United States Coast GuardOff ice of Research and DevelopmentWashington, D.C.

REPORT NUI1BER 519

tr~e PROJECT 798401/221 ID PD*.FLASHTUBE WATERLIGHT PHOT0.11ETRIC TESTS riv

9 OCTOBER 1970

AE FIELD TESTING AND DEVELOPMENT CENTER

NATIONAL TECHNICALINFORMATION SERVICE

UNITED STATES COAST GUAt,

FIELD TESTING AND DEVELOPMENT CENTER

REPORT NUMBER 519

PROJECT 798401~/221

FLASHTUBE WATERLIGHT PHOTOMETRIC TESTS

By

LCDR L. R. LOMERProject Officer

Field Testing anid Development CenterBaltimore, Maryland 21226

Date: _,-9 OCTOBER 1970

Submitted:

Commanding OfficerField Testing and Development Centerfaltimore, Maryl~and 21226

*Late: _____OEW1

Approved: _______________

Cief, Applied Technology DivisionOffice of Research and DevelopmentU. S. Coast Guard HeadquartersWashington, D. C. 20591

Authority: Comdt (DAT) ltr 798401/221, Serial 61.94 of9 January 1970

Neith ~ r port nor any-,exc erpts therefroM ~l&1e used f oraver glo~sal.e " oMet'n~ ~ ihu ~

permi e~ le. e of e~reanih akd Dexlpif U. CaGuard Headquar I s, "Ka~ngotj 40. !059f

ABSTRACT

'Photometric meaourements are reported for a prototypemodel of a "COSLITE Automatic Waterlight." Measurementson the flashing incandescent float light include integratedintensity and effective intensity at 85 different directions,intensity as a function of time over the fiash duration andflash rate, All measurements were repeated after the first15 hours of continuous operation.

ii

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TABLE OF CONTENTS

Title Page:- ---------------------------------------

Abstract:------------------------------------------ii

Tabla of Contents:----------------------------------iiFList of-Figures:-------------------------------------ivList of Tables:------------------------------------v

Introduction:----------------------------------------1

Materials Evaluated:------------------------------ 11 Tests Conducted:-------------------------------------1

Test Results:----------------------------------------5

Calculations:--------------------------------------9

Discussion:----------------------------------------12

Conclusion: --------------------- 12

LIST OF FIGURES

1. COSLITE Automatic Elec-tric Waterlaight: 2

2. Mounting Details of the GE 427 IncandescentLamp:------------------------------------------3

3. Details of the Plastic Lens of the COSLITE: -4

4. Intensity Vs. Time - Fresh Battery and Lamp: 7

5. Intensity Vs. Time - After 15 Hours of

Continuous Operation:--------------------------8

iv

LIST OF TABLES

1. Integrated Intensity in Upper HemisphereCandela - Seconds:-----------------------------6

2. Effective Intensity in Upper Hemisphere ofCOSLITE Automatic Electric Waterlight atStart of Test Program:-------------------------10

3. Effective Intensity in Upper Hemisphere ofCOSI.ITE Automatic Ele -tric Waterlight After15 Hours if Operation: ------------ 1

Fv

INTRODUCTION:

The COSLITE Automatic Electric Waterlight tested hereinis one of a continuing series of waverlights tested forconformity to U. S. Coast Guard Specifications for FloatingElectric Water Lights for Merchant Vessels, 46 (CFR) 161,010of 29 October 1969. The light evaluated in this report isa prototype which was submitted for preliminary inte nsitytests only.

MATERIALS EVALUATED:

Figure 1 shows an overall view of the COSLITE AutomaticElectric Waterlight. The waterlight is powered by anEveready No. 2746N, 6 volt battery which is used to flash aGE 427 lamp at a nominal rate of 50-70 flashes per minute.Figure 2 shows details of the mounting bracket and socketfor the lamp. A plastic lens which also acts as a sealedcover is shown in Figure 3.

