General Technical Info

8/10/2019 General Technical Info

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Pioneers

The increa sing dema nds o f indus try for depend a ble explos ionproof lighting, motivated Ba liga to pioneer the design

and manufacture of a quality line way back in 1962, when the first Indian Standards were just being formulated.

Quality and Dependabilityhave bee n synonymous w ith Ba liga produc ts, ever since.

Ex-ENGINEERING

In order to maintain their poisition as market leaders,

Baliga have a continuous program of value engineering

and product d evelopment. This ha s ens ured a

continuous flow of new ideas and new products. A

programe aided by the latest CAD, and photometric

equipment.

Quality

Customers rely on Baliga as a very dependable source

and for good reason since each product goes through

regorous c hecks a t every stage of manufacture with the

results docmented for traceability. And ofcourse Baliga

products have the stamp of approval of various

ce rtifying a uthorities .


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Self Sufficient Factory

Quality can only be achieved with matching production

facilities. Baliga products are manufactured in a completely self

sufficient factory in Madras with over 35,000 sq.f t . of

manufacturing space. A factory that houses a wide range of

machine tools for machining, sheet metal fabrication and

moulding of plastic components. In line with the polcy of

continuous upgradation of technology, a sophisticated epoxy

pow der co ating eq uipment wa s installed in 1982. And a lmost all

operations are computerised, right from order processing,

co sting, produc tion planning and des igning. This g ives the

customer, high-quality products delivered on time.

Customer Service

Baliga is proud to offer their extensive experience in lighting

hazarous areas, as another area of total commitment to the

customer. A nationwide network of experienced agents and

representatives are available to discuss any lighting or

Exproblem and arrive at the ideal cost effective solution. Baliga

The na me sp ells q uality w ithout a single comp romise.


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Introduction

It is an inevitable fact that the manufacture, processing and

storage of petroleum products and chemicals in the liquid or

vapour form, leads to the formation of highly explosive

atmospheres due to the leakage of ga ses a nd vapours. When

these combine with the oxygen in the atmosphere, potentially

explosive mixtures comes into accidental contact with an

electrical spark or hot surface, with the resulting explosion

ca using extensive da mag e to life and property. Explosion

protec tion is therefore the sc ience of d esigning and developing

electrica l produc ts for sa fe use in these highly explosive a rea s.

Combustion PrinciplesThree ba sic co nditions mus t be sa tisfied for a fire or explosion

to occur :

1. A flammab le, liquid, vapour or combustible dust must be

present in s ufficient q uantity.

2. The flamma ble liq uid, vapo ur or dust must be mixed w ith

air or oxygen in the proportions required to produce an

explosive mixture.

3. A source of energy must be a pplied to the explosive

mixture.

The a pplica tion of the ab ove principles involves a clea r

understanding of the characteristics of the flammable gas or

liquid and the source of ignition.

Flammable gas/vapour risk

To d esign or s elect an e q uipment for haza rdous areas , it is

essential to understand the various parameters which affect

the explosive cha rac teristics o f the fla mma ble ga s/air mixture.

The pow er of a ny explosion de pends upon the inherent

properties of the gas and its concentration in the atmosphere.

Not all concentrations of the flammable gas in air will burn or

explode.

The Low er Explosive Limit (LEL) is the low es t co nc entra tion of

the gas in air which can cause an explosion.

The U ppe r Explos ive Limit (UEL) is the m a ximum co nc entra tion

of the gas in air beyond which no explosion can take place.

Upper and Lower Explosive Limits in Gases

Flam ma ble liquids g enera lly have a low Flas h Po int. This is the

low est temperature a t w hich vapour is given off at a sufficient

rate to fo rm a n explosive mixture with air. Therefo re liq uids

with flash points below ambient temperature will automatically

release vapour in sufficient quantities to provide an explosive

mixture.

Vapo ur Density is a mea sure of the de nsity of the ga s relative

to air. A know ledg e of this pa rameter is important a s g as es

lighter than a ir tend to rise up from the po int of es ca pe a nd ma y

therefore disperse e as ily. Heavier than air ga ses tend to s ink

and accumulate over a period of time to form concentrations

between the LEL and UEL ready to explode as soon as a

source of ignition is introduced.

