27-

EXTRA LARGE ORIFICE (ELO) SPRINKLERS:AN OVERVIEW OF FULL-SCALE FIRE TEST PERFORMANCE

Joan M.A. TroupFactory Mutual Research Corporation

1151 Boston-Providence TurnpikeNorwood, MA 02062

ABSTRACT

The Extra Large Orifice (ELO) sprinkler was developed for use in lieu of standard, ½ in.(12.7 mm) and 17/32 in. (13.5 m) orifice, sprinklers, particularly for protection of high piledstorage in warehouses. Because of the ELO sprinkler’s large, nominal 0.64 in. (16.3 mm)orifice, less pressure is required to achieve a given discharge density. Reduced pressurescan be helpful in compensating for weak water supplies and thereby may eliminate theneed for in-rack sprinklers, pumps and/or on-site water storage. A research program wasdeveloped to provide a performance-based evaluation, using full-scale fire testing, toverify the ELO sprinkler’s effectiveness. Data from duplicate tests conducted with standardsprinklers and the first ELO model demonstrate improved performance with the ELO. Acomparison of test data from subsequent models shows similar results.

INTRODUCTION

SummaryThis paper addresses an improvement in auto-matic sprinkler technology, specifically, thedevelopment and performance testing of theExtra Large Orifice (ELO) Sprinkler. The ELOsprinkler is intended for use as a replacementfor standard, 1/2 in. (12.7 mm) and 17/32 in.(13.5 mm) orifice, sprinklers. Because of the ELOsprinkler’s large, nominal 0.64 in. (16.3 mm), ori-fice, less pressure is required to achieve a givendischarge density (i.e., compared to standardsprinklers); and, thereby, the ELO provides moreefficient and cost-effective protection, particu-larly for high piled storage in warehouses.

Factory Mutual Research Corporation (FMRC)developed a research program to provide a per-formance-based evaluation, using full-scale firetesting, to verify the protection performance ofthe ELO sprinkler.’,’ These tests became thebasis for FM-Approval performance criteria3 fora new sprinkler category and for protection andinstallation guidelines.4 Data from baseline testsconducted with standard sprinklers and dupli-cate tests with the first ELO sprinkler modeldemonstrate improved performance with theELO. Also, a comparison of test data from subse-quent ELO models from five sprinkler manufac-turers shows similar good results.

A review of these research programs allows fora better understanding of how a new product isevaluated, so that prior to reaching the market,appropriate design, quality and protection appli-cation will be assured.

Definition: Extra Large Orifice (ELO)SprinklerThe ELO sprinkler is a &dquo;Control Mode&dquo; standardspray sprinkler with a nominal 0.64 in.(16.3 mm) orifice and K-factor range of 11.0 to11.5 gal/min/(psif/2 [15.8 to 16.6 dm3/min/(kPar/2]. It is not considered a &dquo;Large-Drop&dquo;sprinkler, despite its similar orifice size. And,unlike the Large-Drop sprinkler, the &dquo;Density-Area&dquo; Sprinkler System Design Method that isused for standard sprinklers applies; Large-Dropdesign criteria are not acceptable. The ELOsprinkler is intended for use in facilities whereprotection usually would be provided by standardsprinklers, but, the available water supply isinadequate or discharge pressure is low. Sincethe ELO provides design densities using lowerdischarge pressures compared to pressurerequirements using standard sprinklers, its usemay eliminate the need for a pump, on-site water

storage, or in-rack sprinklers. Costs associatedwith their installation and subsequent mainte-nance costs could be saved. Also, the resultingincreased water drop size of the ELO enhancespenetration through the fire plume.

28-

Table 1 compares major characteristics of theELO and other sprinklers. (Restrictions on sprin-kler spacings and coverage areas are includedin system installation guidelines, such as thosefound in FM Loss Prevention Data Sheets.’) Aswould be expected, due to differences in orificesize and deflector style, these sprinklers exhibitvariations in spray patterns and distributioncharacteristics. Of relevance herein are the dif-ferences in minimum discharge pressurerequirements between ELO and Large-Dropsprinklers and between ELO and standard sprin-klers. Because of the ELO’s large orifice, the dis-charge pressure can be reduced to about 25%of that required for a 1/2 in. (12.7 mm) orificesprinkler and to about 52% of that required fora 17/32 in. (13.5 mm) orifice sprinkler, to achievethe same discharge density. These significantdifferences in pressure requirements will behighlighted in the comparative fire tests con-ducted with standard and ELO sprinklers thatare discussed below.