TESTS CONDUCTED:

The COSLITE waterlight was tested for flashrate at thebeginning and end of a 15 hour test period. The integratedintensity was measured at 85 selected positions which inclu-ded the total upper hemisphere and the area included within1S degrees below the hozizon. Integated intensity wasmeasured at a distance of 150 feet with an EGG 585-66 photo-meter. Integrated intensity was averaged over 10 flashesat each location. Measurements were taken every 300 inazimuth at elevations of-150 , 00, 150, 3009 450, 600, and750. One measurement was taken at 900 elevation (lookingstraight down at the light as it would float in the t#ater).The photometer was calibrated by use of secondary standardstraceable to the NBS.

Inteni.ity as a function of time during the flash wasmeasured at the beginning and end of a 15 hour test period.The output of the S-10 photomultiplier of the EGG 585-66photometer was displayed on an oscilloscope and photographed.The integrated intensity was also sampled at the end of 15hours of operation.

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FIGURE 2

C Mounting Details of the GE-4117 Incandescent Lamp

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FIG-URE 3

Details of the Plastic Lens of the Coslite

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TEST RESULTS:

Table I lists the values of integrated energy for thecoordinates listed. After operating for a period of 15hours the mean incegrated intensity was reduced by 72% fromthe values measured at the start of the test program.

Figure 4 illustrates the intensity profile over theflash duration of the waterlight with a fresh battery andlamp. Figure 5 is the intensity profile after 15 hoursuf continuous operation.

At the start of the test program the light flashed at76 flashes per minute. After 15 hours the flash rate was741.

- 5

<,

AZIMUTH ELtVATION

900 750 600 450 0 150 00 -150

0000 0.88 .467 .34 .56 .15 .18 '1.1 .090300 - 1.45 .47 .52 .17 .1.6 .94 .10

0600 - .767 .61 $fi9 .19 .22 .67 .090900 - .59, ;67 .70 ..L9 .22 .26 .131200 - .69 .51l .54 .17 .30 .17 .13.1500 - .8 .52 .65 .14 .29 .113 .12.1800 - .90 .45 .49 .10 .16 .54 .14

F2100 -1.10 .52 .45 .15 .24 .67 .09

2400 - 1.10 .57 .49 .16 .24 .94 .10

:2700 - 1.10 .54 .50 .16 .42 -90 .133000 - 1.20 .52 .56 .19 .24 .1.40 .06

3300 - 1.60 .64 .32 .118 .20 .80 .07

Integrated In tenE, 1y in Upper Hemisphere- Candela - 'Sedonds

TABLE 1

6

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- - - -- -- - - - - - - - - - -

- - - - -- - - -

IL - N

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- COSLfl'E AU~tCATIC "'CLCaRIC 'qATFRLITE

ft CONTINUOUS

10

0 + AFTER 105 OUR OF ~ 3 04 0 56

1C 2NTINUOUS

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CALCULATIONS:

The measurements ot integrated intensity, and theintensity vs. time curves were used to compute the effec-tive intensity of the waterlight. The effective intensity

2 Idt , -where i

0.2 + (t- t1

is the instantaneous intensity of the flash between thetime limits tI and t2 '

There- is a unique solution to the equation for Ieonly when the limits of integration t1 and t2 are chosenso that they coincide -with that value of the instantaneousintensity which equals the effective intensity, Theequation was solvedfby an iteration, technique for bothintensity profiles listed' in Figures 4 and 5. The solutionfor Figure 4 resulted in an effective flash length of 0.236seconds and a multiplying factor of 2.15 for the values oftotal integrated intensity as listed in Table 1. Table 2incorporates this factor and lists the effective candeiaat all measured coordinate's for the case where the batterywas fresh.

Similar calculations resulted in an effective flashlength of 0.185 seconds and a multiplying factor of 2.31for the values of total integrated intensity -after 15 hoursof continuous operation. Table 3 lists the effectivecandelas of the COSLITE after 15 hours of operation.

