IS 12866 : 1989
(Reaffirmed 2003)

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Indian Standard

PLASTIC TRANSLUCENT SHEETS MADE FROM THERMO-SETTING POLYESTER RESIN ( GLASSFIBRE REINFORCED) SPECIFICATION
Second Repnnt OCTOBER 2007
( lncludmg Amendment No I I

UDC 678 674 067 5-41

© BIS 1990

BUREAU

OF

INDIAN

STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002
June 1990

Price Group S

AMENDMENT NO. 1 APRIL 1999 TO IS 12866: 1989 PLASTIC TRANSLUCENT SHEETS MADE FROM THERMO-SETTING POLYESTER RESIN (GLASSFIBRE REINFORCED) - SPECIFICATION
[Page 1, clause 1.1 ) -c--Subvtrtutc the following for the existing clause:
"1.1 TIll'> standard SIJCl.:lfll'::i dIIllCnSIOIl..'i.

tolerances. strength and

light

transuussron of glass fibre reinforced translucent plasucs sheering of the profiles specrfrcd m IS 277 : 1992 'Specsfrcanon for gulvaruzed steel sheet (ptaru and corrugated) (fifth rCI'{SlOn)', IS 459 1992 'Spccrfrcauon for unrcruforccd corrugated lind semi-corrugated asbestos cement sheets ( tlurd revision )', and IS 1254 IWI 'Specitrcanon for corrugated ajunnruum sheer ( ttnrd re~'/SlOn)' for use ,11 roofs ,.

c Page 1, ctanse 2.1) -

Subsuturc tbe following for tbe exrsrmg clause

'2.1 The foflcwmg ludran Standards arc necessary adjuncts to the standard.
IS No.
'277
199~

rotGalv;l1l17e'-.! vtccl "heels {plam and corrugated) (fifth Uurcmforccd corrugated and scull-corrugated sheets (llllrd rrwsion) Corrugated alunumum sheer i tlurd retlHfJn)
rell~JO")

459: 1992 1254. ]991

asbestos cement

67..tfl 11551

1994 Un...arurarcd polyester rcsm systems ([tnt revrston
19~6Glo1""j.,

s

ubrc chopped strand mal for the rcuiforccmeut of polyester rC'."1Il ~Y"(CIl1" '
Subsututc 'IS 117..f6 : 1'N4' for 'IS 1)7"'6:

(Page 1, dIl/LH:! 3.3, llfth line) 1971'

( CElJ 5 )

Flooring and Plasterin, Sectional Committee, DOC S

FOREWOR.D This Indiaa Standard was adopted by tbe Bureau or Indian Standards on 25 January 1989··ncr the draft finalized by the Water Supply and Saoitation Sectional Committee had been approved by the Civil Engineering Division Council. This standard deals with the quality, performance and overall dimensioDs of glassfibre reinforced corrugated translucent sheeting for buildm8 purposes, It includes sheeting of all profilca given in IS 277 : 1985 'Specification for galvanezed steer sheets (plain and corrugated) (fourth rmsion ,'. IS 459 : 1970 'Specification for unreinforced corrugated and semi corrugated asbestos cement sbeets ( second revision )', and IS 1254: 1975 'Specification for corrugated aluminium sheet (suond relliston I", For the preparation of this standard, considerable assistance bas been derived from BS 4154 ( Part I ): 1985 'Specification for corrugated plastic translucent sheets made froID. thermosetting polyester resin ( glasefibre reinforced Y. issued by the British Standards Institution. U.K. For the purpose of deciding whether a particular requirement of Ihis standard is complied with, the final value. observed or calculated. expressins the result of a test or .oalysis. sball be rounded off In accordance with IS 2 : 1960 "Rules for rounding off numerical values l nV;.Jed y. The number of significant places retained in the rounded off value should be the lame as that of tbe Specified value in this standard.