BackgroundThe ELO sprinkler is not a completely newdesign. Currently available models are similar inappearance to several manufacturers’ standard

sprinkler models, except for the required pintleon the deflector (Figure 1). Variations of this typeof sprinkler had been under development and

Figure 1. Extra Large Orifice (ELO) Sprinkler Models.

some models have been in use for over 10 years.But, there were no FM-Approved models or evenan FM-approval category to evaluate ELO sprin-klers. Also, the models listed by UnderwritersLaboratories had restricted use; specifically,they were excluded from application under theNational Fire Protection Association’s storageprotection standards, NFPA 231 & 231C.5

In 1992, a sprinkler manufacturer, Central- Sprinkler Company, contracted with FMRC todevelop a research program to determine appro-priate uses for their &dquo;ELO&dquo; sprinkler with theintent of achieving FM-Approval. A team wasassembled from the three Divisions of FMRC to

Table 1. Sprinkler Characteristics

NOTE: *In early 1998, FMRC designated the following four automatic sprinkler classifications:Control Mode(Density/Area), which includes standard 1/2 in. and 17/32 in. and ELO;Control Mode (Specific Application), which includes Large-Drop; Suppression Mode (EarlySuppression Fast Response), which includes K-14.0 (ESFR); and, Residential. Thesedesignations will be incorporated into future revisions of FM Loss Prevention Data Sheetsand Approval Standards.

-29-

assess the sprinkler’s performance and deter-mine potential benefits and limitations. TheResearch Division designed and executed a full-scale fire test program to verify sprinkler protec-tion performance. The Approvals Division con-ducted mechanical and hydraulic performanceevaluations (required of all sprinklers to achieveFM-Approval). The Standards Division devel-oped installation and protection guidelines. Thiscooperative effort culminated in a new FM-Approval Standard3. The first FM-ApprovedELO model arrived in 1993.

FULL-SCALE FIRE TESTPROGRAMS

Full-scale fire testing using realistic large-scalewarehouse storage configurations has been dem-onstrated to be a definitive method for evaluatingthe performance of automatic sprinkler protec-tion systems. The extensive FMRC database,amassed from over 40 years of such testing, wassearched to develop a program using compara-tive tests to evaluate the ELO sprinkler. Full-scale fire test data will be presented from thefollowing three programs:

Performance Verification Tests (ELOVersus Standard Sprinklers)The initial research programl consisted of threefull-scale fire tests (Table 2) to verify the perfor-mance of the ELO sprinkler. The following testswere repeats of tests that had been conductedwith protection provided by standard sprinklers,except for the substitution of ELO sprinklers:(1) Palletized Storage of Cartoned Group A Unex-panded Plastic Commodity; (2) Rack Storage ofCartoned Group A Unexpanded Plastic Commod-ity ; and (3) Rack Storage of Class 2 Commodity.

Supplemental Tests (ELO Sprinklers)Good results achieved in the initial performanceverification tests prompted a request from Cen-tral Sprinkler Company for another researchprogram.’ The purpose was to further define theELO sprinkler’s application and to explore thefeasibility of reducing system design arearequirements. Two additional full-scale tests(Table 3) were conducted with two different rack

storage arrays loaded with a Cartoned Group AUnexpanded Plastic Commodity.

FM-Approval Performance CriteriaTests (Various ELO Models)To demonstrate the performance of six differentELO models, data from the three full-scale firetests that are required to be successfully exe-cuted to achieve FM-Approval are presented. Thetests were selected from the above two test pro-grams : Test 1 and Test 3 (Table 2) and Test 4(Table 3).

GEPIERAL TEST CONDITION

Factory Mutual Test CenterThe full-scale fire tests were performed at theFM Test Center in West Glocester, Rhode Island.The 50,000 ft2 (4645 m2) fire test building hasa continuous ceiling and contains two primary3,600 ft2 (334 m2) test sites, 30 ft (9.1 m) and 60 ft(18.2 m) high. These test sites may be adaptedto provide other ceiling heights by erecting plat-forms on the floor. For the ELO performanceevaluation, specific tests were conducted under30 ft (9.1 m) and 25 ft (7.6 m) high ceilings.

