Proteccion de Almacenaje de Plasticos

7/30/2019 Proteccion de Almacenaje de Plasticos

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Sprinkler Protection Criteria for Exposed Expanded Group A PlasticsProject Summary

BackgroundNFPA 13, Standard for the Installation of Sprinkler Systems, has limited informationregarding protection criteria for Exposed Expanded Group A plastic commodity storedon racks. There is an important present need for protection criteria for this type ofcommodity, since it presents a significant fire hazard and is stored in many warehouse

and retail buildings.

At the 2008 meeting of the FoundationsAutomatic Sprinkler Research PlanningCouncil, this topic was identified as an area where additional research is needed toinform provisions of NFPA 13. At the Councils 2011 meeting, the topic was identified ator near the top of the priority list of projects with a particular focus on results needed forthe next edition of the Standard.

Although there is a broad range of criteria needed, the particular focus of this projectwas rack storage of this commodity with protection solutions which do not involve inrack sprinklers, to improve the flexibility of this storage protection configuration.

Previous testing by Viking Corporation in Europe showed successful performance withceiling only K19 sprinkler protection at 40-50 psi design pressure for 40 foot storage ofactual mixed commodity (candles, foam slabs, cardboard boxes) in a non standard rackconfiguration with vertical barriers interspersed in the rack at approximately 20 foot oncenter.

Research ObjectiveTo develop cost effective sprinkler protection criteria for rack storage of exposed

expanded Group A plastic commodity with a particular focus on ceiling only protection.


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Project ExecutionA Project Technical Panel was formed and met four times during 2012 to develop aproposed test plan and review and revise that plan during the course of its conduct.

Project Technical Panel

Ken Linder, Swiss Re (Chair NFPA

Sprinkler System Discharge Criteria

Technical Committee)

Rich Pehrson, (International Fire

Marshals Association)

Jason Huczek, Southwest Research

Institute

John Denhardt, Strickland Fire

Protection

Steve Wolin, Code Consultants, Inc.Matt Klaus, NFPA Staff Liaison

Project ContractorUnderwriters Laboratories DanSteppan, Kerry Bell

Project Sponsor Representatives

IKEA - Tom Pedersen, Jan Lagerblad

Viking Sprinkler Scott Franson

Reliable Sprinkler Tom Multer

Tyco Fire and Building Products

James Golinveaux

XL Insurance Pete Willse

Property Insurance Research Group -

Rich Gallagher (Zurich Insurance)

P&G - Christina FrancisTarget Karen Rebman

Aon Insurance Tom Lentz

Discussion of Results

In total, six full scale tests were conducted with various combinations of ceiling andcommodity height, horizontal transverse flue space blocking, placement and type ofvertical barriers, sprinkler type, and ignition location. All tests used standard exposedexpanded Group A plastic commodity (expanded polystyrene meat trays) stored in


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plastic bags and resting on two-way entry, hardwood pallets). With the horizontalblocking of transverse flue spaces, the length of the main storage arrays was extendedbeyond the normal 32 ft. to obtain useful data relative to evaluating the potential forhorizontal travel of fire to the extremities of the test array. Table 1 summarizes the testparameters and the test results. A fully detailed test report has been prepared by UL

LLC and is available on the Foundations website. Innovative testing methods wereused to conserve the costly standard expanded plastics commodity.

Two of the six tests conducted met the pre established criteria of prevention of firespread to the end of the array or to the target array. (All of the tests met the preestablished criteria for peak steel temperature above the ignition source.) The followingobservations were made during the test program which may inform future work:

Vertical barriers in the commodity had a significant positive impact by limiting thehorizontal spread of fire along the commodity array. Both non combustible andcombustible (3/8 plywood) barriers demonstrated the ability to maintain their

integrity during the fire test series. The fire in the main test bay breached at leastone of the vertical barriers placed closest to the ignition location in each test bytravelling around the barrier at the aisle face where the commodity extendedapproximately 4 inches beyond the face of the barriers. However, the horizontalprogress of the fire down the length of the racks was delayed by the barriers andhelped enable the sprinkler system to control the fire spread.

The horizontal blocking of transverse flue spaces reduced the ability of thesprinkler system to effectively discharge water into the blocked flue spaces andlimit the horizontal travel of fire.