IS

I~:

198t

Indian Standard

PLASTIC TRANSLUCENT SHEETS MADE FROM THERMO-SETTING POLYESTER RESIN ( GLASSFIBRE REINFORCED) SPECIFICATION
1 SCOPE

1.1 This standard specifies dimensions. tolerances, strength and light transmission of glassfibre reinforced translucent plastics sheeting of the profiles specified in IS 277 : 1985 'Specification for galvanized steel sheet ( plain and corrugated) <fourth revts Ion ). IS 459 : 1970 'Specification for unrcioforced corrugated and semi corrugated asbestos cement sheets (second rell/ston)' and IS 1254: 1975 'Specification for corrugated aluminium sheet ( second rnu;on )' for use in roofs.

3.2 The glassfibre used as remforcement s1:lal1 be In the form of chopped strand mat having a tughly soluble tnodrfied polyester binder in accordance with IS 11551 : 1986 having B density of 450 81m' and minimum width of 500 mm. 3.3 Special grade of unsaturated polyester resin having a refractive index matching that of the glassfibre ( that IS 1-53) and conformmg to the broad specificanons gi ven below shall be used. The methods of testing the resin properties shall be in accordance with IS 6746 : 1972 (Physical data in liquid state);
a) Viscosity at 25 cC, in cps ( Brooke-field LVF spindle 2/12 rev per min)
b) Specific gravity at 20
G

1.1 The recommended temperature range over
which the sheets can be used as roof lights or for glazing should be from - 20 to + {j()°C. 1 REFERENCES

: 400 to 500

2.1 The following Indian Standards are necessary adjunctl to this standard:

e

: 1 11
: 2S to 30

c) ACid number, in mg KOH/g

IS No.
277 : 1965

rut«
Galvanized steel sheets {plam and corrugated ) (fourth revision)

d) Solids.

10

percent

: 65

4 PROFILES, DIMENSIONS AND TOLERANCES

459 : 1970

Unreinforced corrugated and semi corrugated asbestos cement sheets

4.1 ProW.. The profile of the sheet shall match the profiles specified in the approprrate Indian Standard for the particular material as given m Table 1 which will surround the translucent sheets. 4.1 The dimensions of the sheets are Biven m Table I. 4.3 Sheets With higher thickness than that specified in Table I may be made as agreed between the purchaser and manufacturer.
4.4 For the purpose of measuring thickness. a thickness gauge shal! be wed and it sball be measured at least at 10 random points on all the four Sides and the average value shall be taken.

( second revision)
1254: 1975

( second revision)

Corrugated

aluminium

sheet

6746 : 1972

Unsaturated polyester resin systems for low pressure fibre reinforced plastics G1a.. fibre chopped strand mat for tho reinforcement of polyester resin system

11551: 1986

3 MATERIAL
3.1 The material shall be composed of a thermoletting styranated or acrylated polyester resin system remforeed with glasafibre, This system may include curing agents, catalysts and light stabrHzen. Fire retardant grade of resin and colouring matter may be used only in special cases as agreed to between the purchaser and the manufacturer.

4.5 The depth of each of the corrugations shall be measured on the smcoth stde and the maximum deviation 10 any of the cases measured. shaU Dot exceed the limits specified 10 Table I.

IS 1Z86li :

1m
6 PERFORMANCE REQUIIlEMENI'S
6.1 Dea"lJ The Dominal weigbt of ]·10+0·15 mmlbick plaiD sbeet shall be I'S5 kll sq m.

4.6 For the determining the pitch of the corrugation. total1cogth over 6 pitches shall be measured and tbe length measured over these 6 pi tcbes shall Dol vaT)' from 6 lime tbe .peo,fied pitcb by lb. tolerance. aiven ia Table 1.

5 WOIlKMANSHlP AND PlNISH
S.t The sheets sball have a smooth surface finish on both sides. A resin rich surface oa the exposed part of the sheet IS necessary to ensure that the .heer has good weathering pFopertiei. 5.% The moulded sheets shall be reasonably free from visible defects, such as. fibre pattern, foreign inclusions. cracks, crazing, die-lines, pin holes. striations, and bubbles Over 1"3 mm in diameter.

