UL and the UL logo are trademarks of UL LLC © 2014 Alternative Sprinkler System Designs for Storage...

UL and the UL logo are trademarks of UL LLC © 2014

Alternative Sprinkler System Designs for Storage Protection

Kerry M. Bell

Principal Engineer

Fire Sprinkler and Pump Equipment

UL LLC

20 May 2014

Fire Sprinkler International 2014

COPYRIGHT © 2014 UL LLC. ALL RIGHTS RESERVED. THIS DOCUMENT MAY NOT BE REPRODUCED OR DISTRIBUTED WITHOUT PERMISSION OF UNDERWRITERS LABORATORIES INC.

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Overview • Historical development of new sprinkler

technology for use in accordance with the NFPA 13, Standard for the Installation of Sprinkler Systems

• Discussion on the new Chapter 21 in the 2013 Edition of NFPA 13 that provides the opportunity for more cost efficient storage sprinkler system designs to be developed.

• Information and data from large scale fire testing that highlights the importance of having appropriate large scale fire test data to evaluate/validate the ability of the sprinkler to provide the desired level of protection for a storage facility.


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NFPA 13 and New Sprinkler Technology • For decades, NFPA 13 has encouraged the

development of new sprinkler technology.

• 1973 Edition of NFPA 13

4-1.1.3 Special Sprinklers may be installed with larger protection areas or distances between sprinklers than are specified in Sections 4-2 and 4-5 when such installations are made in accordance with approvals or listings of a nationally recognized testing laboratory.


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NFPA 13 and New Sprinkler Technology • Over the years, this text has been revised to

provide additional guidance and clarity related to the development of new sprinkler technology as illustrated in the 2013 Edition of NFPA 13 as follows:8.4.8 Special Sprinklers.8.4.8.1* Special sprinklers that are intended for the protection of specific hazards or construction features shall be permitted where such devices have been evaluated and listed for performance under the following conditions:(1) Fire tests related to the intended hazard(2) Distribution of the spray pattern with respect to wetting of floors and walls(3) Distribution of the spray pattern with respect to obstructions(4) Evaluation of the thermal sensitivity of the sprinkler(5) Performance under horizontal or sloped ceilings(6) Area of design(7) Allowable clearance to ceilings

Text Source: NFPA 13 2013


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NFPA 13 and New Sprinkler Technology

Non-Storage Sprinkler Technology

• Extended coverage light hazard sprinklers

• Extended coverage ordinary hazard sprinklers

• Attic sprinklers

• Combustible concealed space sprinklers


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Ceiling Sprinkler Types Currently Referenced in NFPA 13 for Use in Storage Applications at Discharge Densities of Greater than 13.9 mm/min (0.34 gpm/sq. ft.)

No.Nominal K-factor Style

Initial

Availability Type Protection

1 160(11.2) Pendent Early 1990s CMDA Fire Control

2 160(11.2) Upright Early 1990s CMDA Fire Control

3 200(14.0) Pendent 1996 CMDA Fire Control

4 240(16.8) Pendent 1997 CMDA Fire Control

5 240(16.8) Upright 1997 CMDA Fire Control

6 360(25.2) EC Pendent 2006 CMDA Fire Control

7 360(25.2) EC Upright 2001 CMDA Fire Control

8 160(11.2) Upright 1981 CMSA (Large Drop) Fire Control

9 240(16.8) Upright 1997 CMSA Fire Control

10 280(19.6) Pendent 2008 CMSA Fire Control

11 360(25.2) EC Pendent 2010 CMSA Fire Control

12 360(25.2) EC Upright 2011 CMSA Fire Control


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Ceiling Sprinkler Types Currently Referenced in NFPA 13 for Use in Storage Applications at Discharge Densities of Greater than 13.9 mm/min (0.34 gpm/sq. ft.)

No.Nominal K-factor Style

Initial

Availability Type Protection

13 200(14.0) Pendent 1987 ESFR Fire Suppression

14 200(14.0) Upright 1999 ESFR Fire Suppression


16 240(16.8) Upright 2002 ESFR Fire Suppression




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New Chapter 21 of NFPA 13 - 2013

General

21.1.1 Sprinklers intended to protect storage fire risks shall be permitted to be installed using water supply design criteria that are different from the design criteria specified for the sprinklers described in Chapters 12 through 19 when specifically listed for such use within the limitations described in this chapter.

Text Source: NFPA 13 – 2013


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21.1.6 A series of large-scale fire tests involving challenging test scenarios that address the range of variables associated with the intended application of the sprinkler shall be conducted to evaluate the ability of the sprinkler to protect storage fire risks that are representative of those described in themanufacturer’s installation and design parameter instructions and referenced in the listing.