When a n explosive mixture of s ufficient co nce ntration has b een

developed, it ca n be ignited by a spa rk o s ufficient energy or if

it is exposed to a surface at a sufficiently high temperature.

The lowe st te mpera ture which w ill ca use the mixture to

explode is ca lled the Ignition Temperature.

Sources of Ignition

A source of energy is all that is required to touch off an

explosion where flammable gases or combustible dusts are

mixed in the proper proportion with air.

For ignition of gas mixture to take place, it is necessary that

atleast a small portion of the mixture be raised to the ignitiontempe rature. By the b urning of this portion, sufficient hea t will

be e volved to ca use the ignition of the who le volume. It follow s

from this that any ignition source has two essential

characteristics.

They a re :

Tempera ture : This mus t be equa l to or h igher than the

ignition Temp era ture.

Energ y : The so urc e mus t s upply suffic ient ene rg y a t

a high enough rate, to raise enough gas

mixture to the ignition point to start a self

sustaining explosion.

The different so urce s o f energy c an b e effec tively grouped into3 categories.

a) Flames

b) S pa rks - electric or percus sive

c) Hot surfac es.

Flames

These usually have a tempera ture b etw een 1000C and

2000C. They are also ca pab le of supplying energy at a high

rate a nd c an therefore b e effective sources o f ignition.

Sparks

These have very high temperatures betw een 1000C and

3000C and are capable of supplying large amounts of energy

over short periods of time.

One prime so urce o f spa rks is elec tricity. Equipment suc h as

switches, motor starters and push button stations produce

arcs and spa rks d uring normal operation.

Area Most Prone

LEL to ignition UEL

Wea k Ignition S trong

Mixture Area Mixture

6% 14% 20% 40% 100%

Hydrogen (H2) 4% 14% 34% 76%

Acetylene(C2H2) 1% 6% 12% 80%

Metha ne(CH4) 5% 8% 9% 15%


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Another source of sparks is static electricity. Present wherever

there is a flow of liq uids &ga ses through hos es and pipelines,

the static charge accumulated can over a period of time

generate sparks of sufficient energy to initiate an explosion.

Non-electrical hazards such as sparking of metal can also

ea sily ca use a n ignition. A ham mer, file or other tools w hen

dropped o n masonry or on a ferrous surface ca n cause a spark

with sufficient energy to trigger an explosion.

It is therefore necessary that in order to ignite a given

flamma ble atmos phere, sufficient energy has to b e s upplied to

raise the temperature of gases locally to their ignition

tempe rature. The minimum energy req uired to do this is

dependant upon the gas present and varies widely from one

ga s to another. Bec ause of this wide variation, it has b een

found c onvenient to determine the Minimum Ignition Energy

for four gas groups classified I to IIC in the direction of their

increa sing s ens itivity to spa rk ignition.

They a re :

G a s G roup No. Minimum ignition Energy

Metha ne I 280

P ropa ne IIA 260

Ethylene IIB 85

Hydrogen IIC 19

Hot Surfaces

The third s ource o f ignition is the s urface tempe rature

developed by the product during normal operation like in

lighting fixtures or mo tors.

Here the surface temperature may exceed the safe limits of

many flamma ble a tmospheres, thereby initiating a n explosion.

Other components of the electrical system can also become

potential sources of ignition in the event of insulation failures

for example : in trans formers, impeda nce coils, s olenoids and

in the ba sic w iring s ystem.

Electrical safety therefore, is of crucial importance and the

electrical installation must be designed to prevent the

accidental ignition of flammable liquids, vapours and dusts

released to the atmosphere.

Classification of Hazardous materials

The NEC has c lass ified a ll ma terials c a pa ble of forming a n

explosive atmos phere into three major clas ses :-

C la ss I : A C la s s I a tmo sp he ric h a za rd is a n a re a

cons isting of gas es a nd liq uids w hich have be en

further divided into 4 groups.

C la s s II : A C la s s II ha z a rd c o vers 3 d iffe rent g ro up s o f

comb ustible dus ts ba sed upon their resistivity

C la s s III : A C la s s III h a z a rd c o v ers lo c a t io n s where

combustible fibres or flyings are present.

Zone Classification

All haza rdous areas ca n be c las sified into 3 zones a cc ording to

the probability of there being an explosive gas air mixture

prese nt .

