EEx & IPPrepared by

Mohamed Nasr

Mohamed Eissa

Content• Hazard Areas

Zone area classificationExplosion triangle

• European ATEX/CENELEC Code

• IP Code

Hazard AreasHazard AreasWhere fire or explosion hazards may exist due to the presence of flammable gases or vapors, flammable liquids, combustible dusts, or easily ignitable fibers.

Hazard Area Classifications- “Class, Division” in North America: hazardous locations are divided into three Classes, and two Divisions. - “Zone System” in rest of the world: hazardous locations are divided into three Zones.

Zone area classification

Frequency of Occurrence Presence in

hours/year

Hazard Zones Gas or Vapors (Dusts)

Continuous >1000h Zone 0 (20)

Primary 10h to 1000h Zone 1 (21)

Secondary 0.1h to 10h Zone 2 (22)

Explosion triangle• Three elements are required for an explosion

to occur - fuel, oxygen and a heat or ignition source must be present.

• The fuel and oxygen must be in the correct mixture. Too little fuel, or a lean mixture, or too much fuel, a rich mixture cannot ignite.

• These explosive limits are defined as the “Lower Explosive Limit” (LEL) and the “Upper Explosive Limit” (UEL).

IgnitionEnergy(J)

VolumeConcentration (%)

L.E.L.Lower Explosive Limit

U.E.L.Upper Explosive Limit

M.I.EMin. IgnitionEnergy

GAS/APPARATUS CLASSIFICATION

RepresentativeGAS

Methane (Firedamp)

PropaneEthyleneHydrogen

52

2.74

L.E.L.(%)

159.53475

U.E.L.(%)

3201806020

M.I.E.(µJ)

I (Mining)IIAIIBIIC

GASGroup

Ignition characteristics

European ATEX/CENELEC Code

ــــــ ــــــ ــــــ ــــــــــــ ــــــ Temperature

Class

Gas Group

Methods of protection

Equipmentcategory

Equipmentgroup

Explosion protected accordingto CENELEC standards

EEx

EX Code DetailsEquipment

GroupGas Group Equipment

CategoryPresence of Explosive

Atmosphere

Protection Level

IMines

and related surface

installations

Methane (I)

M1 Present Very High

M2 Likely to be present High

IISurface Industries

and other locations.

Gas Vaporsor

Dusts

propane (IIA) ethylene (IIB) hydrogen (IIC)

1 (G/D) Continuously, frequently or for long

periods.

Very High

2 (G/D) Occasionally during normal operation.

High

3 (G/D) Not expected, in case, only for short periods.

Normal

Methods of Protection

There are different methods to protect equipment against explosions. Each method of protection addresses the Fire Triangle in some manner. Either by containing an internal explosion or eliminating one or more of the components

necessary for an explosion to occur.

Type of Protection

Type of Protection (cont’d)

The lowest liquid temperature at which a liquid gives off vapors in a quantity such to be capable of forming an ignitable vapor/air mixture

The temperature of a liquid boiling at an ambient pressure of 101,3 kPa (1013 mbar).

The lowest temperature of a heated surface at which the ignition of a flammable substance in the form of a gas or vapor mixture with air will occur.The Ignition Temperature must not be confused with the maximum operating temperature of the apparatus for which it has been designed.

Flash point

Boiling point

Ignition temperature

Temperature definitions

Maximum operating temperatureNorth AmericanTemperature Code

IEC/CENELEC/NEC 505Temperature Classes

Maximum Temperature

T1 T1 450 ˚CT2 T2 300 ˚CT2A - 280 ˚CT2B - 260 ˚CT2C - 230 ˚CT2D - 215 ˚CT3 T3 200 ˚CT3A - 180 ˚CT3B - 165 ˚CT3C - 160 ˚CT4 T4 135 ˚CT4A - 120 ˚CT5 T5 100 ˚CT6 T6 85 ˚C

Temperature classes- The maximum temperature of a piece of

equipment must always be lower than the ignition temperature of the gas - air mixture or vapor - air mixture in which it is placed.

- Equipment shall be marked to show the operating temperature or temperature class.

- The temperature class (T code) is based on the next table.

IP Code

IP Code format

Solid particle protection

Liquid ingress protection

IP Code• The IP Code (International Protection) Marking, IEC standard 60529, sometimes interpreted as Ingress Protection Marking, classifies and rates the degree of

protection provided against intrusion (body parts such as hands and fingers), dust, accidental contact, and water by

mechanical casings and electrical enclosures.

IP Code format

• The IP code forming in a characteristic numerals, each digit indicates the level of protection that the enclosure provides against access to hazardous parts.

• If there is no data available to specify a protection rating with regard to one of the criteria, the digit is replaced with the letter X.

• The digit 0 is used where no protection is provided.

Code breakdown

IP indication Solid particle protection

Liquid ingress protection

Mechanical impact

resistanceOther

protections

IP Single numeral: 0–6

Single numeral: 0–8

Single numeral: 0–9 Single letter

Mandatory Mandatory Mandatory No longer used Optional

Mechanical impact resistance

• An additional number has sometimes been used to specify the resistance of equipment to mechanical impact. This has now been superseded by the separate 'IK code' specified in EN 62262.

• Older enclosure specifications will sometimes be seen with an optional third IP digit denoting impact resistance. Newer products are likely to be given an IK rating instead. However, there is not an exact correspondence of values between the old and new standards.

Mechanical impact resistance (cont’d)

Approximate IK equivalents to IP drop level

DroppedIP level

Impactenergy

Equivalent impact

IKnumber

Impact energy(joules)

Equivalent impact

0 — — 00 Unprotected No test

01 0.15 Drop of 200 g object from 7.5 cm height

1 0.225 J 150 g dropped from 15 cm 02 0.2 Drop of 200 g object

from 10 cm height

2 0.375 J 250 g dropped from 15 cm 03 0.35 Drop of 200 g object

from 17.5 cm height

3 0.5 J 250 g dropped from 20 cm 04 0.5 Drop of 200 g object

from 25 cm height

05 0.7 Drop of 200 g object from 35 cm height

Mechanical impact resistance (cont’d)

5 2 J 500 g dropped from 40 cm 06 1 Drop of 500 g object

from 20 cm height

07 2 Drop of 500 g object from 40 cm height

7 6 J 1.5 kg dropped from 40 cm 08 5 Drop of 1.7 kg object

from 29.5 cm height

09 10 Drop of 5 kg object from 20 cm height

9 20 J 5.0 kg dropped from 40 cm 10 20 Drop of 5 kg object

from 40 cm height

Additional letters

Level Protected against access to hazardous parts with

A Back of hand

B Finger

C Tool

D Wire

Letter Meaning

F Oil resistant

H High voltage device

M Device moving during water test

S Device standing still during water test

W Weather conditions

SummaryWhat Did We Cover?

• Describe the Hazard Area and it’s classification

• Describe the Ex code and Methods of Protection

• Describe the IP code and it’s format