Why In-Rack
Sprinklers?
Tom Multer
Vice President, Product Technology
The Reliable Automatic Sprinkler Co., Inc.
As an industry, we have spent the last 30
years trying to eliminate in-rack sprinklers.
Are they coming back?
Higher buildings using automated
storage and retrieval systems
More exposed plastic storage
.
Lower water demands by using
horizontal in-rack barriers.
Using K- 360 ECs as in-rack sprinklers
Fire Protection
Research Foundation:
Project for Rack
Storage of Exposed
Expanded Group A
Plastics
Outside the scope of
NFPA 13
Ceiling sprinklers
with vertical barriers @
4.8 m intervals
 Testing carried
out at
Underwriters
Laboratories
(UL)
 Standard fuel
package for EEP
tests using
polystyrene
meat trays.
Rack Storage of
Exposed Expanded Group A Plastics
Ceiling Height = 12.2 m
Storage Height = 10.7 m
10 mm Plywood Horizontal Barrier at 6.1 m
Ceiling Sprinklers
K-16.8 (240), 100°C ESFR @ 3.4 bar
In-Rack Sprinklers
K-25.2 (360)EC, 100°C Pendent @ 2.1 bar
Reliable
Model
N252 EC
Pendent
Patented
•K-360
•UL Listed, FM approved as a ceiling
application sprinkler
• 100°C version was used for all testing
The Model N252 EC Pendent Sprinkler is a component of the
N-Rack-EC™ Fire Protection System – Patent Pending
Minimum:
100mm clearance above commodity
50mm deflector distance below beam
Target
Array
4.2 m
Spray Pattern @ 2.1 bar
1.2 m
aisle width
10 mm
plywood
barrier at
6.1 m
level
N252 EC Sprinklers
Centered in Longitudinal Flue and Centered
Between Rack Uprights = 2.5 m on center.
The horizontal barrier was left open at the rack
uprights and no sprinklers are installed in the
transverse flue or at the face of the racks.
Results:
Opened one (1)
sprinkler at the
ceiling @ 1 minute/2
seconds
3.4 bar and 830 L/pm
Opened two (2)
sprinklers in the rack
@ 49 and 52 seconds
2.1 bar and 520 L/pm
each or 1040 L/pm total
Before
After
N-252 EC
with
Horizontal
Barrier
After
K-25 ESFR
with
Vertical
Barriers
Proposed Design
Temp
bar
L/pm
per spr
No. of
sprs
calculated
System
Demand in
L/pm
100°
3.4
450
12
5400+
In-Rack
Temp
bar
L/pm
per spr
No. of
sprs
calculated
System
Demand in
L/pm
N-252 EC
Pendent
100°
2.1
520
3
1560+
Ceiling
K-16.8 ESFR
For comparison: Actual water demands will be higher based upon hydraulic calculations.
The in-rack sprinkler demand would not be added to the ceiling
demand because of the horizontal barrier. The system demand
would be the ceiling demand at 5400+ L/pm
Existing Ceiling Sprinkler Design (FM) for Exposed
Expanded Plastics Stored in Open Racks with
12.2 m ceiling and 10.7 m of storage
Proposed
bar
K-16.8 ESFR &
N252 EC In-Rack
3.4
FM DS 8-9
bar
K-25.2
ESFR
5.2
L/pm
per spr
450
No. of sprs
calculated
Hose
Stream in
L/pm
Total System
Demand in
L/pm
12
950
6350+
L/pm
per spr
830
No. of sprs
calculated
Hose
Stream in
L/pm
Total System
Demand in
L/pm
20
1900
18,500+
2 hours
For comparison: Actual water demands will be higher based upon hydraulic calculations.
Proposed Design (NFPA 13 -2016) for
Exposed Expanded Plastics Stored in Open
Racks using Vertical Barriers at 16’ Intervals
12.2 m ceiling and 10.7 m of storage
Proposed
bar
K-16.8 ESFR &
N252 EC In-Rack
3.4
NFPA 13
bar
K-25.2
ESFR
4.1
L/pm
per spr
520
No. of sprs
calculated
Hose
Stream in
L/pm
Total System
Demand in
L/pm
12
950
6350+
L/pm
per spr
740
No. of sprs
calculated
Hose
Stream in
L/pm
Total System
Demand in
L/pm
15
950
12,050+
For comparison: Actual water demands will be higher based upon hydraulic calculations.
