulp, rayon, polyester and polypropylene (PDF p.30). The same glossary defines the storage arrays: a closed array is an on-end arrangement with pile spacing of less than 4 in. (100 mm) in all directions; an open array has spacing of 4 in. (100 mm) or more in all directions; a standard array is contiguous in one direction and spaced 4 in. (100 mm) or more in the other.
The EN side is covered in the EN 12845 Annex G nonwoven synthetic fabric article; the focus here is FM.
Construction, Ceiling and Water Damage
Section 2.1.1.1 requires the storage facility to be built in line with the relevant FM data sheets, including the 1-series. Section 2.1.1.4 requires rack loads to account for the extra load from fire water collected or absorbed by the stored commodity, the weight of water-filled in-rack sprinkler piping, and natural hazard loads (PDF p.3).
Other construction decisions:
- Steel protection. When sprinkler systems are installed per this data sheet, fire protection of roof steel is not needed. For steel columns within the storage array, one sidewall sprinkler at the 15 ft (4.6 m) level, directed at one face of the column and discharging 30 gpm (115 L/min), is enough (Section 2.1.2, PDF p.3).
- Suspended ceiling. If a suspended ceiling is installed to provide suitable clearance above the storage, it must withstand temperatures above 1000°F (538°C) for up to 10 minutes and an uplift pressure of at least 3 lb/ft2 (0.14 kPa) (Section 2.1.3.1, PDF p.3).
- Venting. FM's recommended protection assumes there are no roof vents or draft curtains; where permanent heat and smoke vents exist, they should be arranged for manual operation (Section 2.1.4, PDF p.4).
- Water damage. Section 2.1.5.1 asks for skids, pallets, channels, floor drains or similar measures to reduce water damage (PDF p.4).
Sprinkler System Type and Ceiling Sprinklers
The sharpest rule in this data sheet is about system type. Under Section 2.2.2.1, ceiling systems designed for at least 15 sprinklers or 1,500 ft2 (140 m2) can be wet-pipe or preaction; preaction systems must be single-interlocked and arranged so they count as equivalent to a wet system for design. For smaller designs only wet-pipe systems are recommended. Section 2.2.2.2 says dry-pipe systems should not be used for this storage (PDF p.4).
For ceiling-level storage sprinklers, Section 2.2.3 sets the following (PDF p.5):
| Item | Rule | Reference |
|---|---|---|
| Approval | Only FM Approved sprinklers listed in the Approval Guide under Storage Sprinklers (Ceiling-Level) | 2.2.3.1 |
| K-factor range | K11.2 (K160) to K25.2 (K360) | 2.2.3.2 |
| Minimum operating pressure | 7 psi (0.5 bar) | 2.2.3.3 |
| Extent of the design | In mixed occupancies, at least 15 ft (4.5 m) beyond all edges of the storage, or to the wall | 2.2.3.4 |
| Intermediate heights | No interpolation in Tables 1-4 for intermediate storage heights | 2.2.3.5 |
For K-factor families see the site's K-factor table, and for setting up the hydraulic calculation the DS 3-0 hydraulics fundamentals article; Section 2.2.1.7 itself refers to DS 3-0 for the calculation.
Floor and Rack Protection Tables
On-end floor storage. Table 1 gives the design for on-end floor storage in closed or standard arrays with a ceiling height of up to 30 ft (9.1 m), and calls for standard-response 280°F (140°C) pendent or upright sprinklers (DS 8-23, Table 1, PDF p.6).
| Maximum storage height | K11.2 (K160) | K14.0 (K200) | K16.8 (K240) | K25.2 (K360) |
|---|---|---|---|---|
| 5 ft (1.5 m) | 20 @ 7 psi (0.5 bar) | 20 @ 7 (0.5) | 20 @ 7 (0.5) | 20 @ 7 (0.5) |
| 10 ft (3.0 m) | 15 @ 75 psi (5.2 bar) | 15 @ 48 (3.3) | 15 @ 33 (2.3) | 15 @ 15 (1.0) |
| 16 ft (4.9 m) | 20 @ 75 (5.2) | 20 @ 48 (3.3) | 20 @ 33 (2.3) | 20 @ 15 (1.0) |
| 20 ft (6.1 m) | 25 @ 75 (5.2) | 25 @ 48 (3.3) | 25 @ 33 (2.3) | 25 @ 15 (1.0) |
Two lines under the table complete the design: a hose allowance of 250 gpm (950 L/min) and a water supply duration of 2 hours. The same note states that rolls of nonwoven fabric enclosed in corrugated cartons including both ends, or wrapped including both ends in at least four layers of 40 lb/1000 ft2 (19.6 kg/100 m2) heavy kraft paper, can be protected as unexpanded plastic per DS 8-9 (PDF p.6).