8 foot aisle widths were a significant factor in the prevention of aisle jump in thefirst four tests; a wider aisle width (as used in the previous European test series)

may have a further positive effect. In the tests where aisle jump occurred, thesprinkler activation pattern contributed to fire spread across the aisle.

Other variables observed to significantly impact the performance of the protectionscheme include:

o sprinkler type which influenced penetration in the commodity andactivation sequence;

o ceiling height and clearance to the commodity which did not influenceactuation time significantly but did influence water penetration and numberof operated sprinklers; and

o ignition location relative to the sprinklers, which significantly influencedactivation pattern and fire control.

Potential Future StudiesFuture protection options which may be explored are lower storage and ceiling heights,larger aisle widths, reduced transverse flue space blocking, a more limited set ofexposed expanded Group A plastic commodities, and other protection schemesincluding the option of a single horizontal barrier within the rack with enhanced in-racksprinkler protection at one level immediately below the barrier.


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Table 1. Test Parameters and Results

FIRE TEST NUMBER Test 1 Test 2 Test 3 Test 4 Test 5 Test 6

Test Date July 9, 2012 July 13, 2012 July 18, 2012 July 25, 2012 October 31, 2012 November 8, 2012

Test Parameters

Storage Type Double Row Rack

Commodity TypeExposed Expanded Group A Plastic(Bagged Meat Trays on Hardwood Pallets)

Pallet Type 2 way entry, stringer, hardwood

Vertical Barriers

16 ft. on

center -Main Array

(Non-combustible)

16 ft. on

center - Main

Array (Non-combustible)

16 ft. on

center - Main

Array (Non-combustible)

20 ft. on center

- Main Array

(Non-combustible)

24 ft. on center

- Main Array

(3/8 in.plywood)

16 ft. on center -

Main Array

(3/8 in.plywood)

Horizontal Blocking of Transverse

Flues in Main Array (non-

combustible)

18 flues inside

vertical

barriers

12 flues inside

vertical

barriers None

at uprights

72 flues - None

at the uprights

and vertical

barriers

60 flues - None

at the uprights

and vertical

barriers

98 flues - None

at the uprights

and vertical

barriers

60 flues - None at

the uprights and

vertical barriers

Length of Main Storage Array, ft. 32 32 56 68 56 56

Nominal Storage Height, ft. 20 20 35 30 40 30

Ceiling Height, ft. 40 40 40 35 45 40

Nominal Clearance, ft. 20 20 5 5 5 10

Aisle Width, ft. 8

Ignition Location Between 2 Sprinklers (offset) Under 1 Sprinkler (offset)

Sprinkler Systems Ceiling Only (no in-rack sprinklers)

Sprinkler Orientation Pendent

Deflector to Ceiling, in. 14Sprinkler Spacing, sprinkler by

branchline ft. by ft.10 by 10

Temperature Rating, F 212 214 214 212 214 214

Sprinkler Type ESFRNominal Sprinkler Discharge

Coefficient K, gpm/psig 0.522.4 25.2 25.2 16.8 25.2 25.2

Nominal Discharge Density,

gpm/ft21.58 1.95 1.95 1.19 - 0.99 1.95 1.95

Nominal Discharge Pressure, psig 50 60 60

50 psig first6 sprinklers then 35

psig for remainder

of operatingsprinklers

60 60

Test Results

Length of Test, minutes 31 31 31 31 31 31

First Sprinkler Operation Time,

min:sec0:39 0:44 0:52 0:47 0:47 0:48

Last Sprinkler Operation Time,

min:sec8:23 3:21 1:45 2:44 1:39 4:35

Number of Operated Sprinklers 12 6 10 16 18 11

Peak Gas Temperature at Ceiling Above

Ignition, F564 558 1138 1163 1002 241

Maximum 1 minute Average Gas

Temperature at Ceiling Above Ignition, F255 220 353 496 489 151

Peak Steel Temperature at Ceiling Above

Ignition, F126 119 145 164 160 129

Maximum 1 minute Average Steel

Temperature at Ceiling Above Ignition, F124 117 141 164 156 127

Ignition Time of Target Array,

minutes:secondsNone None None None

1:01

(North Target)

1:27

(South Target)

Fire Travel to Extremities of Test

Array

Yes(East and

West end of

Main)

Yes(West end of

Main)

No No

Yes(North Target Array

Burned Through toExtremities)

Yes(South Target Array

Burned Through toExtremities)

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Proteccion de Almacenaje de Plasticos