Bsi bs en 02155 8 1989 (1999)

BRITISH STANDARD AEROSPACE SERIES BS EN 2155 8 1989 Test methods for transparent materials for aircraft glazing — Part 8 Determination of optical distortion This European Standard EN 2155 8 has the st[.]

Test m ethods for

This European Stand rd EN 2 5 -8 has the status of a

British Stand rd

U C 6 9.7 0 3.2 :6 0.1:5 5.5

This British Stan ard,ha ing

b en pre ared u der the

directionof the Aerosp ce

Stan ards Polcy Commite ,

waspublshed u der the

authority f the Bo rd of BSI on

3 No emb r 1 8

© BSI 1 -1 9

The folowing BSI references

relate to the work on this

stan ard:

Commite reference ACE/62

Draft for comment 8 /70 0 DC

ISBN 0 5 0 1 9 1 1

The European Commit e for Stand rdization, u der whose superv ision this

European Stand rd was prep red, comprises the national stand rds

org anizations of the fol owing W estern European cou tries

Austria Oester eichis hes Normung sinstitut

Belg ium Institut belg e de normalsation

Finland S omen Stand rdisoimisl to, r.y

France Association f ançaise de normalsation

Germany Deuts hes Institut für Normu g e.V

Gre ce Helenic Org anization for Stand rdization

I eland I elandic Cou ci for Stand rdization

I eland National Stand rds Authority of I eland

Italy Ente Nazionale Italano di Unificazione

Luxemburg Inspection des tra ais et des mines

Netherlands Nederlands Normal satie- nstitu t

Portug al Instituto Portug uês d Qual d de

Sp in Instituto Esp ñol de Normalzación

Sweden Stand rdisering skommis ionen i Sv erig e

Switz rland Association suis e de normalsation

United King dom British Stand rds Institution

Am endm ents is ued sinc publ cation

Amd No Date of is ue Comments

Pag e

National foreword

This British Stand rd has be n prep red u der the direction of the Aerosp ce

Stand rds Polcy Commit e and is the Eng lish lang uag e v er ion of EN2 5

“ A er ospa ce s r ie Te t method s f r tr a nspa r ent ma ter ia ls fr a ir cr a ft gla zing”

Part 8 “D eter mina tion o opt ca l d istor tion” publ shed b the European

Commit e for Stand rdization ( CEN) EN 2 5 -8 was produced as a result of

international dis us ion in which the UK to k an activ e p rt

A British Stand rd do s not purport to include al the neces ary prov isions of a

contract User of British Stand rds are responsible for their cor ect a pl cation

Com pl anc with a British Standard do s not of itselfc nfer im munity

f om leg al obl g ations

Summ ary of pag es

This document comprises a font cov er, an inside f ont cov er, p g es i andi,

theENtitle p g e, p g es2 to4, an inside b ck cov er and a b ck cov er

This stand rd has be n up ated ( se cop rig ht d te) and ma hav e ha

amendments incorporated.This wi be indicated in the amendment ta le on the

inside f ont cov er

NORME EUROPÉENNE

Mar h1 89

UDC6 9.7 0 3.2 :6 0.1:5 5.5

Ke words:Air raft in ustry,g lazing , transp rent plastic , g las ,tests,o tical pro erties, distortion

Eng lish ver ion

for aircraft g lazing

Série aérosp tiale

Méthodes d’es ais pour matériaux

transp rents pour vitrag es aéronautiques

Partie 8: Détermination

de la distor ion optique

Luft- und Raumfahrt

Prüfver ahren für transparente W erkstofe

zur Verg lasung von Luftfahr eug en

Tei 8: Bestimmung

der optis hen Ver er ung

This European Stand rd was ac epted b CEN on 19 8-0 -17 CEN member

are bou d to comply with the requirements of CEN Internal Reg ulations which

stipulate the conditions for g iv ing this European Stand rd the status of a

national stand rd without any alteration

Up-to-d te lsts and bibl og ra hical references concerning such national

stand rds ma be obtained on a pl cation to the CEN Central Sec etariat or to

any CEN member

This European Stand rd exists in thre oficial v er ions ( Eng lish, French,

German) A v er ion in any other lang uag e ma e b translation u der the

responsibi ity of a CEN member into its own lang uag e and notified to CEN

Central Sec etariat has the same status as the oficial v er ions

CEN member are the national stand rds org anizations of Austria, Belg ium,

Denmark, Finland, France, Germany , Gre ce, I eland, I eland, Italy ,

Luxemburg , Netherlands, Norway , Portug al, Sp in, Sweden, Switz rland and

UnitedKing dom

European Commit e for Stand rdization

Comité Europé n de Normalsation

Europ is hes Komite für Normu g

Central Se retariat: rue de Stas art 3 , B- 10 0 Brus els

© CEN 19 9 Copy rig ht reserv ed to al CEN member

Ref No EN 2 5 -8:19 9 E

This European Stand rd has be n prep red b the

European Association of Aerosp ce Man facturer

( AECMA)