Section 2.2.6.1 also explains why this table calls for standard-response, high-temperature sprinklers: on-end floor arrangements have continuous flue spaces, which can produce very strong fire plumes able to overwhelm quick-response sprinklers (PDF p.6). The flue space concept is defined in the flue space glossary article.
Rack or palletized storage. Table 2 gives a design with quick-response 160°F (70°C) storage sprinklers for 35 ft (10.7 m) storage under a ceiling of up to 40 ft (12.2 m), wet system, pendent sprinklers: 12 @ 75 psi (5.2 bar) for K14.0 (K200), 12 @ 52 psi (3.6 bar) for K16.8 (K240), 12 @ 45 psi (3.1 bar) for K22.4 (K320) and 12 @ 40 psi (2.8 bar) for K25.2 (K360). The hose allowance is 250 gpm (950 L/min) and the water supply duration 1 hour (DS 8-23, Table 2, PDF p.7).
Section 2.2.7.3.1 limits the scope of this table: Table 2 applies to rolled nonwoven fabrics made of polypropylene, rayon and polyethylene; it is not used for nonwovens such as fiberfill, highloft and batting or dry-laid pulp (PDF p.6). For double-row and multiple-row racks with standard-response sprinklers, Tables 3 and 4 are used; they give the minimum ceiling density together with in-rack sprinkler arrangement and barrier options (DS 8-23, Table 3, PDF p.8-9; Table 4, PDF p.11).
In-Rack Sprinklers
The basic rules of Section 2.2.4 (PDF p.5):
- In-rack sprinklers are chosen from FM Approved products listed in the Approval Guide under Storage Sprinklers (In-Racks) (2.2.4.2).
- Nominal 160°F (70°C) sprinklers are used in all in-rack installations (2.2.4.3).
- For K14.0 (K200) and smaller, a quick-response listing is required; larger K-factors can be quick or standard response (2.2.4.4).
- The storage height above the top level of in-rack sprinklers must not exceed 10 ft (3.0 m) (2.2.4.5).
- The water demands of the ceiling and in-rack systems are balanced at the point where the two systems connect (2.2.4.6).
- In-rack sprinklers are placed within the rack array; for a single-row rack 12 in. (300 mm) from a wall they can be outside, in which case they must be within 6 in. (150 mm) horizontally of the rack structure and offset no more than 3 in. (75 mm) from the transverse flue space intersection they are meant to protect (2.2.4.7.1).
Highloft, Fiberfill and the Loft Factor
Section 2.2.5 calls for nominal 280°F (140°C) ceiling-level sprinklers for highloft nonwoven fabric, and says fiberfill, highloft and batting should be stored in a 1-hour rated cutoff area with ceiling protection able to deliver 0.60 gpm/ft2 (24 mm/min) over the whole area. As alternatives it defines three options (PDF p.5-6):
- Storage in a detached, low-value building, with or without sprinklers.
- 500 ft2 (46 m2) piles separated by 20 ft (6.1 m) in every direction; storage height 10 ft (3 m), maximum ceiling height 30 ft (9.1 m) and ceiling protection of 0.60 gpm/ft2 (24 mm/min) over 3,000 ft2 (280 m2).
- 500 ft2 (46 m2) piles separated by 20 ft (6.1 m) in every direction; storage height 5 ft (1.5 m), maximum ceiling height 30 ft (9.1 m) and ceiling protection of 0.30 gpm/ft2 (12 mm/min) over 2,000 ft2 (185 m2).
Whether a roll falls into this group is decided by the loft factor of Appendix C.1. The formula uses roll length, outside and inside diameter, density, roll weight and core weight; a roll loft factor of 25 or more indicates batting, fiberfill or highloft material, and the number is a value FM derived for comparison purposes (PDF p.31). For the design density concept see the design density glossary article.