Zone O Areas where an explosive gas atmosphere is

continuously present.

Typica l eg .: inside o f conta iners or reac tors.

Zone 1 Areas where an explosive gas atmosphere

is likely to occur under normal operation.

Typica l eg .: area s s urround ing Zone 0, a reas

surrounding drains, discha rge eq uipment.

Zone 2 Areas where an explosive atmosphere is not

likely to occur in normal operation and if it doesit is only for short periods.

Typica l eg.: a rea s surrounding flang ed ga skets,

areas surrounding Zone 0 or Zone 1.

Gas Grouping

All gases and vapours can be classfied into 4 major gas

groups . The cla ss ifica tion criteria is ba se d upon lab orato ry

tests to determine the Maximum Experimental Safe Gap

(MESG) and the Minimum Ignition Current (MIC). Gas group

class ifica tion for typica l gas es will be :

IS2206

EN 50018 US A

Representa tive G a s B S 5501 P t 5 UL 698

IEC 79-1

G ROUP G ROUP

Metha ne (mining Use) I D

P ropa ne IIA D

Ethylene IIB C

Hydrogen IIC B

Ca rbon Disulphide* IIC

Acetylene* IIC A

Gases belonging to the IIC group are the most dangerous with

the se verity de crea sing d ow n the sc a le to the IIA group. The

performanc e a nd te sting req uirements of electrica l equipment

is consequently more stringent for applications in areas

conta ining IIC g as es that in areas cons isting IIA ga ses .

*IS 2206 has not yet class ified these ga ses .

Conditions for explosion

%

Concentra tion EnergyMechanical

Heat Electrica l

UPPER

EXPLOS IVE

LEVEL

LOWER

EXPLOS IVE


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Classification of flammable liquids

All flammable liquids vary in volatality and have a flash point

below 93% and a vapour pressure not excee ding 2.81 kg/m2.

These liq uids ca n be divided into 3 class es.

C lass A : Flammable liqu ids hav ing a f la sh po in t below

23C. Thes e liq uids produc e large volumes o f

vapour when relea sed in appreciable q uantities to

the open.

C lass B : Flammable liqu ids having a fla sh poin t between

23 and 65C. Thes e liq uids are hea vier and les s

volatile and have a flash point slightly below

normal ambient temperature. At elevatedtemperatures, Class B liquids approach the

characteristics of Class A liquids in vapour

release.

C lass C : Flammable liqu ids having a f la sh po in t between

65and 93C. These liq uids have a low deg ree o f

haza rd b eca use the rate of relea se is nil at normal

amb ient temperature. These include a broad

range from cleaning solvents to heavy fuel oils in

commercial grades.

Temperature Class

It is an essential requirement that for electrical equipment to

wo rk sa fely in an explosive a tmosphere, the ma ximum surfac e

temperature of the exposed surface of the equipment ust

always be lower than the ignition temperature of the gas

mixture.

In order to properly select electrical equipment with regard to

the ignition temperature, all ga ses are c las sified ac co rding to a

temperature classification scale shown below:

EN 50014

Ma ximum B S 5501 P t 1

S urfa ce IS 8239 US A

Tempera ture IEC 79-1 UL 698

C

450 T1 T1300 T2

280 T2A

260 T2B

230 T2C

215 T2D

200 T3 T3

180 T3A

165 T3B

160 T3C

135 T4 T4

120 T4A

100 T5 T585 T6 T6

Any electrical equipment to be used in an hazardous area is

also tested and rated for its maximum surface temperature.

It now bec omes relatively s imple to ensure that the temperatre

rating o f the eq uipment is alwa ys c ompa tible with temperature

classification of the gas.

For example electrical eq uipment w ith a T5 ra ting c a n be us ed

in all areas where g as es have a temperature rating from T1 to

T5 but not T6 ca tion.

IS 2206 currently requires temperature classification of Ex d

luminaires as X, Y or Z being the temperature rise of 125C,

75C and 50C respectively at an ambinet of 30C. This

sta nda rd is to b e revised shortly.

Types of Protection

The b as ic principles of providing explosion protec tion requires

the use o f a number of techniques to prevent the simultaneo us

availability of a gas air mixture of sufficient concentration and

volume and an ignition s ource w ith sufficient ene rgy. Where this

is unavoidab le, then spec ial meas ures a re taken to conta in any

explosion.