Automatic Sprinkler ProtectionThe sprinkler systems in the fire test buildingcan reproduce various protection conditions.Sprinkler piping accommodates both upright andpendent models at various spacings incorporat-ing over 1,000 sprinkler fitting positions. TheELO sprinklers were installed in 2 in. (5 cm)diameter piping located just below the test siteceiling. The distances between the ceiling andan upright model’s deflector and fusible elementwere approximately 7 in. (18 cm) and 8 in.(20 cm), respectively. All sprinklers used in thetests were standard response models, which havea nominal Response Time Index (RTI) value of300 ft’/2s’/2 (166 ml/2s1/2). Both 165°F (74°C) and286°F (141°C) sprinklers were used in specifictests. The constant discharge densities suppliedfor specific tests were either 0.37 or 0.60 gpm/ft2(15 or 24 mm/min). See Table 2.

Test CommoditiesThe tests were performed using two FMRC stan-dard test commodities, Plastic and Class 2.These products were developed for testing pur-poses over 25 years ago and have been acceptedby the fire protection engineering community torepresent their respective commodity classes.

-30-

Table 2. Performance Verification Test Summary (Standard Versus ELO Sprinklers)

NOTE: *Data not monitored.

They have been used extensively in full-scale tes-ting, from which current FM and NFPA storageprotection standards have been developed.

The FM Standard Plastic Test Commodityserves as a Cartoned Group A Unexpanded Plas-tic fuel. A pallet load of the product consists ofeight 21 in. (0.5 m) cube, single-wall, corrugated

paper cartons, stacked 2 x 2 X 2 on a slatteddeck hardwood pallet. Each carton contains125 empty, 16 oz (0.5 L) polystyrene cups thatare individually compartmentalized with corru-gated paper partitions.

The FM Standard Class 2 Test Commodity con-sists of two doubled-up, triwall, corrugated paper

31

Table 3. Supplemental ELO Sprinkler Fire Test Summary

cartons supported on a slatted deck hardwoodpallet. The total paper thickness is about 1 in.(2.5 cm); the outer carton’s outside dimensionsare 42 in. (1.1 m) per side. The unit contains afive-sided sheet metal liner, representing thenon-combustible contents of this Class 2 com-

modity.

Instrumentation and Ignition MethodInstrumentation installed for the tests included:

sprinklers equipped with timing mechanismsat 96 locations;

thermocouples for gas temperature measure-ment near the ceiling at 35 locations;

thermocouples embedded in a steel anglelocated at the ceiling over the ignition point;

fire plume velocity probes centered over thearrays, 4 ft (1.22 m) below the ceiling; and

heat flux gages located on target arrays oppo-site the ignition flues.

Ignition was achieved with standard FMRCigniters, 3 in. X 3 in. (8 cm X 8 cm) cylinders ofrolled cellucotton, each soaked in 4 oz (118 mL)of gasoline. The rolls were placed at floor levelin the flue spaces indicated in the test array dia-

grams (Figures 2, 5, 8 and 11). After lighting theigniters, the fires were allowed to develop natu-rally.

Test Evaluation CriteriaResults of the large-scale fire tests were judgedprimarily on the general criteria listed below. 1

-32-

Additional more specific criteria were subse-quently developed for performance evaluation offuture ELO sprinkler models governed by FM-Approval guidelines3; Table 4 includes themajor criteria.

1. Magnitude of the water demand. A maximum2000 ft’ (186 m2) design area was desired.

2. Magnitude and duration of elevated ceilinglevel gas and steel temperatures. Tempera-tures sustained at levels sufficient to endan-

ger exposed structural steel would be unac-ceptable (e.g., steel temperatures in excess of1180°F (638°C) and gas temperatures sus-tained at or above 1000°F (538°C) for morethan 7 minutes have been judged unsafe).

3. Extent of fire damage. Confinement of the firewithin the test array limits was required.

TEST DETAILS: PERFORMANCEVERIFICATION TESTS

Three full-scale fire tests that had been con-ducted with protection provided by standardsprinklers were chosen to be repeated using ELOsprinklers. Results from the previous andrepeated tests would be compared to assess theperformance of the ELO sprinklers. The out-comes of the standard sprinkler tests were con-sidered acceptable (under the criteria in effectwhen the tests were conducted), but reaching thelimits of effective protection for the tested storagesituations. These tests were chosen to challengethe ELO sprinkler’s range. Test variables incor-porated : low and high sprinkler system dischargepressures; two storage arrangements, rack andpalletized; and two commodity classes, Plasticand Class 2, representing high and low fire haz-ards. Test conditions and comparative results fol-low. See Table 2.