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For a sprinkler system design to be covered under Chapter 21, it must be validated through large-scale fire testing--typically 3 or 4 large scale fire tests. Test parameters that are to be considered during the test series include:

• Ignition location • Maximum storage height • Sprinkler spacing • Sprinkler temperature rating • Ceiling height • Clearance from storage to ceiling• Sprinkler distance below ceiling• Minimum operating pressure of sprinkler • Highest commodity hazard• Storage arrangement type• Aisle width


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Text source: NFPA 13 – 2013

Sprinkler System Design Based Upon Test Results

If all four tests yield acceptable results then the design is based on:

• Worst-case test result during test series increased by 50% (safety factor), and

• Minimum of 12 sprinklers for standard coverage type sprinklers [Nominal area = ~111 m2 (~1200 ft2)]

• Minimum of 8 sprinklers for EC sprinklers on 3.7 m x 3.7 m (12 ft x 12 ft) spacing [Nominal area = ~111 m2 (~1200 ft2)]

• Minimum of 6 sprinklers for EC sprinklers on 4.3 m x 4.3 m (14 ft

x 14 ft) spacing [Nominal area = ~111 m2 (~1200 ft2)] • The resulting demand area shall not be less than 71 m2 (768 ft²).


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Additional Installation and Design Criteria


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Additional Installation and Design Criteria

• Minimum obstruction criteria is based upon based upon the number of sprinklers included in the sprinkler design and correlates to existing criteria in NFPA 13 for CMDA, CMSA, Extended Coverage and ESFR sprinklers.

• A smaller number of sprinklers in the design results in more stringent obstruction criteria to reduce the potential for excessive sprinkler operations during a fire.

• As an option to the prescribed obstruction criteria described in Chapter 21, large scale fire testing with obstructions can be conducted to validate alternative obstruction criteria for a specific sprinkler.


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21.1.7 The manufacturer’s installation and design parameter instructions for these sprinklers shall specify in a standardizedmanner the end-use limitations and sprinkler system design criteria including at least the following:(1) Commodity or commodities to be protected(2) Storage arrangements allowed(3) Installation guidelines including obstruction and ceiling construction limitations(4) Maximum ceiling and storage heights with associated minimum operating pressures and number of sprinklers required to be included in the hydraulic calculation(5) Hose stream allowance and duration



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Comparison of Sprinkler Design Requirements in Chapters 12- 19 vs. Chapter 21 of NFPA 13 -2013

Sprinkler TypeNo. of Design

SprinklersHose Allowance,

L/min (gpm) Duration, min.

CMDA* 20 or more 1900 (500) 120 or more

EC-CMDA* 11 or more 1900 (500) 120 or more

CMSA 15 or more 1900 (500) 90 or more

ESFR 12 950 (250) 60

Chapters 12 – 19

Sprinkler TypeNo. of Design

SprinklersHose Allowance,

L/min (gpm) Duration, min.

CMSA & ESFR 12 950 (250) 60

EC (3.7 m x 3.7 m) 8 950 (250) 60

EC (4.3 m x 4.3 m) 6 950 (250) 60

Lowest Demand Permitted in Chapter 21

*Ceiling-only sprinkler options


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Sprinklers Currently Referenced in Chapter 21 of NFPA 13 -2013

Sprinkler Type

NominalK-factor,

lpm/ bar1/2

(gpm/psig 0.5)

Commodity Storage

Maximum Storage and

Ceiling Height, m (ft.)

Coverage Area,m by m (ft. by ft.)

EC-CMSA

360 (25.2)Pendent and

Upright

Palletized, solid pile and open

rack storage of commodities up

to cartoned, unexpanded

Group A plastic

9.1/10.7 (30/35)

3.7 by 3.7(12 by 12)

and 4.3 by 4.3(14 by 14)

Note: NFPA 13 provides detailed information on the allowed coverage areas, number of design sprinklers, minimum design pressures, hose stream allowances and water supply duration for both the pendent and upright EC-CMSA sprinklers referenced in Chapter 21.

• Sprinklers are permitted to be listed (certified) in accordance with Chapter 21 without the design criteria specifically referenced in this chapter.


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Example of Fire Test Series for Sprinkler Protecting 10.7 m (35 ft) Rack Storage Under a 12.2 m (40 ft) Ceiling

Test Parameters Test 1 Test 2 Test 3 Test 4

Storage TypeDouble Row

RackDouble Row

RackDouble Row

RackDouble Row

RackNominal Storage Height, m (ft) 9.1 (30) 10.7 (35) 9.1 (30) 6.1 (20)

Nominal Ceiling Height, m (ft) 12.2 (40)

Minimum distance from

sprinkler deflector to commodity

12.2 (40) 12.2 (40)

Nominal Deflector Distance to Ceiling, cm (in)

Within 30.5 (12)Maximum

specified by manufacturer

Maximum specified by

manufacturer


manufacturerSprinkler Temperature Rating Minimum Maximum Minimum Minimum

Sprinkler Spacing, m (ft)3 by 3

(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)

Nominal Discharge Pressure, kPa (psig) Minimum design Minimum design Minimum design Minimum design

Ignition location Under one Between 4Between two on same branch line

Between two on same branch line

Test Duration, min 30 30 30 30

Test 1 – Investigates ability of sprinkler to effectively attack a fire originating in a location beneath a sprinkler.