Second Phase of Testing
Cartoned Unexpanded, Group A Plastics
Primary Goals:
• To reduce the number of in-rack sprinklers when
compared to standard in-rack schemes and to reduce
water demands.
• To have a significant reduction of water demand for
buildings up to 14.6 m high that can currently be
protected by ceiling-only sprinklers.
• Protect buildings higher than 14.6 m with low water
demands.
• Retrofit existing facilities, where the storage
commodities or methods of storage have changed,
without changing the existing ceiling sprinklers and/or
increasing water flows or pressures.
To Date: Four Additional Fire Tests
Test 2 with Cartoned Unexpanded Plastics
Objective:
By using a horizontal barrier at 9.1 m, the total water demand and
pressure would be lower than existing ceiling-only sprinkler
designs. Also to protect buildings higher than 14.6 m with one
level of in-rack sprinklers.
Test 2
Ceiling Height
14.6 m
Storage Height
13.1 m on double row racks
Horizontal Barrier
1 at the 9.1 m level
Ignition Point
At upright- face (aisle)
Ceiling Sprinklers
N 252 EC pendent @ 18.2 m² and 2.1 bar
In-Rack Sprinklers
N 252 EC 100° pendent @ 2.1 bar
Ceiling Spr. Operated
1 @ 3:01 minutes
2 - 1st @ 2:53 2nd @ 2:59
67° C
In-Rack Spr. Operated
Peak Steel Temp – Ceil.
Proposed Design for Cartoned Unexpanded Plastics Stored in
Racks up to and potentially over 14.6 m with Horizontal
Barriers at the 9.1 m level
Ceiling
bar
L/pm
per spr
No. of
sprs .
calculated
System
Demand in
L/pm
N-252 EC Pendent @
18.2 m²/spr
2.1
520
6
3120+
The ceiling sprinkler design is based upon NFPA 13 and FM Global
requirements for 9.1 m high ceilings with ceiling-only sprinkler protection.
In-Rack
N-252 EC
Pendent
bar
L/pm
per spr
No. of
sprs .
calculated
System
Demand in
L/pm
2.1
520
3
1560+
For comparison: Actual water demands will be higher based upon hydraulic calculations.
The in-rack sprinkler demand would not be added to the ceiling demand because
of the horizontal barrier. The total system demand would be the ceiling demand at
3120+ L/pm
Current UL Listings for 13.7 m High Buildings-Class 4/Group A Plastics
Sprinkler demand
Hose stream demand
Total demand
K22/K 25 ESFR @ 9.3 m²
Proposed Design N252 EC @ 18.2 m²
6440+ L/pm/7240+ L/pm
3120+ L/pm
950 L/pm
950 L/pm
8390+ L/pm/8190+ L/pm
4070+ L/pm
Current UL Listings for 14.6 m High Buildings-Class 4/Group A Plastics
Sprinkler demand
Hose stream demand
Total demand
K22/K 25 ESFR @ 9.3 m²
Proposed Design N252 EC @ 18.2 m²
7550+ L/pm/8100+ L/pm
3120+ L/pm
950 L/pm
950 L/pm
8500+ L/pm/9050+ L/pm
4070+ L/pm
Future Protection for 14.6 m+ High Buildings- Class 4/Group A Plastics
K22/K 25 ESFR
Proposed Design - N252 EC
Sprinkler demand
NA
3120+ L/pm
Hose stream demand
NA
950 L/pm
Total demand
NA
4070+ L/pm
The Future of Storage Protection
Tests 3, 4, & 5
24.4 m/36.4 m
18.3 m/27.3 m
12.2 m/18.2 m
6.1 m/9.1 m
Test 3 with Cartoned Unexpanded Plastics
Objective:
By using multiple horizontal barriers at 6.1 m intervals, high bay
buildings may be protected with fewer in-rack sprinklers. No
face sprinklers and no sprinklers in transverse flues.