Worldw ide , se ven different type s o f protection a re currently

reco gnised as effective tec hniq ues to prvent explosions. These

types of protection are listed below.

1. Ex i : Intrinsic S afe ty

2. Ex d : Flame proof3. Ex e : Increase d S afety

4. Ex p : P ress urise d

5. Ex o : Oil Immersion

6. Ex q : P ow de r filling

7. Ex n : Non spa rking (ba sica lly in UK and India)

A new standard for providing protection using moulding

techniques Ex m is under preparation.

Each type of protection however, can be used only in specific

Zones. In Zone 0 for example, appa ratus with Ex is c ateg ory of

protection can only be used. Ex n category of apparatus cn be

used only in Zone 2 areas .

An apparatus certified for use in Zone 0 can also be used inZones 1 and 2. similarly those certified for use in Zone 1 areas

can be used in Zone 2 areas, but not in Zone 0 areas.

Zone Type of Protection

Zone 0 Ex ia

Zone 1 Ex ib

Ex d

Ex e*

Ex p

Zone 2 Ex n

Ex o

Ex q

* As per IS 5572, Ex e equipment may be used in zone 2 areas only.

As revision of this standard is under consideration.


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TE C H NIC AL D ATA

Type of protection Basic principle Schematic Applicationsto IEC or EuropeanStandard

flameproof A type of protection in which the parts, which Sw itchgea r, control andenclosure Ex d can ignite an explosive atmos phere are indicating equipment,

pla ced in a n enc losure, w hic h ca n w iths ta nd contro l boa rds , motors ,the press ure developed during a n interna l tra ns formers , light fittingsexplos ion o f a n explos ion mixture a nd w hich a nd o ther s pa rk-produc ingprevents the transmission of the explosion parts.to the explosive a tmospheres surroundingthe enclosure.

in cre a se d s a fe ty A t yp e o f p ro te ct io n in w hic h m ea s ure s a re Te rm in a l a n d c o nn ec tio n

Ex e applied so as to prevent with a higher boxes, control boxesdegree o f s a fety the pos s ibility of exces s ive hous ing Ex-modules (of atempera tures a nd of the oc cura nc e different type of protec tion)of a rcs or spa rks in the interior a nd sq uirrel ca ge motors ,on the externa l pa rts o f elec trica l lig ht fittings .apparatus, which does not producethem in normal service.

pressurized appara tus A type o f pro tec tion in which the entry o f a as above , but especia l ly forEx p surrounding atmos phere into the enclosure large equipment and

of the electrical appa ratus is prevented by complete rooms.maintaining inside the s aid enclosure aprotective gas (air, inert or other suitable gas)at a higher pressure than tha t of thesurrounding atmo sphe re. The overpress ureis maintained either with or withoutcontinuous flow of the protective ga s.

intrinsic safety Ex i A type of protec tion in w hich the elec tric a l Mea s urement a nd contro lappa ratus conta ins intrinsically safe circuits, equipment.which are inca pable of ca using an explosionin the surrounding atmospheres. A circuit orpart of a circuit is intrinsically safe, when nospark or any thermal effect in this circuit,produced in the test c onditions presc ribedin the standard (which include normaloperation and specific fault conditions) iscapa ble of ca using ignition.

oil immersion Ex O A type of protec tion in w hich the elec tric a l Tra ns formers (only us ed ra rely now )appa ratus are immersed in oil in such a wa ythat an explosive atmosphere, which may be

abo ve the oil or outside the enclosurecannot be ignited.

power filling Ex q A type of protec tion in w hich the enc losure Tra ns formers , ca pa c itors , hea terof elec trica l a ppa ra tus is filled w ith a ma teria l s trip connection boxes elec tronicin a finely g ra nula ted s ta te s o tha t, in the a s semblies .intended c onditions o f service, a ny arcoccuring within the enclosure of an electricalapparatus will not ignite the surroundingatmos phere. No ignition s hall be ca usedeither by flame or b y exces sive temperatureof the surfaces of the enclosure.

encapsulation Ex m A type of protec tion in w hich the pa rts w hich only sma ll c a pa c ity sw itchg era ,(in prepa ra tion) ca n ig nite a n explos ive a tmosphere a re contro l gea r, indica ting eq uipment,

enc losed in a res in suffic iently res is ta nt to sensors .environmental influences in such a wa y thatthis explosive atmosphere cannot b eignited by either sparking or heating, whichmay o ccur within the enca psulation.