6.1 GlusC_

The glass content in the laminate shall not be less than 30 percent when tested in accordance willi Annex A. 6.3 Water AbsorptioD The sheets shall not absorb water in excess of 0'3 percent when tested in accordance wjtb Annex B. 6.4 Hordo... ( Ba.....1 ) When the sheets are tested with the method given In Annex C. the Barcol hardness shall not increase by more than 30 percent or its initial value.
6.S Bolt Sbear Tell When tested in accordance with Annex D, the arithmetic mean of the loads at which the first tear appears, shall be not Jess than 375 N. The load at which the first tear appears while testing any one of the specimens, shall be not less than 2;0 N.

5.3 Special Floi.....

A clear tissue of fibregfass surface mat or polyester mat may be applied to the sheet surface (on the side exposed to weathering) during manufacture
Alrernelively, PVF and polyester eladdmg films can be to improve resistance to weathering

bonded to the sheet surface ( on the SIde exposed to weathering) during manufacture to provide excellent weathering and chemical resistance and longer life

Tabl. 1 DimensloD ADd Tolerances of Glass6bre Reinforced Corrugated TI'aDS'aceot Rootlight Sileets (C/au"s 4.1,4.2,4.5 and 4.6 )
All dtmensrons
IQ

munmetres.
O'erall Wldtb
R
(8)

No.

sr

T)"Je of Sbee'

Profile No.

Depth of COrrtlRatla.
D

Pilch of CorruKatlqa
.~----.

Eft'ectlu Minim. . Thll"koe.. Width

Tole. ranee
(') +3 +3

P

Toleranee

Tole:: Tole. ranee ranee:
(9) +10

,

T
(II) ('1

Tole--

.

Length of
Shret

,
(13)

ranee
(12)

(I)

(2)

(3)

(4)

(6) 146 338

(7)
+6
~9

(10)

"

Tolerance
(14)

.

i) COrfUl8ted al5besto!l cement

I

48

profile in

2

acccrdeece with IS 459: 1910
ii) Corruia tcC:

4'
I7'S 12'5

-,

10S0

-3 73

+6

-2

I tOO

-,

+lO
+10
-j

+lO

-,

-,

+O"U

1 7'" 0-5 percent 2000 of lCDltb 2300 3000
1800 0·5 percent 2200 of lCDltb 2300 2800 3000 1800 2 _ 0'5 percent of lenltb 3000 3600

3
4

atee l

protilc in
accordance with IS 277 : 1985

±2'S ±2'S

+'

660 81O
910

+0'15

68O
.30
19

±23
'0 23

iii) Corrugated S aluminium .heels
profile ID accordance with 6 IS 1254: 1975 7

73

+'

6,0 '00

±23

t't

+0 IS

3. 38

190

12'

±, ±3
2

7'" 830

±2' ±23

IS IZlI66 : 1.,
6.6 Load Deflection Test This test is applicable only to corrugated sheets and flats of curved sheets. When three sheets of 1-10+015 mm thickness are tested in the manner described in Annex E. none of the sheets shall rupture although minor cracking around the areas of support or loading shall be permitted. The total load as shown in Table 2 shall produce a deflection of not more than 15 mm (that IS. spanl70) on any of the sheets. Table 2 DcOection U..., Test Load ( Clauses 6 6 and E-I.3 )
Profile No. ju Accordance With Table
(J)
)

The' light transmission propertses of sheets containing tmred material are dependent upon the degree of colouring required and the minimum total transmission tor coloured sheets shaJl be subject to agreement between the purchaser and the manufacturer, 7 SAMPLING AND NUMBER OF>TES'I'S'

7.1 S<&lo of 5_,llog
7.1.1 Lot

Total Load N
(2)

In any consagnment, all the sheets. of the same type and of the same ttnckness add manufaoturcd under SImilar conditions. of prcducnon shall be grouped together to constitute a lot. 7.1.2 The confcrmrty of the lot to tbe requirements of this specaficatton shall he. ascertained on the basis of tests on the sheets. selected from it. 7.1.3 The number of sheets to be selected at random the Jot shall be In accordance with Table 5.
Table 5 Sample Size
Lot S'ze
( I)

2
3 4 5 6 7

1100 1 100
190 190 190 850

"0

6.7 Lighl DilJusioo When determmed in accordance with Annex F, the gradient constant shall lie withm the limits set our In Table 3 for the .appropnate class of sheet. Table 3 Light DitrusWn GrlHlieot CODsteot G