Test 1 Comparison: PalletizedStorage, Plastic CommodityThe first test was conducted with a 15 ft (4.6 m)

high, palletized storage arrangement of the Plas-tic commodity erected under a 25 ft (7.6 m) highceiling. Details of the storage arrangement areshown in Figure 2. Test conditions, listed inTable 2, were identical in the ELO test and previ-ous standard sprinkler test, except for the dis-charge pressures. To provide the 0.60 gpm/ft2

(24 mm/min) discharge density required to pro-tect this storage, the pressure was 19 psi(1.3 bar) with ELO sprinklers versus 36 psi(2.5 bar) with 17/32 in. (13.5 mm) sprinklers.The sprinkler operation diagram, Figure 3,shows the 16 and 24 locations that opened inthe ELO and 17/32 in. (13.5 mm) sprinkler tests,respectively. The fire damage areas outlined inFigure 4 show the significantly smaller area inthe ELO test compared to that in the 17/32 in.(13.5 mm) test. Peak and one-minute-averagetemperature data are included in Table 2 forcomparison. Measurements in the ELO test weresignificantly lower than those recorded in thestandard sprinkler test, and durations of highlevels were not sufficient to endanger exposedstructural steel.

Test 2 Comparison: Rack Storage,Plastic CommodityThe second test was conducted with a 14 ft

(4.3 m) high, double-row rack storage arrange-ment of Plastic commodity erected under a 25 ft(7.6 m) high ceiling. This rack storage test pro-vides a more severe fire challenge than the pal-letized (Test 1) arrangement. Details of the stor-age arrangement are shown in Figure 5 and testconditions are listed in Table 2. To provide the0.60 gpm/ft2 (24 mm/min) discharge densityrequired to protect this storage, the pressure was29 psi (2.0 bar) with ELO sprinklers versus55 psi (3.8 bar) with 17/32 in. (13.5 mm) sprin-klers. The sprinkler operation diagram, Figure 6,shows the 4 and 29 locations that opened in theELO and 17/32 in. (13.5 mm) sprinkler tests,respectively. The fire damage areas outlined inFigure 7 show the significantly smaller area inthe ELO test compared to that in the 17/32 in.(13.5 mm) test. Table 2 lists temperature data;as in Test 1, measurements were significantlylower in the ELO test compared to those in thestandard sprinkler test.

Test 3 Comparison: Rack Storage,Class 2 CommodityThe third test was conducted with a 19 ft (5.8 m)high, double-row rack storage arrangement ofClass 2 commodity erected under a 30 ft (9.1 m)high ceiling. This test was conducted to establishminimum discharge pressure requirements forthe ELO. Details of the storage arrangement areshown in Figure 8 and test conditions are listedin Table 2. To provide the 0.37 gpm/ft2 (15 mm/

-33

Table 4. Summary of Full-Scale Fire Tests for Approval of ELO Sprinklers

34-

Figure 3. Test 1 Sprinkler Operations (Standard VersusELO Sprinklers).

Figure 4. Test 1 Overall Fire Damage (Standard VersusELO Sprinklers).

min) discharge density required to protect thisstorage, the pressure was 11 psi (0.8 bar) withELO sprinklers versus 43 psi (3.0 bar) with1/2 in. (12.7 mm) sprinklers. The sprinkler opera-tion diagram, Figure 9, shows the 9 and18 locations that opened in the ELO and 1/2in.(12.7 mm) sprinkler tests, respectively. The firedamage areas outlined in Figure 10 show the sig-nificantly smaller area in the ELO test comparedto that in the 1/2 in. (12.7 mm) test. Table 2 liststemperature data; again, values were signifi-

cantly lower in the ELO test compared to thestandard sprinkler test.

TEST DETAILS: SUPPLEMENTALPERFORMANCE EVALUATION TESTS

Results of the three performance verificationtests were very good; in fact, they were signifi-cantly better than those for the tests using stan-dard sprinklers. These results prompted Central

-35

Figure 6. Test 2 Sprinkler Operations (Standard VersusELO Sprinklers).

Sprinkler Company to contract for anotherresearch program to explore whether it would befeasible to further define the application for theELO sprinkler. At issue were: (1) using lowerdischarge pressure for Plastics protection; and(2) reducing minimum allowable system designcoverage area requirements. For protection ofrack stored Plastics requiring a 0.60 gpm/ft2

Figure 7. Test 2 Overall Fire Damage (Standard VersusELO Sprinklers).

