Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 9000-4 (2008): Basic Environmental Testing Proceduresfor Electronic and Electrical Items, Part 4: Damp hear(Steady state) [LITD 1: Environmental Testing Procedure]

IS 9000 (Part 4) : 2008rsc 60068-2-78 : 2001

~~~11GT~~3lT~~ tRTe-TUT~~ 4 ;p:J \JiliJlT (~ 3rcm!n)

( rr&fT g;Rt8fUT )

Indian Standard

BASIC ENVIRONMENTAL TESTING PROCEDURESFOR ELECTRONIC AND ELECTRICAL ITEMS

PART 4 DAMP HEAT (STEADY STATE)

( First Revision)

ICS 19.040; 29.020

©SIS 2008

BUREAU OF INDIAN STANDARDSMANAK SHAVAN . 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

September 2008 Price Group 3

Environmental Testing Procedures Sectional Committee , LITO 01

NATIONAL FOREWORD

This Indian Standard (Part 4) (First Revision) which is identical with IEC 60068-2-78 : 2001'Environmental testing - Part 2-78: Tests - Test Cab: Damp heat, steady state' issued by theInternational Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards onthe recommendation of the Environmental Testing Procedures Sectional Committee and approval ofthe Electronics and Information Technology Division Council.

This standard was first published in 1979. This revision has been undertaken to align it with latestIEC publication of IEC 60068-2-78 : 2001.

The text of IEC Standard has been approved as suitable for publication as an Indian Standard withoutdeviations. Certain conventions are, however, not identical to those used in Indian Standards.Attention is particularly drawn to the following:

a) Wherever the words 'International Standard' appear referring to this standard, they should ­be read as 'Indian Standard'.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the currentpractice is to use a point (.) as the decimal marker.

In this adopted standard, reference appears to certain International Standards for which IndianStandards also exist. The corresponding Indian Standards, which are to be substituted in theirrespective places, are listed below along with their degree of equivalence for the editions indicated:

do

Degree ofEquivalence

TechnicallyEquivalent

Corresponding Indian StandardInternational Standard

IEC 60068-2-2 1974 Basicenvironmental testing proceduresPart 2: Tests - Tests B: Dry heat

IEC 60068-1 : 1982 Environmental IS 9000 (Part 1) 1988 Basictesting - Part 1: General and environmental testing procedures forguidance electronic and electrical items: Part 1

General (first revision)

IS 9000 (Part 21Sec 1 to 5) : 1977 Basicenvironmental testing procedures forelectronic and electrical items: Part 2 Dryheat test,Section 1 GeneralSection 2 Dry heat test for non-heatdissipating items with sudden change oftemperatureSection 3 Dry heat test for non-heatdissipating items with gradual change oftemperature .Section 4 Dry heat test for heat dissipatingitems with sudden change of temperatureSection 5 Dry heat test for heat dissipatingitems with gradual change of temperature

On~ the English language text of the International Standard has been retained while adopting it as anIndian Standard, and as such the page numbers given here are not the same as in the IECPublication.

~or the purpose of deciding whether a particular requirement of this standard is complied with, thehnal value, ob~erved or calculated, expressing the result of a test or analysis , shall be rounded off ina~c~~dance with IS 2 : 1960 'Rules for rounding off numerical values (revised) '. The number of~Igm.flcant places retained in the rounded off value should be the same as that of the specified valueIn this standard.

IS 9000 (Part 4) : 2008rsc 60068-2-78: 2001

Indian Standard

BASIC ENVIRONMENTAL TESTING PROCEDURESFOR ELECTRONIC AND ELECTRICAL ITEMS

1 Scope

PART 4 DAMP HEAT (STEADY STATE)

( First Revision)

This part of IEC 60068 provid es a tes t metho d for determ ining th e sui tab ility of elect rotechnicalproducts , com ponents or equ ipment fo r tra nsportation , storage and use under condit ions ofhigh hum idity The tes t is primarily intended to permi t the observat ion of the effect of highhum idity at constan t temp erature wi thout condensation on the spe cimen ove r a prescribedperiod .

This test provides a number of preferred severities of high temperature , high hum id ity and testduration . The test can be applied to both heat-diss ipating and non-heat dissipating specimens.