Types of Protection


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TE C H NIC AL D ATA

IP Degree of Protection

All electrica l apparatus, d epending on the ultimate applica tion, need to be protected to varying d eg rees from the effects of

conta ct w ith foreign b odies, d ust a nd w ater. This d egree of protection is s hown in the tab le b elow.

1st figure : 2nd figure : 3rd figure :

protection against solid protection against liquids mechanical

IP tests IP tests IP tests

0 No protection 0 No protec tion 0 No protection

P rotec ted a g a ins t P rotec ted a g a ins t Impa ct energ y

solid bodies la rg er vertica lly - fa lling 0.225 joule1 than 50 mm 1 drops of water 1

(eg . : a cc identa l (c ondens a tion)contac t with thehand)

P rotec ted a g a ins t P rotec ted a g a ins t Impa ct energ ysolid bodies la rg er drops of wa ter 0.375 joule

2 than 12 mm 2 falling at up to 2(eg . : fing er of the 15 from theha nd) vertica l

P rotec ted a g a ins t P rotec ted a g a ins t Impa ct energ ysolid bodies la rg er drops of ra in 0.500 joule

3 than 2.5 mm 3 wa ter at up to 60 3(eg . : tools w ires ) from the vertica l

P rotec ted a g a ins t P rotec ted a g a ins t Impa ct energ ysolid bodies la rg er drops of ra in 2.00 joules

4 than 1 mm 4 water from all 5(fine tools a nd direc tionssma ll wires)

P rotec ted a g a ins t P rotec ted a g a ins t Impa ct energ y5 dust (no ha rmful 5 jets of water from 7 6.00 joules

depos it a ll direc tions

C ompletely P rotec ted a g a ins t Impa ct energ y6 protected against 6 jets o f wa ter of 9 20.00 joules

dus t s imila r force toheavy seas

The 3rd figure is specific to the FrenchProtected against standard U.T.E. 20 010

7 the effects o fimmers io n S ta nd ard EN 500 14 defines the impa ct

tests to b e ca rried out a cco rding tomaterials used and the groups to whichthey belong.

Protected aginst

prolonged effects8 of immersion

under press ure


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TE C H NIC AL D ATA

Selection of Electrical Equipment

A number of logical steps are involved in the proper selection

of electrica l eq uipment for hazardous a reas.

Step 1 : Clearly identify the gas/vapour, its gas group and

temperature class.

S e tp 2 : D efine the a rea Zo ne 0, 1, or 2

Step 3 : Selec t the type o f p ro tec t ion appropria te to the

Zone

S t ep 4 : Fo r t he g iv en t y pe o f p ro t ec tio n s e lec t t he

eq uipment keeping in mind the g as group and the

temperature rating

Step 5 : Depending on whether the equ ipment is to be

installed indoor or outdoor, ensure the correct IP

protection for the equipment

Guide to certification code

Apparatus marking requirements normally include a

certification code which includes the following elements.

a . Symbol f r the type o f p ro tec t ion

b . The a pp a ra tus g ro up

c . The tempera ture c l a ss if ica t ion

EXAMP LE 1. Ex d II B T5

This indicat es a unit having flameproof typ e of protec tion d

suitable for apparatus gas group IIA and II B and having a

maximum surface temperature classification of 100C (T5)

EXAMP LE 2. Ex. N II T6

This indicat es a unit having non-spa rking typ e of protec tion N

suitable for apparatus gas groups IIA, IIB and IIC (absence of

letter indicates all gas groups ) having maximum surface

temperature classification of 85C (T6)

Inspection, maintenance and testingThe sa fe and sa tisfac tory operation of electrica l apparatus is

dependant on a high standard of inspection, maintenance and

testing by trained and competent personnel.

General recommendations for inspection, maintenance and

testing given herein apply particularly to type of protection d

flame proof enclosures.