36-

Figure 9. Test 3 Sprinkler Operations (Standard VersusELO Sprinklers).

Figure 10. Test 3 Overall Fire Damage (Standard VersusELO Sprinklers).

37-

(24 mm/min) density, an even lower dischargepressure, 19 psi (1.3 bar), could be used if theELO sprinklers were installed on 8 ft X 10 ft

(2.4 m X 3.05 m) spacing, instead of the 29 psi(2.0 bar) required for 10 ft X 10 ft (3.05 m X3.05 m) spacing (as was used in Test 2). Also, theexcellent results of Test 2, in which only foursprinklers opened, appeared to justify reducingdesign area requirements. However, for highchallenge fires, such as those involving rack stor-age of Plastics, there was concern that at loweroperating pressures ceiling level cooling wouldbe insufficient and/or the number of sprinkleroperations would be excessive. Two additionalfull-scale fire tests (Table 3) were proposed toexplore these issues.’

Test 4 and Test 5 were conducted with double-row rack storage arrays of Plastic commodityerected under a 25 ft (7.6 m) high ceiling; detailsof the storage arrangements are shown in

Figure 11. Two different ignition locations wereused to explore the two worst-case &dquo;fire scenar-ios&dquo; identified in previous FMRC test pro-grams .1,7 Previous tests have shown worst-case

ignition location can be correlated with ceilingsprinkler location, storage height, and ceilingclearance. The two scenarios are: (1) fire startingdirectly below a sprinkler with high ceiling clear-ance (Test 4); and (2) a fire starting between twosprinklers with low ceiling clearance (Test 5). Aslisted in Table 3, conditions for both tests wereidentical, except for the storage height and igni-tion location (with respect to the sprinklers).

For Test 4, the array was 15 ft (4.6 m) high andignition was located directly below one sprinkler.Sprinkler operations and the overall fire damagearea are shown in Figure 12. Eleven sprinklersopened and fire damage was limited to the center8 ft (2.4 m) long area in the 41 ft (12.5 m) longdouble-row racks. Temperatures remained wellbelow acceptable levels (Table 3).

For Test 5, the array was 20 ft (6.1 m) high andignition was centered between two sprinklers.Sprinkler operations and the overall fire damagearea are shown in Figure 13. Six sprinklersopened and fire damage was limited to the center10 ft (3.05 m) long area in the racks. Tempera-

Figure 11. Tests 4 & 5 Rack Storage Plastic Commodity.

38-

Figure 12. Test 4 Sprinkler Operations and FireDamage.

Figure 13. Test 5 Sprinkler Operations and FireDamage.

tures remained well below acceptable levels(Table 3).

Again, good results were achieved. Concern forinadequate ceiling level cooling when low dis-charge pressure is used for protection of rackstored Plastic was alleviated, and sufficient datawere provided to justify reducing design area

requirements. For ceiling only protection with ELOsprinklers supplying a 0.60 gpmfft2 (24 mm/min)discharge density, covering Cartoned Group AUnexpanded Plastics stored up to 20 ft (6.1 m) highunder a 25 ft (7.6 m) high ceiling, current designarea requirements are: (1) 2000 ft’ (186 m2), accord-ing to FM Data Sheet 8-9 and (2) 4000 ft2 (372 m2),according to NFPA 231C 4,5

TEST RESULTS: FM-APPROVALPERFORMANCE CRITERIA TESTS

Three full-scale fire tests were selected from thetwo test programs (presented above) for inclusionin the FM-Approval Standard3 covering the eval-uation of future ELO sprinkler models. Selecteddata from each of these three tests, which wereconducted with six different ELO sprinkler mod-els, from five different manufacturers, are listedin Table 4.~13 The table provides the limits foracceptable performance followed by results fromthe submitted models for each of three majortest evaluation criteria*: (1) number of sprinkleroperations; (2) maximum ceiling level gas tem-peratures ; and (3) extent of damage, representedby amount of fuel consumption. These goodresults contributed data essential for FM-

Approval of additional ELO sprinkler models.

CONCLUSIONS

Findings from the research programs evaluatingELO sprinklers include:

1. Full-scale fire testing provided a performance-based evaluation of the ELO sprinkler. A cred-ible procedure was assured by using baselinedata from tests with standard, 1/2 in.(12.7 mm) and 17/32 in. (13.5 mm), sprinklersfor comparison of results.