Sample Siu
(2)

Up tv
501
[0

500 I 000

3 5
7 10

1 001 to I 500 1 501 and above

7.2 Nombel" of T..t.
Diffusion Ciassl8eaUoo
(1)

Description
(2)

Gradient ConstlLnt G
(')

7.2.1 All the sheets selected a. in 7.1.3· shall be measured for dimensioes aed examined for T'fSUIIi defects. 7.1.2 00 <aOIO seteaed wet, tilt IcIIta shall be perforreed .. indicated 7.
8 TRANSPORT AND sroRAGIi 8.1 Sheets should be stored on 8at~ clean battena at 1 500 mm centres and should be protected against being blown away. Sheets stored in the open. should always be covered with water-proof cover. Otherwise. entrapped water causes tbe sheets to lose colour in prolonged exposure to sunlight. 9 MARKING 9.1 Each sheet .ball be Ramped or marked by any SUitable method with the following mformation. a) Indication of the source of manufacture.

I
11

111

IV

Clear Moderatc1y diffusinl Heavi Iy diffUSing Very heavily dlffurin&

Above O'SO 0"32 to 0·80 0'10 to 0 32 Belo.w 0:10

I.

6.8 Transmission When determined in accordance with Annex G. the gradient constant shall lie within the limits set out in Table 4 for the apprcprtate class of
sheet.

Table 4 Minimum Total Light Traosmissioo
Diffusioa Clasrd8eatlOD
(1)

MIIIIlIIum "l:olal Traollwlssion
(2)

I II

III

IV

80 75 70 60

aod
b) Year and dale of reenufacture,

IS 12B'6 :

J!I8~

ANNEX

A

( Clause 6.2 )
METHOD OF TEST FOR GLASS CONTENT A-I GLASS CONTENT
A-t.1 The &Iasscontent in the laminate shan be determined UiiOB the following procedure. The specimen is first weighted on analytical balance in 8 previously weighted, igolted crucible. The specimen is pieced in the furnace at a temperature Dot greater than 343 ~C. The temperature of the furnace is raised 10 565 ± 28"C, at a rate tbat wiU not cause blowing or loss of inorganic filler. The specimen aed crucible are then ignited at this m..ximum temperature to constant weight ( 2-6 hours depending on the thickness) and

allowed to cool in a desiccator. The Joss in weight
s.haH be determined by weigbing: the residue:

Glass content. weight (%)

_~"'';;-'''W''--'-' x 100
W.

where
W1
....

loss in weight. and original weight.

We

s::o:

ANNEX

B

( Clause 6.3 )
METHOD OF TEST FOR WATER ABSORPTION
11-1 WATER ABSORPTION

then weighed again immediately. The absorption ccefflcrent shall be determined from the following:

8-1.1 Test pieces shall be cut to size 50 x 50 rom area or of diameter 30 mm, the exposed edges of the test pieces shall be coated with resin to preveot inter-laminar attack. The ~tion.s of the pieces shaH be cleaned. drted for 24 b In aIr batb at 50 ± 3°C and then allowed to cool in a desiccator, Following tbis, tbe pieces shall be weighed Immediately With the help of a chemical balance. Next the test pieces shall be Immersed In distilled water for 24 h at 27 ± rc. taken out. the water WIped out with a piece or dry cloth and

W_ 2-W A= -_1 W,
where

X

100

A = absorption coefficient ( percent ).

WI = weight before immersion. and
W,- = weight after Immersion.

ANNEX

C

( Clause 6.4)
METHOD OF TEST FOR BARCOL HARDNESS C-I HARDNESS C-I.t With the indentor perpendicular to the test surface. a light hand pressure IS exerted 3gamst the instrument to drive tbe spring loaded
4

indentor into the material and the hardness dial readins is taken and recorded after a 10 second interval An average of at ICBst S testa shall be used for determining hardness.

