Blog

What is Explosion Proof (Ex-Proof)?
Jan 11, 2017

What Is Explosion Proof?

The concept of explosion proof does not mean a product can withstand any external explosion. For a product, such as explosion proof junction boxes to be classified as explosion proof it would have to be able to contain any explosion originating within the housing due to any sparks from within and prevent igniting vapours, gases, dust or fibres in the air surrounding it.

For safety reasons, when equipment is based in hazardous areas, it is important to use high quality and certified explosion proof equipment as this would greatly reduce the risk of explosions and fire to personnel and industrial property.

There are two directives when dealing with ex-proof equipment .

  • ATEX
  • IECEX

Further explanation and details for these certificates can be found from another blog entry titled “What are ATEX and ICEX Certification?

There are altogether six types of area classification guide to classify explosion-proof environment/equipment:

  1. Type of protection

 

 

New Number (IEC)

General rules

 

EN-60079-0

Oil immersed

Ex “o”

EN-60079-6

Pressurization

Ex “p”

EN-60079-2

Power filling

Ex “q”

EN-60079-5

Flameproof enclosure

Ex “d”

EN-60079-1

Increased safety

Ex “e”

EN-60079-7

Intrinsic safety

Ex “i”

EN-60079-11

Non sparking

Ex “n”

EN-60079-15

Encapsulation

Ex “m”

EN-60079-18

IEC stands for International Electrotechnical Commission, a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic, and related technologies – collectively known as "electrotechnology".

  1. Equipment groups

Place of use

Group

Areas

Representative gas

Mines susceptible to firedamp

I

Gaseous Mines

Methane

Surface industries 

II A

Surface

Propane

II B

Ethylene

II B + H2

Ehtylene, Hydrogen

II C

Hydrogen, Acetylene

  1. Equipment protection level (gas/dust)

Gas Atmosphere

Zone 0

An area in which the mixture of explosive gas is constantly present (ex. the inside of a fuel tank).

Zone 1

An area in which a mixture of explosive gas may be present during the normal operation of the plant.

Zone 2

An area in which the mixture of explosive gas is not normally present, but is only present for brief periods of time.

Dust Atmosphere

Zone 20

An area in which the mixture of explosive powder is constantly present (ex. the inside of fuel tank).

Zone 21

An area in which a mixture of explosive powder may be present during the normal operation of the plant.

Zone 22

An area in which the mixture of explosive powder is not normally present but is only present for brief periods of time.

  1. Temperature class

Temperature class

T1

T2

T3

T4

T5

T6

Maximum Surface

450oC

300oC

200oC

135oC

100oC

85oC

 

  1. Ingress protection (IP)

What does “IP Rating” stand for and what does it mean?

IP Ratings is a short form for Ingress Protection (IP) mark, IEC standard 60529. This system was started by the International Electrotechnical Commission or short form IEC.

IP Ratings are normally comprised of two digits that is commonly used for electrical items such as current day mobile phones or mechanical enclosures such as explosion proof enclosures. This rating would be able to tell people immediately the level of protection that the product has based on the table further below.

First figure indicates protection against dangerous access and solid foreign objects

Index

IP

Index

Second figure indicates protection against water penetration

Non-protected

0

 

0

Non-protected

Protected against solid objects 50 mm Ø or more

1

 

1

Protected against vertically falling water drops

Protected against solid objects 12.5 mm Ø or more

2

 

2

Protected against vertically falling drops water enclosure tilted up to 15º

Protected against solid objects 2.5 mm Ø or more

3

 

3

Protected against spraying water up to 60º from vertical

Protected against solid objects 1 mm Ø or more

4

5   4

4

Protected against splashing water from any direction

Dust-protected

5

5

Protected against jets of water from any direction

Dust-tight

6

 

6

Protected against powerful jets of water from any direction

7

Protected against immersion

8

Protected against continuous immersion

The minimum requirement for Explosion-Proof protection is IP54.

  1. Ex “d” and Ex “e”

Ex e standard (IEC60079-7)

This standard has an emphasis on increased safety which in turn for products to be able to be granted this standard, they must be able to withstand excessive temperatures as well as sparks inside and outside of the enclosure.

Common uses of this standard are for products such as terminal boxes, control boxes and light fittings.

Ex d standard (IEC60079-1)

This standard focuses on resistance to flame within the enclosure. The enclosure needs to be able to safely contain any explosion and the accompanying pressure that develops and prevent any fire or sparks from escaping the enclosure and into the surrounding explosive environments.

Equipment that has this standard can be products such as control equipment or transformers.

Supermec mostly caters to Ex “d” and Ex “e” types of protection. The table below shows the advantages and disadvantages of the two:

 

Advantages

Disadvantages

Ex “d”

1. capable of withholding a possible internal explosion and prevent its transmission to the atmosphere outside the housing

2.  higher class of protection

3. easily available and cheaper components

1. maintenance more complicated ( e.g. difficult to change fluorescent tubes)

2. piped plant (where requested) complicated

Ex “e”

1. easy installation

2. pleasant appearance

3. safety cut-off switch

1. high cost of spare parts (components must be Ex type)

2. frequent and costly maintenance (e.g. seal)

You may read more about Ex “d” vs Ex “e” in another blog post here.

Summary

As the leader in the hazardous environment providing safety solutions since 1977, Supermec offers a wide range of Ex e and Ex d explosion proof products, such as explosive proof lightning and explosive proof junction boxes to cater to your hazardous area needs.

All of our products are customised to meet the strictest guidelines and standards in the industry.

Contact our friendly sales team at sales@supermec.com or you can drop us a call at +65 68619522 to find out more about our explosion proof solutions. Alternatively, you can visit our ecommerce platform and register for a free account here where you can browse through and order online the complete range of explosion proof products for various hazardous areas at your own time.


Back