Initial and periodic inspections

All electrical apparatus, systems and installations should be

inspected prior to commissioning and after replacement in

ac cordance w ith the initialc olumn of the inspec tion s ched ule.

Following any repair, adjustment or modification, those parts of

the installation that have bee n disturbed should b e c hecked in

ac corda nce w ith the relevant items in the initia lcolumn of the

inspec tion s ched ule.

If, at any time, there is a cha nge in the a rea class ifica tion or in

the characteristics of the flammable material used in the area,

or if the apparatus is moved from one location to another, a

check should b e ma de to ensure that the a pparatus c oncerned

has the correct a pparatus subgroup and temperature c las s and

that it complies with the relevant area classification.

A system should be established to record the results of all

inspections and the action taken to correct defects.

Maintenance

No alteration that might invalidate the certificate or other

document relating to the safety of the apparatus should be

made to any apparatus without appropriate approval.

If replacement components such as cable glands, conduit or

cond uit ac ces sories, are a vailab le only with threa d forms w hich

differ from those provided on the a pparatus, suitab le a da ptors

having component approval should be employed.

Checks should be made for obstructions around flanges of

eq uipment. The dimensions of the ga ps at flam eproof jointsshould b e chec ked periodica lly during ma intenance to se e that

they do not exceed the maximum figure specified in IS-2148.

At such intervals as experience may prove desirable, the

flanged joints should be separated and the faces examined for

possible defects resulting from corrosion, erosion or other

ca uses. If flanges are to be sea led, then new nonsetting grease

or tape should be used on reassembly.

Equipment enclosures and fittings should be examined to see

that all stopping plugs and bolts are in position and tight.

Locking a nd se aling de vices should be c hecked to c onfirm that

they a re s ecured in the presc ribed manner.

Replacement cover securing fasteners, nuts, studs and bolts

should be types spec ified by the manufac turer for the pa rticular

apparatus.

No attempt should be made to replace or repair a glass in a

flameproof enclosure e.g. in a luminaire or other enclosures,

except by the complete assembly or part obtainable from the

manufacturer, or complying with the flameproof certificate.

Repairs and refurbishing of apparatus with type of protection

d should be performed only by the original manufacturer, his

authorised agents or a repairer who is conversant with the

construction standards for flameproof equipment and

demo nstrates the a bility to understand certifica tion restraints.


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TE C H NIC AL D ATA

Inspection Category

C heck tha t Initia l P eriodic Notes

Appa ra tus is a ppropria te to a rea c la ss ifica tion A B

S urfa c e tempera ture c la ss is correc t A B

Appa ra tus subgroup is c orrec t A A

Appa ra tus ca rries the c orrec t c ircuit identific a tion A B Appa ra tus should be pos itively

identified w ith its circuit to ens ure

that correct isolation can be

ca rried out.

Obs truc tions a re not present nea r fla nged joints A AEnc losures , g la ss es and gla ss/meta l sea ls are sa tis fa c tory A A

G a ps a re free from c orros ion, d irt a nd pa int A B

Dimens ions of g a ps a re correc t A B

There a re no una uthorized modifica tions A A

B olts , g la nds a nd s toppers a re complete a nd tight. A A

There is no undue a c cumula tion of dus t or d irt B B Acc umula tion of dus t or d irt ca n

interfere with heat dissipation and

result in surface temperatures

higher than those permitted in the

hazardous area.

All c ond uits runs and fitting s a re tig ht a nd fre e fro m c orro sio n A B

Ea rthing is s a tis fa c tory A A

Elec tric a l c onnec tions a re tight A B

Motor fa ns and couplings are not rubbing on cow ls/gua rds A A

La mp ra ting a nd type a re c orrec t A B An initia l inspection is nec essa ry

after relamping

S topper boxes a nd ca ble boxes a re c orrec tly filled A B

There is no lea ka ge of c ompound from B B

stopper or cable boxes

There is no obvious da ma ge to ca bles , A A

c a ble shea ts or c a ble g la nds P a rtic ula r a ttention should be pa id to

flexible ca bles use d w ith portable

apparatus.