IS 12866 : 1919

ANNEX

D

( Clause 6_5 )
METHOD OF TEST FOR BOLT SHEAR TESr D·I BOLT SHEAR TEST D-1.1 Cut the test specimens 150 x 30 mm. to be as fiat as possible depending on the configuration of the sheet. from a sheet with the long dimension of the specimen in the longitudinal direction of tho sheet. On the centre line of each specimen, drill two clean holes, the centre being 38 mm from each end of the specimen, using 0"8 mm twist drill, the specimen being fully supported on a wooden backing.

the pins loosely through the holes in the specimen. Place no restraint on tbe specimen. Apply the tension at a constant rate such that the jaws of the machine extend at 13 mm ± 5 percent per minute until the first tear in the specimen occurs. D-1.3 Report
Record the tearmg load dunng the test of each specimens, Report: a) the conditioning. if any previously given to the specimens; b) the Individual test results; and c) the arithmetic mean of the test results all six specimens.
00

D-l.1 Procedure
Carry out the test at a temperature of 27±2 c C . Place the specimen on a tensile testing mach me having pins of diameter 6 -±- 0"130 mID. Thread

ANNEX

E

( Clause 6.6 )
MEmOD OF TEST OF LOAD DEFLECnON TEST

£.1 LOAD DEFLECTION TESr £.1.1 Test Spe<lme.. There shall be three test specimens. £.1.2 A,......I.. The test rig is shown in Fi8. 1. The length of the bearers and runners is at least equal to the width of the sheet being tested and the supporting aurfaces of the bearers are 50 mm wide. level and parallel with each other. The timber blocks which ensure that initially the load is distrrbuted over the aat areas of tbe sheets and IS not concentrated on. the ridae of the corrugations. are parallel and

placed ( as shown) at one-fourth or the span from the bearers. The load spreader is Jaid symmetrically over tbe centres of the runners. The weight of all this timber shall be counted as part of lhe lOla' load.
E-1.3 Procedure

Apply the load incrementally bUI.. steadily and umformly as possible. up io the least load specified in Table 2. MalDtain the test load for at least 5 minutes and then measure the deflection of the underside of the centre of the corrugation nearest to the centre of the sheet. Record the deflection separately for each test.

5

IS 121641-: I,.,
LENGTH OF SHEET '360

100 .50 TIMBER

w

RUNNERS

I

",,"0---100.5.0 TIMEU!R BEARER

'n
t :::.
lO~O

All dimensions
FIG. I

In

rmlhmetres,

TESTING FOil LOADING AND DEFLj:OCTION TEST ON SHEETS: PROFILES 1.2.6.7 AND

8

ANNEX

F

( Clause 6.7 )
METHOD OF TEST FOR LIGHT DIFFUSION BY SLIT DIFFllsrON PHOTOMETER
Fool UaM 91RUAlC»l D:SIr. An uncorrected sKeaium rectiior~tyIJe pholOCeU (with exposed seesmve surface 60 mm in dieOlder) IS mounted at the opposae end of tbo box from the lamp house in a compartment 230 mm long, painted matt white internally. In the wall of the photocell compartment facing. the lamp IS a rectangular bole: 1"15 mm Wide and 240 mm high; CDvcnxl: WIth medium opal acryhc pilutics mattl'i.l. This·fhed aperture is screened from the illummatiGR froID slit A by a ftl0'Y8.bk: semen with a stit 2S IDIlI wide and 240 mm IoBg ( alit B ). The movable screen is arranged to slide (preferably between two preset stops ) SO that the slit can be posmoned enher just Inside Or Just cnrssce tbe shadow formed by one edge of the slit A. The interior of the box between the two slits is pam ted matt black, and gaps aTC left in the Sides and top of the box unmediately in front {that IS on the Side away from the 111.mp ) of slit A. so that a
6

F-Ll T_ r

Spodmoa.

F-I.ZA.......... The arrangement of the instrument is indicated in Fig. 2. It consists essentially of a bO'X I 350 JDIII" long. 250 mm wide and 300 rom high. At one eDlllI'I tb. lalap blDU!M:l' contlurrmg a 60 V. double cappeo tdibetar tuegseen ilv:nacnt lamp mounted vorti..Ily, lbe waU 01 tee lamp bOlKC at tbe end bClIrmd dw lamp is peirtted matt white, bat tbe reDlarDHIgiutido'surfiLees are matt black.
l

In tbe centre of tbe _ ..all of tboo llIDlp _ is a vertical slit (360 mm from the lamp ). 300 mm bigh ecd 20 rom wide (with chamfered cdSes ) which allows a narrow beam of light with sharp edges to be projected down the length of the box ( slit A ).