The test is app lic able to sma ll equipment or components as well as large equipment havingcomplex interconnections with test equipment external to the chamber, requiring a set-up timewhich prevents th e use of preheating and the maintenance of specif ied condit ions during theinstallat ion per iod

2 Normative references

The following normative documents contain prov is ions which , through reference in this text ,const itute provisions of this part of IEC 60068 . For dated references , subsequent amendmentsto, or revisions of , any of these publications do not apply However parties to agreementsbased on this part of IEC 60068 are encouraged to investigate the possibility of applying themos t recent editions of the normative documents ind icated below. For undated references , thelatest edition of the normative document referred to appl ies Members of ISO and IEC mainta inregisters of currently valid International Standards.

IEC 60068-1, Environmental testing - Part 1: General and guidance

IEC 60068-2-2, Bas ic env ironmental testing procedures - Part 2: Tests - Tests B: Dry heat

3 General description

In this test , the spec imen is introduced into the chamber, both of which are at laboratorytemperature .

The condit ions in the chamber are adjusted to the severity required according to clause 5 andmaintained for the prescribed time.

Because the condit ions of temperature and humidity adjacent to a hea t-dissipating specimencan be different from the specified test values , the measurement of these parameters isprescribed in the manner used for free air conditions (see 4.4 and 4.6,2 of IEC 60068-1)

IS 9000 (Part 4) : 2008iec 60068-2-78 : 2001

4 Test chamber

The chamber and measuring system sha ll be such that:

a) sensmg devices can be located In the working space to monitor the temperature andhumidity For the testing of heat dissipating specimens, the devices are located at positionsas detined In IEC 60068-1,

b) the temperature and relative hum idity In the working space can be mainta ined at the valuesand within the to lerances prescr ibed, taking Into account the effect of the spe cimen undertest on chamber conditions. The temperature tolerances given m clause 5 are intended totake account of absolute errors In measurements and slow changes of te mpera ture

For heat-dissipating specimens , the temperature and relat ive hum idity nea r the spe cimenare Influenced by the effect of heat-diss ipation of the specimen itself and can be differentfrom the values measured in the posit ions defined in IEC 60068-1 ;

c) condensed water is continuously drained from the chamber and not re-used until re­purified,

d) no condensed water from the walls and roof of the test chamber can fall on the specimens ;

e) water utilized for the maintenance of chamber humidity shall have a resistivity of not lessthan 0,05 MUcm ,

f) the specimen under test shall not be subjected to rad iant heat from the chamberconditioning devices ,

g) In injection-type chambers , mo isture shall be injected remotely from the specimen andwithout impinging directly on it

4.1 Testing of heat-dissipating specimens

The volume of the test chamber shall be at least five times the total volume of the specimenunder test.

The distance between the specimen and the chamber walls shall be In accordance withappendix A of IEC 60068-2-2 The air speed within the chamber shall be commensurate withachieving the desired conditions.

4.2 Mounting of the specimens

The relevant specification shall prescribe specific mounting structures, which shall replicate orsimulate the thermal characteristics applicable in real life conditions . If these conditions are notdefined, the mounting device shall have the minimum influence on the heat and humidityexchanges between specimen and surrounding conditions.