Test 3
Ceiling Height
14.6 m
Storage Height
13.1 m on double row racks
Horizontal Barrier
2 – 6.1 m level & 12.2 m level
Ignition Point
Offset in Transverse Flue
Ceiling Sprinklers
N 252 EC pendent @ 18.2 m² and 0 psi
In-Rack Sprinklers
N 252 EC 100° pendent @ 2.1 bar
Ceiling Spr. Operated
3 – 1st @ 20:40 last @ 21:15
5 - 1st @ 1:13 in 6.1 m level
1st in 12.2 m level @ 13:40
235° C
In-Rack Spr. Operated
Peak Steel Temp – Ceil.
Testing with a Continuous
Barrier Across the Uprights
Tests 1, 2, & 3
Tests 4 & 5
Test 4 with Cartoned Unexpanded Plastics
Objective:
By using multiple continuous horizontal barriers at 6.1 intervals,
high bay buildings may be protected with fewer in-rack
sprinklers. No face sprinklers and no sprinklers in transverse
flues. Fires may be contained between barriers with no
horizontal spread.
Test 4
Ceiling Height
14.6 m
Storage Height
13.1 m on double row racks
Horizontal Barrier
2 – 6.1 m level & 12.2 m level
Ignition Point
Offset in Transverse Flue
Ceiling Sprinklers
N 252 EC pendent @ 18.2 m² and 0 psi
In-Rack Sprinklers
N 252 EC 100° pendent @ 2.1 bar
Ceiling Spr. Operated
None
In-Rack Spr. Operated
Peak Steel Temp – Ceil.
4 – 6.1 m level only
1st @ 1:26 4th @ 1:36
28° C
Test 5 with Cartoned Unexpanded Plastics
Objective:
By using multiple continuous horizontal barriers at 9.1 m intervals,
high bay buildings may be protected with fewer in-rack
sprinklers. No face sprinklers and no sprinklers in transverse
flues. Fires may be contained between barriers with no
horizontal spread.
Test 5
Ceiling Height
14.6 m
Storage Height
13.1 m on double row racks
Horizontal Barrier
1 – 9.1 m level
Ignition Point
Offset in Transverse Flue
Ceiling Sprinklers
N 252 EC pendent @ 18.2 m² and 0 psi
In-Rack Sprinklers
N 252 EC 100° pendent @ 2.1 bar
Ceiling Spr. Operated
None
In-Rack Spr. Operated
Peak Steel Temp – Ceil.
3 -9.1 m level
1st @ 1.14
28° C
3rd @ 1.15
View at 9.1 m Level Horizontal Barrier
In Conclusion:
For storage of exposed expanded plastics in
double row, open framed racks:
By installing a horizontal barrier at the 6.1 m
level with the Model N252 EC Pendent, used
as in-rack sprinklers, buildings up to 12.2 m
high will have lower water demands than
using ceiling-only sprinkler protection.
For storage of cartoned unexpanded plastics in
double row, open framed racks:
By installing a horizontal barrier at the 9.1 m
level with the Model N252 EC Pendent, used
as in-rack sprinklers, buildings up to 14.6 m
high will have lower water demands than
using ceiling-only sprinkler protection.
Retrofit applications where storage
commodities or methods of storage have
changed, adding a horizontal barrier or
barriers with the Model N252 EC Pendent,
used as in-rack sprinklers, may eliminate
changing ceiling sprinklers or water supplies.
For storage of cartoned unexpanded plastics in
double row, open framed racks:
By installing continuous horizontal barriers at 6.1 m to
9.1 m levels with the Model N252 EC Pendent, used as
in-rack sprinklers, buildings over 14.6 m high may be
protected while reducing the number of sprinklers
required by current in-rack schemes. Fires may be
contained between barriers with no horizontal spread.
Retrofit applications of high bay buildings where storage
commodities or methods of storage have changed,
adding continuous horizontal barriers with the Model
N252 EC Pendent, used as in-rack sprinklers, may
eliminate changing ceiling sprinklers or water supplies
while greatly reducing the quantity of in-rack
sprinklers.