1S)1I6/i:

~

ALL ""'A1T WH1TE INT{RNAltr

OP4l PLASTICS SOI£ EN

ALL NATT BLACK iNfERNAllY

SAMPLE {MEASURED WITH CORRUGATIONS AT RIGH1' ANGLES

to

LENGTH OF SlJTJ

,
:8 LINE OF SHAOOW FRO,,",

~~;

lIIl~UT WHITE IND WAll. lItESJ MATT

.lACK

INTE~N"U't

ILLUMINATING SL'-'--SAMPLE

iO W fUBUlHt LAMP

76'
UNCO~fJECTEO PHOTOCelL (iQ orAMETER WORMING SUF;!f:ACE)

MOVEABLE SCREeN WlT H SUT

2'!1 WIDE ICHAt,"'F"eREO EDGES I
ALTERNATIVE POSITION SHOWN

O()llED
SEC TlONAL "lAN

ILLUMINATING SLIT lA, 10 WIDE. lOQ HI GH WITt-t CHAMFERED eo ees

SECTIONAl.- ElE.VATION

All dunensrons m mnttmetres.
FIG. 2 SLIT DIFFUSION PHUTOMETER

large sample of diffusing material to be measured can be traneversed across the silt. The Width of the gap to be left is determmed by the amphtude of the largest corrugation. on any of the matersala to be measured and In thrs way, a band JOu mm Wide around each Side of ol. large sample can be examined.

in tbe slot (with corrugations fUDOin. borizontallr ) and the movabJe screen ia set alternately
against ODe or the other of the stops limltlDg ita travel. With the sample Immediately in From of sht A, and slit B 10 the beam. move the sample past slit A. ( keeping it always entirely covered by tbe sample) and observe the variations in reading of the galvanometer. Note the maximum Uld mirnmwn readings and choose a position of the sample so that an average readmg IS obtained ( aruhmeuc mean of miJumum and maximum). Leave the sample In ttns posillon and move slit.ll to the OPPOSIte end of ItS travel. and Dote tbe galvanometer reading again. The gradient constant C IS the ratio of the readings wrtb the alit in the two position, mmus one. Thus if R b and R i are the readings with the silt B respectively lD tbe beam and In the shadow.

F-l.3 Pro"",,ur.
Before making measurements on any sample. It is to set the stops governmg the travel of slit B. so that at one end of its travel. one of lts ~dgts is c01Rcidenl witb the edge of tbe sbadow thrown tty slit...4. and at rbe shadow. The total amount of travel, allowmg sufficient margm for overlap, IS about 30 mm.
D~ssary

The ~tual measurement of dnfusrcn IS made by relating readmgs of a galvanometer connected 10 the photocell when the sample under test IS placed

1

IS U8" : 1989

G ( Clouse 6.8 )
G-I ME,,"SUREMENT OF TOTAL LIGHT TRANSMISSION BY INTEGRATING BOX PHOTOMETJi;R G-I.I TOft for Spe<lmeD G-I.:1 ""pp.......
The apparatus is constructed as shown in Fig. 3. It consists of a box havmg internal drmenstons of I 400 x 1 400)( 600 mm high whtch is pamted matt while insrde. In the centre of the top of the

ANNEX

material. Mirrors 152 mm. wide and 1370 mn: lang are fixed below Itie sky around Its pertphery between it and the mtegraticn box. with one 01

the mirrors binged to alJow samples to be inserted
and removed. In this way. the area of the opal

panel is extended to approximate an
large tkY.