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-

, , , , , , , , , , , , , , -- - - - - - - - - -

AZIMUTH ELEVATION

900 750 60P 450 300 150 00 -150

0000 1.89 .981 .731 1.20 .322 .387 2.36 .193,

0300 - 3.12 1.01 1.12 .366 .344 2.02 .215

0600 - 1.65 1.3,1 1.05 .,4t08 ,.-472 1.44 .193

0900 - 1.27T 1. 44 1.51 .408 .472 .559, .279

1200 - 1.48 1.10 1.16 .368 .645 ,36'6 .279

1500 - 1.89 1.12 l.-40 .301 .623 .280 .236

1800 - 1.i33 .968 1.-05 .215 .344 1.16 .301

2100 - 2.36 1.12 .967 .322 .515 1.44 .193

2400 - 2.36 1.22 1.05 .344 .515 2.02 .215

2700 - 2.36 1.16 1.07 .344 .903 1-93 .279

3006 - 2.58 1.12 1.20 .408 .515 3.01 .129

3300 - 3.44 1.37 .678 .387 .430 1.72 .151

Effective IL, - ty in Upper Hemisphere ofCOSLITE Automatic Electric Waterlight at

Start of Test Program

TABLE 2

10

AZIMUTH ELEVATION

90o 750 600 450 300 150 00 -150

0000 .575 .306 .222 .366 .0980 .118 .720 .0588

0300 - .949 .307, .340 .ll, .105 .615 .0654

6600 - .502 .399 .32C' .124 .144 .438 .0588

0900 - .386 .437 .457 .124 .144 .170 .085

1200 - .451 .333 .353 .111 .196 .111 .085

1500 - .575 .340 .425 .0915 .190 .085 .072

1800 - .588 .294 .32"0 .0,654 .105 .353 .0 15

2100 - .720 .340 .294 .0980 .157 .438 .0588

2400 - .720 .372 .320 .105 .157 .615. .0654

2700 - .720 .353 .327 .105 .274 .588 .085

3000 - .785 .340 .366 .124 .157 .915 .03983300 - 1.,05 .418 .209 .118 .131 .522 .0457

Effective L.. ... 1y in Upper Hemisphere of"COSLITE" Automatic Electric Waterlight after

15 Hours of Operation

TABLE 3

II

DISCUSSION:

The design of the lens/cover of the COSLITE is incon-sistent with the specification requiring minimum integratedintensity in all directions of the upper hemisphere. Thislens is designed to alter the luminous output distributionof the light source used by collecting light at all azimuthsfrom -300 to +300 in elevation and forming this into anarrow fairly intense horizontal omnidirectional beam.Table 1 shows the effects of this lens by reduced integratedintensity readings at 300 elevation. The measurementslisted in the 00 elevation column show the effects of thenarrow horizontal beam produced. This beam was very narrowwhich caused the photometer to szan through the beam asthe light was rotated in azimuth. The beam was not per-fectly horizontal due primarily to the lamp being misfocusedand misalignment of the waterlight on the goniometer table.No attempt was made to carefully realign the system becausethe results would be inconsequential in assessing whether ornot the specifications were satisfied.

CONCLUSION:

The COSLITE Automatic Electric Waterlight does not meetthe intensity and flash rate specifications required by U. S.C. G. Specifications for Floating Electric Waterlights forMerchant Vessels, 46 (CFR) 161.010.

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00"UMiIT C(M'I VOL t)AI A - 11Z'

V.3.Caa ur Fie'ljd Te- iY1J ieveloprnent Ceniter UniclassfiedC. tC

CIO Cczmt Guard ri.iBaltimorte,'Maryland; 21.26

FlAshtube Waterlight. Photi-ttc Te~ts

L1D Lloyd R. i.o'er

9 October 1970 .12_T 0--. kTNACV OT &n AN~ It04. R*, OII@*N ATmiiS ttP04

79840O/221,. &. bm o~&CS4ttNM(n hribesta " m aosp

Unlimia F~ted. IT~.M

v IV.-S. Coast Gar He4 qatr

cwtrsi mmsurwmentr are reportedi for a protqtype rodel of a "COSL~ , Autpwnatice~'ig.4., 4easurp-ment; n. the flashing incand~qee', float I ivpt inalud'e,~nortptl5tZ? and of fectiva 1;aii~ at P5 different dix :'!tcnsp t~oity as a ..- ndt ioli

t-ii~ over the flash dojraton and flash ratei All rnv@uro'fiin were repeited aher Afirst :LS hours of con L msou operation,,

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