After enquiries and v otes car ied out in ac ord nce

with the rules of this Association, this Stand rd has

suc es iv ely receiv ed the a prov al of the National

Associations and the Oficial Serv ices of the member

cou tries of AECMA, prior to its presentation to

CEN

According to the Common CEN/ CENELEC Rules,

fol owing cou tries are bou d to implement this

European Stand rd: Austria, Belg ium, Denmark,

Finland, France, Germany , Gre ce, I eland,

I eland, Italy , Luxemburg , Netherlands, Norway ,

Portug al, Sp in, Sweden, Switz rland and the

UnitedKing dom

Contents

Pag e

1 Scope and field of a plcation 3

1 Scope and field ofappl cation

This stand rd specifies the method of measurement

of optical distortion of she ts in transp rent

materials, which consists of determining the chang e

of dev iation ov er the entire area of the she t

The method alows she ts to be v iewed at difering

ang les which are specified ac ording to the qual ty

of the she t u der test

2 Ref rences

EN 2 5 -6, A er ospa ce s r ie — Te t method s fr

tr a nspa r ent ma ter ia ls fr a ir cr a ft gl a zing —

Pa r t 6: Deter mina tion o optca l d efe ts

3 Definitions

Optical distortion is defined as local v ariation of

optical dev iation which results in distortion of the

imag e per eiv ed on v iewing throug h the p nel.Th s

k own straig ht lnes become c o ked or curv ed

A g rid board hav ing lne sp cing of 25mm is

mou ted vertical y A g raticule hav ing a sy stem of

equaly sp ced l nes in two directions at9 ° to each

other is desig ned to be used with a suita le lantern

projector so that at a distance of4,5m the projected

imag e can be ma e coincident with the g rid board

To av oid distortion of the imag e, measurement shal

be restricted to a square a out 1m × 1m at the g rid

board An iris dia hrag m ma be useful to reduce

the a erture of the lens The specimen shal be

mou ted so that the area being ex mined is1,2m

f om the g rid board The mou ting ar ang ement

shal alow the specimen to be placed at v ary ing

inclnation to the horiz ntal plane

5 Specim ens

For the purpose of this stand rd, the specimens are

entire she ts The entire surace of each specimen

shal be carefuly cleaned av oiding s ratching or

c azing

6 Procedure

6.1 Ma im um g ra ient

W ith the specimen mou ted at the specified v iewing

ang le, the ma imum g ra ient of the projected imag e

with respect to the g rid board lnes in both

directions shal be as es ed

The specimen shal be rotated 9 ° in its own plane

and the same as es ment repeated In cases of

doubt the imag e of the defect shal be broug ht to the

optical a is of the a p ratus and projector

a justments ma e to ov er ome lne shift due to

displacement

6.2 Sharp disc ntinuities

S arp dis ontin ities “ d” in the projected imag e

shal be measured as indicated inFig ure 1

N T The e amination for sharp dis ontin ities, ty icaly

shown inFig ure 1 is neces ary in ad ition to the e amination for

major an minor defects in EN2 5 -6 since in omo enities

resulting in chang of refactiv in e ma not show up in

EN2 5 -6

7 Expr s ion ofr sults

The g ra ient in each area of distortion shal be

ex res ed as a slope e.g 1 in 17; sharp

dis ontin ities shal be ex res ed as measured as

displacement in mm

8 Test report

At each of the specified v iewing ang les as specified

in the material stand rd, the number of oc asions

when the g ra ient is ste per than the ag re d lmits

shal be reported; lkewise the n mber of oc asions

when the dis ontin ity “ d” exce ds the specified

lmit shal be reported

Fig ure 1

National appendix A

The United King dom p rticip tion in the prep ration of this European Stand rd was entrusted b the

Aerosp ce Stand rds Polcy Commit e ( ACE/-) to Tech ical Commit e ACE/62 upon which the fol owing

bodies were represented:

British Plastic Federation

Ministry of Defence

Society of British Aerosp ce Comp nies Limited

National appendix B

The British Stand rd cor esponding to the European Stand rd refer ed to in the text is identical in n mber

and title with that g iv en in clause2

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