infiflitel~

G·l.3 'Sky' Brightness Distrlbullon
When assembling the apparatus the 'sky' brightness distribution shall be measured using a directional photocell with a 15° field of view which is fixed at the centre of the aperture and can be rotated about an honzontal axis and set at any angle from 0° (horizontal) to 90'" in a verticaJ plane. The photocell is connected to a galvanometer and the readings noted every 10°; from 0 to 9ft, in a vertical plane pas.'Hug. through the centre of a side mirror. The readings are repeated WIth the photocell turned through 90" in a horizontal plane.
PHOTOelECTRIC CELL

box is an aperture 600 mm square, over which the samples are placed. At the centre of the aperture and level with it is suspended 25 rom diameter consine-corrected photocell facing downwards, and connected to a gal vanometer . At ISO rom above the aperture is fixed a drffusmg source to represent an 'overcast sky' which consists of eight J 220 mm 40 W, 'colour matching' fluorescent tubes above a I 370 mm square sheet of medium diffusing opal acrylic plasncs

M'RRO~-

":":'~' :. (:
- ~ ~

, - -\..

:

INTEGRATING BOX
.400 1I14QOlL600 ttlGH

ALL INTERIOR S.URFACE OF BOX PAI....tEO wHiTE
DOOR

DOOR'

All d.IDeQsioQS ip nun.metres,
FIG.3 DIAGR.&.M OF INTEO&ATlON

Box

PHOTOMETER

s

IS 11866 : 1989
G-J.4

meet et RolIo<tlaol from _

U _ Toot

D1Ie to tb· ..".11 distance betweeD the lamp" Meet and the opal panel illuminator, some light
is bound to be reflected back: from the sheet to iQlClU.Je the bri,htnesl of the 'sky'. The amount reflected will depend principally on the diffUSing power of the material, and the increase of bri.bt0 . . . will probably Dot exteed 4 percent except for the: moat hiJbly dilfurina material.

without any sample in position. then the rcadlDg ( R. ) WJtb the sample In place aDd finally tbe reading ( R.) Without any ample Blain. There should be very little difference between the first Bod the third readings, and if this is the case. their mean is used to divide into the reading with tbe sample in position. Calculate the totel light transmission of the specimen by multiply the value oftbis ratio factor (
}o=

G-J.5 I'ro<Mare To take measurements. awnch on the fluorescent lamPl in the 'sky' and allow them to stabilize for at leu. J5 minutes. DUTi~g the measurements. keep the voltage eupphed ro the lamps constant, with a conatanl voltase transformer, jf necessary.
Fint note l.be nadinB ( R1
)

'l(R,~Rs)

by the

correction

16-:5 ). where

the value of D' cor-

responding to the value of 'G' (which should be measured first as gi"en In E-J.l) ,s determined from the curve 10 Fig. 4.
G~J.6 Report the mean of the results for the four specimens.

of the galvanometer

1D

,I' i~. 'I: ",' .,
i,
,! :r.

- ,
-

. '" "
':
, ..

·

,
I

,
"

t 'I

'.

,.1

'J

J "

".-..r "

..

,.

',,"

r

"

'"

,I,
.
!

'"

,
"

" I:, , .
I

:=
OM

. .. ...
z
0.1 0-2 0·3 0' 0') 0-6

, ", ,-

,
"
I
J

1-;

I"

,

,

I!

,'I,

:'1 " " ill. II 'I!. .1 .·
'I
I.

,'I,:

:

'.

"

1 .': :,1 '.

, '_.I~.!'
"
'.
0-7 0·8 09 1.0
GR AorEN T CONST AN T - G

., f4i

"

,,'1,',1.1

I.,

I, lew.,;.
1./

p(O~ 4

RELATION BETWBEN GRA.DIENT CONSTANT AND RBPLECl'lON FROM SHEBTJ

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BIS IS a statutory msutuuon estabhshed under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the acuviues of standardazatron, marking and quahty cernficatron of goods and

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Amendments are ISSUed (0 standards as the need anses on the basis of comments Standards are also reviewed pcnodrcallv a standard along With amendments IS reaffirmed when such review Indicates that no changes are needed. If the review mdicates that changes are needed. It IS taken up for revision Users of Indian Standards should ascertain thatlhey are In possession of the latest amendments or edition by refemng to the latest Issue of '815 Catalogue' and . Standards Monthly Addrttons'

Thts Indian Standard has been developed from Doc No CED 5 (4462)
Amendments Issued Since Publication

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Date of Issue

Text Affected

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