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Instrumentation explosion-proof classification

Public number: Fluid Machinery Online Source: Time: 2020-02-21 01:41:14

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I. Dangerous Division of Dangerous Places:

Explosive substance

Area definition

Chinese standard

North American Standard

gas

CLASS Ⅰ

Places where explosive gas mixtures are continuously or prolonged under normal circumstances

Zone 0

Div.1

Places where explosive gas mixtures can occur under normal circumstances

zone 1

Places where explosive gas mixtures are unlikely to occur under normal circumstances, but only occasionally or for a short time under abnormal conditions

Zone 2

Div. 2

dust

CLASS Ⅱ

fiber

CLASS Ⅲ

Under normal circumstances, places where explosive dust or combustible fiber and air may be continuous, frequently appear for a short time or exist for a long time

District 10

Div.1

Under normal circumstances, explosive dust or a mixture of combustible fibers and air can not appear, only in unusual circumstances, occasionally or for a short time

District 11

Div. 2

 

Applicability of explosion-proof methods to hazardous locations:

Serial number

Explosion-proof type

Code

National standard

Explosion protection measures

Application area

1

Flameproof

d

GB3836.2

Isolate existing ignition sources

Zone1, Zone2

2

Increased safety

e

GB3836.3

Try to prevent ignition sources

Zone1, Zone2

3

Intrinsic safety

ia

GB3836.4

Limit the energy of the ignition source

Zone0, Zone2

Intrinsic safety

ib

GB3836.4

Limit the energy of the ignition source

Zone1, Zone2

4

Positive pressure type

p

GB3836.5

Separation of hazardous materials from ignition sources

Zone1, Zone2

5

Oil-filled

o

GB3836.6

Separation of hazardous materials from ignition sources

Zone1, Zone2

6

Sand-filled

q

GB3836.7

Separation of hazardous materials from ignition sources

Zone1, Zone2

7

Non-sparking

n

GB3836.8

Try to prevent ignition sources

Zone2

8

Encapsulated

m

GB3836.9

Try to prevent ignition sources

Zone1, Zone2

9

Airtight

h

GB3836.10

Try to prevent ignition sources

Zone1, Zone2

 

Applicability of explosion protection to hazardous locations:

Classification of explosive dangerous gases

According to the minimum spark energy that can be detonated, explosive gases are classified into four dangerous levels in China, Europe and most countries and regions in the world, as shown in the following table:

Working condition category

Gas classification

Representative gas


513 hit an idiom

Minimum detonation spark energy

Under the mine

I

Methane

0.280mJ

Factory outside the mine

ⅡA

Propane

0.180mJ

ⅡB

Ethylene

0.060mJ

ⅡC

hydrogen

0.019mJ

Fourth, the division of gas temperature groups:

Temperature group

Safe object surface temperature

Common explosive gases

T1

≤ 450 ℃

46 kinds of hydrogen, acrylonitrile, etc.

T2

≤ 300 ℃

47 types of acetylene, ethylene, etc.

T3

≤ 200 ℃

36 types including gasoline, butenal

T4

≤ 135 ℃

6 types including acetaldehyde and tetrafluoroethylene

T5

≤ 100 ℃

Carbon disulfide

T6

≤ 85 ℃

Ethyl nitrate and ethyl nitrite

V. Explosion-proof mark of instrument

Meaning of Ex (ia) ⅡC T6:

Logo content

symbol

meaning

Explosion protection statement

Ex

Meet certain explosion-proof standards, such as China's national standards

Explosion-proof mode

ia

Use ia class intrinsically safe explosion-proof method, can be installed in zone 0

Gas category

ⅡC

Permitted to involve IIC explosive gas

Temperature group

T6

Meter surface temperature does not exceed 85 ℃

 

Meaning of Ex (ia) ⅡC

Logo content

symbol

meaning

Explosion protection statement

Ex

Complies with European explosion-proof standards

Explosion-proof mode

ia

Use ia class intrinsically safe explosion-proof method, can be installed in zone 0

Gas category

ⅡC

Permitted to involve IIC explosive gas

Note: There is no temperature group item in this mark, indicating that the instrument is not in direct contact with explosive gas.

Six, explosion-proof term:

Seven, explosion-proof mark format description:

Scientifically classify the explosive hazardous medium of a factory or mining area according to its ignition energy, minimum ignition temperature, and the time period of the presence of explosive hazardous gases on site to determine the explosion-proof mark and explosion-proof form of the on-site explosion-proof equipment.

Explosion-proof grade description:

ia Level:

Electrical equipment that cannot ignite explosive gas mixtures during normal operation, one fault and two faults.

In normal operation, the safety factor is 2.0;

When a fault occurs, the safety factor is 1.5;

In the case of two faults, the safety factor is 1.0.

Note: Contacts with sparks must be provided with flameproof enclosure, airtight enclosure or double the safety factor.

ib level:

Electrical equipment that cannot ignite explosive gas mixtures during normal operation and a fault.

In normal operation, the safety factor is 2.0; in the case of a fault, the safety factor is 1.5.

During normal operation, the sparked contacts must be protected by flameproof enclosures or airtight enclosures, and there are measures for self-display of failures. In the case of a failure, the safety factor is 1.0.

END

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