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RackDouble Row

RackDouble Row

RackDouble Row





12.2 (40) 12.2 (40)





manufacturer




(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)





Test 2 – Investigates ability of sprinkler to effectively attack a fire originating between four sprinklers with the highest storage height and smallest sprinkler clearance to top of commodity clearance which generally creates the greatest HRR from the fire prior to sprinkler operation.


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RackDouble Row

RackDouble Row

RackDouble Row





12.2 (40) 12.2 (40)





manufacturer




(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)





Test 3 – Investigates ability of the sprinkler to attack a fire originating in an an area between two sprinklers where the sprinkler discharge is impacted by the sprinkler frame arms and obstructed by the supply pipe if it is an upright style sprinkler.


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RackDouble Row

RackDouble Row

RackDouble Row





12.2 (40) 12.2 (40)





manufacturer




(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)3 by 3

(10 by 10)





Test 4 – Investigates ability of the sprinkler to attack a fire with a large clearance between the sprinkler deflector and top of storage.


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Why is it Important to Conduct Large Scale Fire Testing Using Multiple Ignition Locations?

Due to the unique discharge characteristics of each sprinkler design, the weakest level of protection with respect to location of fire origin relative to the sprinkler can vary depending on the sprinkler’s construction characteristics:

• The water discharge characteristics throughout a sprinkler’s coverage area are not uniform.

• The overlap of water spray from adjacent sprinklers varies within the sprinkler coverage area.

• Water discharged from a sprinkler is obstructed by the sprinkler frame as well as the piping for upright style sprinklers.

• Response time of the sprinkler can vary depending upon ignition location.


Actual Delivered Density (ADD) Testing -- A Dynamic Water Distribution Test for Storage Type Sprinklers

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ADD testing is a useful tool to investigate a sprinkler’s discharge characteristics; however, this testing is conducted with open sprinklers which does not investigate the potential for sprinkler skipping to occur.


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NFPA 13-2013 Revisions Based Upon Large Scale Fire Test Data

• For nominal K=200 (14.0) Pendent ESFR sprinklers, 2013 Edition of NFPA 13 was revised to limit the use of these sprinklers in new installations to a maximum ceiling height of 10.7m (35 ft) rather than the previously referenced 12.2 m (40 ft) ceilings.

• Larger K-factor ESFR sprinklers can still be used for ceiling heights of 12.2 m (40 ft.) and 13.7 m (45 ft).


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Fire Test Results of Nominal K=200 (14) ESFR Pendent Sprinkler 6.1 m (20 ft) Clearance Comparison of UL and FM Storage vs. Non-Storage Sprinklers

FIRE TEST NUMBER Test 1 Test 2TEST PARAMETERS

Storage Type Double Row Rack Double Row Rack

Commodity TypeCartoned,

Unexpanded Group A Plastic

Cartoned, Unexpanded Group A Plastic

Nominal Storage Height, m(ft) 6.1 (20) 6.1 (20)Nominal Ceiling Height, m(ft) 12.2 (40) 12.2 (40)

Aisle Width, m(ft) 1.2 (4) 1.2 (4)Ignition Location Offset Between 2 Offset Between 2

Temperature Rating, °C(°F) 74 (165) 74 (165)

Deflector to Ceiling, cm (in) 36 (14) 36 (14)

Nominal Sprinkler Discharge Coefficient K, 200 lpm/ bar1/2 (gpm/psig 0.5)

200 (14) 200 (14)

Nominal Discharge Pressure, bar (psig) 5.2 (75)

6.9 (100) for first 4 operated sprinklers, 5.2

(75) when more than four sprinklers have operated

Sprinkler Spacing, m (ft) 3 by 3 (10 by 10) 3 by 3 (10 by 10)TEST RESULTS

First Sprinkler Operation, min:sec 1:28 0:55Last Sprinkler Operation, min:sec 6:06 6:20

Number of Operated Sprinklers 17 18 Maximum I Minute Average Steel Temperature

Above Ignition, °C(°F)81 (178) 83 (181)

Fire Spread Across the Aisle Yes Yes


Illustration of Sprinkler Skipping – Nominal K=200(14.0) ESFR Sprinkler with Cartoned, Unexpanded Group A Plastic Commodity and a 12.2 m(40 ft) Ceiling Height

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Illustration of Sprinkler Skipping – Test 3 from FPRF Exposed Expanded Group A Plastics Project Using ESFR Sprinklers

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Summary

• Since the 1970’s, NFPA 13 has included text that encourages the development of new sprinkler technology.

• The new Chapter 21 of NFPA 13-2013 provides another opportunity to develop more cost efficient sprinkler protection for storage facilities.

• It is important for the Chapter 21 sprinkler system design criteria to be properly validated with large scale fire testing that takes into account multiple ignition locations and the potential for sprinkler skipping to occur.

• For sprinkler system designs not referenced in NFPA 13, users, designers and approval authorities can request to review the large scale fire test data that supports a sprinkler system design covered by Chapter 21 of NFPA 13.

UL and the UL logo are trademarks of UL LLC © 2014 Alternative Sprinkler System Designs for Storage...

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Transcript of UL and the UL logo are trademarks of UL LLC © 2014 Alternative Sprinkler System Designs for Storage...