2

IS 9000 (Part 4) : 2008lEe 60068-2-78 : 2001

5 Severity

The test severity IS def ined by a combination of temperatur e, relat ive humidity and tota l testduration

Unless otherwise spe cified In the rel evant s pec .ncanon tem perature and relat ive hum id ityseve rit ies may be se le cted from the fo llowing

(30 %21 ·C (93 %3) % RH

i 30 %2 1 ·C (85 %31 % RH :

i 40 %2 ' · C (93 %3) % RH ,

(40 %2) ·C (85 %3) % RH

Preferred test durations are 12 h. 16 h. 24 h. and 2, 4. 10 2 1 or 56 days

The total tempe rat ure tolerance of : 2 K IS Intende d to ta ke ac coun t of absolute errors In theme asurement, slow changes of temperature. and te mperatu re van anons of the working spaceHowever , In order to mai ntain the relative humidity with in the requir ed to le rances It IS

nec essary to keep the temperature difference between any two POints In the working space atany momen t with in narrower limi ts The requrred hu midity cond itions Will not be achieved Ifsuch temperature differences excee d 1 K It may also be necessar y to keep short termfluctuations within ! O,5 K to maint ai n the requu ed humidity

6 Initial measurements

The spe cimen sh all be Vis ua lly Ins pec ted and electric ally and mech anicall y checked. asrequired by the relevant specmca tron

7 Conditioning

The condit ioni ng sha ll be such that

a) Un less otherwise specified. the specimen shall be Introduced into the ch amber , both ofwh ich shall be at standard ambient condit ions of the laboratory . The specimen shall beIn troduced in the unpack ed, SWitched-off , ready-for-use state

In certain cases the relevant specrfication may allow the introducti on of the spe ci me n In thechamber when th is IS already at the conditions prescr ibed fo r the test , however,condensation on the specimen s lall always be avoided This can be obtained for smallspecimens by pre -heating the m to the chamber temperature

b) Adj ust the tem perature In the chamber to the prescribed seventy , and allow the spe cimento reach temperatu re stability

Temperature stability is defined In 48 of lEe 60068-1 The rate of change of temperatureshall not exceed 1 K/m in , averaged ove r a period of not mo re than 5 min Dunng tmsperiod co ndensation on the specimen shall not occ ur

3

IS 9000 (Part 4) : 2008rsc 60068-2-78 : 2001

c; Co ndensatio n can be avoid ed du ring this per io d by not Incr eas ing the absolute humi dity .

d) Adjust the hu mid ity to the prescri bed seve rity with in a tim e of not more th an 2 h.

e) Expose the speci me n to the test condit ions and duration as specified In the relevantspecif ica tion . The durat ion is measured from the time the specified con ditions areachieved

f ) The rele vant sp ecif icati on shal l define the operating condit ions and the period (or pe riods)In which they sha ll be carried ou t

g) At the end the rec overy pro cedure shall be followed .

8 Intermediate measurements

The relevant spe cif ica tio n may call for measurements during, or at the end of , conditioningwhile the specimen IS still in the chamber . If such measurements are requ ired , the rel evantspecif ication shall define the measu rements and the per iod (or periods ) at wh ich they shall beearned out For these measurements the specimen shall not be removed from the cham ber.

9 Recovery

The relevant specificatton sha ll prescribe whether recovery sha ll be made at standardatmospheric conditions for testing (see 5.3 of lEe 60068-1 ), or at controlled recoverycondit ions (see 5 41 of IEC 60068-1) If controlled recovery conditions are requ ired, thespecimen may be transferred to a second cham ber for this recovery period or may remain inthe test chamber

If the second chamber me thod is used, the changeover time shall be as short as possible .

Relative hum id ity shall be adjusted to a value of 73 % to 77 % RH in not more than 0,5 h, afterwhich the temperature shall be adjusted to laboratory temperature w ith in ±1 K in not morethan 0,5 h

The recovery time If specified in the relevant specification is counted from the moment whenthe prescribed recovery condit ions have been obtained.

10 Final measurements

The specimen shall be visually inspected and electrically and mechanically checked, asrequ ired by the relevant specification

4

IS 9000 (Part 4) : 2008lEe 60068-2-78 : 2001

11 Information to be given in the relevant specification

When thiS test is inc luded in the relevant spec if ication . the fo llowing detai ls sha ll be given asfar as they are appl icable.

Information to be given .

a) Specif ic mounting structures, if required

b) Test severities and tolerances

- temperature- relative hum idity- duration

c) Initial measurements

d) Conditioning

e) Intermediate measurements

f) Recovery conditions

g) Final measurements

MGIPF-OI6 D<ptt. of BIS/2005--4.9 .2llOI-JOO -5

Clause or subclause

42

5

6

7

8

9

10

Bureau o~ Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in anyform without the prior permission in writing of BIS. This does not preclude the free use, in course ofimplementing the standard, of necessary details, such as symbols and sizes, type or gradedesignations. Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards arealso reviewed periodically; a standard along with amendments is reaffirmed when such reviewindicates that no changes are needed; if the review indicates that changes are needed, it is taken upfor revision. Users of Indian Standards should ascertain that they are in possession of the latestamendments or edition by referring to the latest issue of 'BIS Catalogue' and 'Standards: MonthlyAdditions'.

This Indian Standard has been developed from Doc: No. L1TD 01 (3062).

Amendments Issued Since Publication

Amendment No. Date of Issue

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