Appa ra tus is a d eq ua te ly pro te cte d a g a ins t c orro sio n, A A

the w ea ther, vibration and o ther adverse fa torsG ua rds , w here used , a re present a nd c orrec tly loc a ted A B

*Category A inspections should be carried out in all cases and, where periodic, at intervals not exceeding two years. More

freq uent and /or more deta iled inspec tion w ill be nec ess ary w here there is co rrosive or other ad verse a tmosphere, a high risk

of mecha nica l da mag e or vibration, or where there are other onerous c ircumstance s. The need for more freq uent inspec tion

may also be determined by operating experience.

The need for, the method , a nd the frequenc y of c ateg ory B inspec tions is at the discretion of the engineer respo nsible. It is not

intended that periodic inspec tions s hould incur undue disturba nces of appa ratus, unless cons idered nec ess ary by the eng ineer

responsible.

The a bove cha rt is reproduced from B S 5345 P art I.

Sample Inspection Schedule


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TE C H NIC AL D ATA

Indian Standards for Explosive Atmospheres / Areas

General specifications

IS4051/1967 Cod e o f practice for installation &maintenanc e o f electrica l equipment used in mines.

IS 5571/1979 Guide for the selection of electrica l eq uipments for haza rdous areas .

IS 5572/1978 P a rt I Class ifica tion o f ha zardous areas for electrica l insta llation.

IS 7820/1975 Method of test for ignition temperatures.

IS 8239/1976 Classification of maximum surface temperatures of electrical equipment for use in

explosive atmos pheres.

IS 8240/1976 Guide for e lectrica l equipment for explosive a tmospheres.

IS 8241/1976 Method of marking for identifying electrical equipment for explosive atmospheres.

IS9570/1980 Class ifica tion o f flamma ble ga ses ac cording to their MESG /MICIS 9559/1980 Guide for selection of electrical &electronic equipment for coal mines.

IS 13408/1992 P a rt I Cod e of prac tice for the selection, insta llation and maintenance o f electrica l apparatus for

use in explosive atmospheres (other than mining applications).

IS 139417(Pt 1)/1993 Ingners P rotec tion

Specification for the types of protection

IS 13346 /1992 Ge neral req uirements for electrica l appa ratus for e xplosive a tmospheres

IS 2148 /1981 Spe cifica tion for flame proof enclosures of electrica l appa ratus.

IS 5780 /1980 Intrinsically safe electrical apparatus and circuits.

IS 6381 /1972 Spe cifica tion for c onstruction &tes ting of electrica l appa ratus w ith type of protection e .

IS 7389 /1976 Part I Spe cifica tion for pressurised enclosures of electrica l apparatus for use

in e xplosive a tmospheres.IS 7693 /1975 Spe cifica tion for oil immersed electrica l apparatus for use in explosive ga s atmos pheres.

IS 7724 /1975 Specification for sand filled protection of electrical equipment for use in

explosive atmos pheres.

IS 8289 /1976 Specification for electrical equipment with type of protection n

IS 11005 /1984 Spe cifica tion for dust tight ignition proof enclosures of electrical equipment

Product specifications

IS 2206/1984 P a rt I S pec ifica tion fo r FLP electric lighting fittings Wellglas s &Bulkhea d

IS 2206 /1976 P a rt II S pec ifica tion for FLP e lec tric lighting fittings using glass tubes

IS 2206 /1987 Part IV S pec ifica tion fo r FLP electric lighting fittings Portable flameproof hand lamps.

IS 4012 /1967 Dust p roof elec tric light fittings .

IS 4013 /1967 Dust t ight electric light fittings .IS 4821 /1968 Specification for cable glands and cable sealing boxes for use in mines.

IS 6539 /1972 Intrinsically sa fe ma gneto telephones for use in haza rdous atmos pheres

IS 6789 /1972 Bolted flameproof cable couplers &adaptors

IS 8224 /1976 S pec ifica tion fo r lighting fittings for Division 2 a reas

IS 8945 /1987 Spe cifica tion for e lectrica l meas uring instruments for explosive g as atmos pheres

IS 9099 /1979 Part I Pe rformance testing of pow ered industrial trucks wo rking in haza rdous a reas

(IC engine powered)

IS 9099 /1980 Part II Pe rformance testing of pow ered industrial trucks wo rking in haza rdous a reas

(ba ttery operate d)

IS 9628 /1980 Three phas e induction motors w ith type of protec tion n

Documents

General Technical Info