2. Results of tests with the first ELO sprinklerprovided data required to develop a new FM-Approval Standard (evaluation criteria forsubsequent models) and new InstallationGuidelines and Protection Guidelines.

*Additional criteria are found in the FM-Approval Standard.3

39-

3. Compared to standard sprinklers, the ELOmodels demonstrated:

Equivalent or better fire test resultsLower discharge pressure requirementsReduced demand area requirements

4. Installation of the ELO could provide the fol-lowing protection benefits:

Improved protection with the ability to ret-rofit to upgrade existing densities.

Cost reductions with the possible elimina-tion of in-rack sprinklers, a pump, and/or on-site water storage.

REFERENCES

1. Troup, J.M.A. and Chicarello, P.J., "Large-Scale Fire Tests of Stored Commodities Pro-tected by Central D.64 Sprinklers", FactoryMutual Research Corporation TechnicalReport FMRC J.I. 0W0R4.RR, Prepared forCentral Sprinkler Company, Lansdale, PA19446, September 1992.

2. Troup, J.M.A., "Large-Scale Fire Tests ofRack Storage of Plastics Protected by CentralModel ELO-231 Sprinklers", Factory MutualResearch Corporation Technical ReportFMRC J.I. 0X0R4.RR, Prepared for CentralSprinkler Company, Lansdale, PA 19446,June 1993.

3. Factory Mutual Research Corporation,Approval Standard, Class Number 2009,"Extra Large Orifice (ELO) Sprinklers", 1994(Proposed), Factory Mutual Research Corpo-ration, Norwood, MA 02062.

4. Factory Mutual Engineering Corp., Loss Pre-vention Data Sheets, D.S. 2-8N, "Installationof Sprinkler Systems", 1989 and D.S. 8-9,"Storage of Class 1, 2, 3, 4 and Plastic Com-modities", 1995, Factory Mutual ResearchCorporation, Norwood, MA 02062.

5. National Fire Protection Association,National Fire Codes, NFPA 231-1995 "Stan-dard for General Storage" and NFPA 231C-1995 "Standard for Rack Storage of Materi-als", including Tentative Interim Amend-ments, National Fire Protection Association,Quincy, MA 02269.

6. Chicarello, P.J., Troup, J.M.A. and Dean,R.K., "Large-Scale Fire Test Evaluation ofEarly Suppression Fast Response AutomaticSprinklers", Factory Mutual Research Cor-poration Technical Report FMRC J.I.OM2R5.RR/OMOJ7.RR, prepared forNational Fire Protection Research Founda-

tion, Quincy, MA 02269 and Factory MutualResearch Corporation, Norwood MA 02062,May 1986.

7. Kung, H-C, Yu, H-Z, Brown, W.R. and Vin-cent, B.G., "Four-Tier Array Rack StorageFire Tests with Fast Response PrototypeSprinklers", The Proceedings of the SecondInternational Symposium of Fire Safety Sci-ence, 1988.

8. Factory Mutual Research Corporation,Approval Report Model ELO-231 UprightSprinkler, FMRC J.I. 0X1A7.AH, Preparedfor Central Sprinkler Company, Lansdale,PA 19446, April 1993.

9. Factory Mutual Research Corporation,Approval Report Model ELO-231 PendentSprinkler, FMRC J.I. 1X9A1.AH, Preparedfor Central Sprinkler Company, Lansdale,PA 19446, May 1994.

10. Factory Mutual Research Corporation,Approval Report Model G-XLO UprightSprinkler, FMRC J.I. 0X7A1.AH, Preparedfor Reliable Automatic Sprinkler Company,Mount Vernon, NY 10552, April 1994.

11. Factory Mutual Research Corporation,Approval Report Model F892 Upright Sprin-kler, FMRC J.I. 0X4A5.AH, Prepared forGrinnell Corporation, Cranston, RI 02910,September 1994.

12. Factory Mutual Research Corporation,Approval Report Model JN Upright Sprin-kler, FMRC J.I. 1Y9A5.AH, Prepared forGlobe Fire Sprinkler Corporation, Standish,MI 48658, January 1997.

13. Factory Mutual Research Corporation,Approval Report Model M Upright Sprin-kler, FMRC J.I. 2X0A9.AH, Prepared for TheViking Corporation, Hastings, MI 49058,January 1997.