Field Note
The data sheet's test data explains why it is so conservative with this material. Under Section 3.1, in intermediate-scale tests of on-end floor storage 20 ft (6.1 m) and 18 ft (5.5 m) high, K11.2 (K160) sprinklers discharging 0.60 gpm/ft2 (24.5 mm/min) could not control the fire; in a full-scale test 21 ft (6.4 m) high, K14.0 (K200) quick-response 165°F (74°C) pendent sprinklers operating at 50 psi (3.4 bar) did not achieve adequate suppression (PDF p.29).
The same section contains another practical warning: if protection is inadequate, exposed building steel can quickly reach temperatures at which it may collapse, and excessive steel deflection can break the sprinkler piping, taking protection out of service exactly when it is most needed (PDF p.29). The interpolation ban in Section 2.2.3.5 works in the same direction: for an intermediate storage height no value can be derived between table rows; the next higher row is taken.
Checklist
- Confirmed that the material falls under the nonwoven fabric definition and which fiber type it is
- Loft factor calculated; if 25 or more, the highloft/fiberfill regime applied (Appendix C.1)
- System type chosen as wet or single-interlocked preaction; dry-pipe ruled out (Section 2.2.2.2)
- Standard-response 280°F (140°C) sprinklers chosen for on-end floor storage (Table 1)
- If quick-response 160°F (70°C) is chosen in racks, confirmed that the material is within the scope of Table 2
- No interpolation for intermediate storage heights (Section 2.2.3.5)
- No more than 10 ft (3.0 m) of storage left above the in-rack sprinklers (Section 2.2.4.5)
- Ceiling and in-rack water demands balanced at the connection point (Section 2.2.4.6)
- Hose allowance and duration taken from the table used (Table 1: 250 gpm, 2 hours; Table 2: 250 gpm, 1 hour)
- Where steel column protection or a suspended ceiling is used, the criteria of Sections 2.1.2 and 2.1.3 met
Frequently Asked Questions
What material does DS 8-23 cover?
Under Section 1.0 it covers indoor storage of various types of rolled nonwoven fabrics: solid-piled or palletized, on end or on side, on the floor or in racks. Under the Appendix A definition, a nonwoven fabric is a product with a low to medium density web structure of fibers such as wood pulp, rayon, polyester and polypropylene.
Can a dry-pipe system be used for rolled nonwoven fabric storage?
No. Section 2.2.2.2 states plainly that dry-pipe sprinkler systems should not be used to protect rolled nonwoven fabric storage. Under Section 2.2.2.1, ceiling systems designed for at least 15 sprinklers or 1,500 ft2 (140 m2) can be wet or preaction; for smaller designs only a wet system is recommended.
Why are highloft and fiberfill treated separately?
According to the test data in Section 3.1, with batting, fiberfill and highloft materials, ceiling-only K11.2 (K160) sprinklers operating at 75 psi (5.2 bar) could not control a fire in a 16 ft (4.9 m) high rack array. Section 2.2.5 therefore introduces separate measures for these materials, such as 280°F (140°C) ceiling sprinklers and a 1-hour cutoff area.
What is the loft factor?
It is a comparison number defined in Appendix C.1, calculated from roll length, outside and inside diameter, density, roll weight and core weight. A roll loft factor of 25 or more indicates that the material is batting, fiberfill or highloft, and protection is chosen for that group.
References
- FM Property Loss Prevention Data Sheet 8-23, Rolled Nonwoven Fabric Storage, January 2015. Sections used: Section 1.0 (PDF p.3), 2.1.1-2.1.3 (p.3), 2.1.4-2.1.6 (p.4), 2.2.1-2.2.2 (p.4), 2.2.3-2.2.5 (p.5), Table 1 and 2.2.6 (p.6), Table 2 and 2.2.7 (p.7), Table 3 (p.8), 2.3 and 3.1-3.2 (p.29), Appendix A (p.30), Appendix C.1 (p.31).
- FM Global, Property Loss Prevention Data Sheets: https://www.fmglobal.com/research-and-resources/fm-global-data-sheets
- selvi.org, EN 12845 Annex G: Nonwoven Synthetic Fabric
- selvi.org, FM Global DS 3-0: Hydraulics Fundamentals
- selvi.org, What is flue space?
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Download MEP Calc on the App StoreFM Property Loss Prevention Data Sheet 8-23, Rolled Nonwoven Fabric Storage, January 2015; clause, table and page references are listed under References. General information only: the current edition governs, and design must be carried out by a qualified engineer.